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1
Biddulph, Thomas Benjamin. "Mechanisms of dormancy, preharvest sprouting tolerance and how they are influenced by the environment during grain filling and maturation in wheat (Triticum aestivum L.) /." Connect to this title, 2006. http://theses.library.uwa.edu.au/adt-WU2007.0168.
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Biddulph, Thomas Benjamin. "Mechanisms of dormancy, preharvest sprouting tolerance and how they are influenced by the environment during grain filling and maturation in wheat (Triticum aestivum L.)." University of Western Australia. School of Plant Biology, 2007. http://theses.library.uwa.edu.au/adt-WU2007.0168.
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[Truncated abstract] Wheat is the main crop in Australia and there are stringent quality requirements. Preharvest sprouting induced by rainfall between maturity and harvest lowers grain quality from premium to feed grades and reduces yield. Wheat production has expanded into the southern Western Australian region where preharvest sprouting occurs in ~1 in 4 seasons and development of more preharvest sprouting tolerant genotypes is required. The main mechanism for improving preharvest sprouting tolerance is grain dormancy. There is genetic variation for dormancy based in the embryo and seed coat but dormancy is complex and is influenced by environmental conditions during grain filling and maturation. Screening and selecting for preharvest sprouting tolerance is problematic and the level of tolerance needed for regions which differ in the level of dormancy they impose, requires clarification. The research presented here aims to answer the underlying question for breeders of how much dormancy is required for preharvest sprouting tolerance in contrasting target environments of the central and coastal wheat belt regions of Western Australia. In the central and coastal wheat belt regions, field trials with modified environments were used to determine the environmental influence on dormancy. Water supply (without directly wetting the grain) and air temperature were modified during grain development in a range of genotypes with different mechanisms of dormancy to determine the influence of environment on dormancy. ... Genotypes with embryo dormancy were consistently the most preharvest sprouting tolerant, even though this dormancy was influenced by the environmental conditions in the different seasons. Pyramiding the embryo component with the specific seed coat component and/or awnless head trait removed some of the environmental variation in preharvest sprouting tolerance, but this was generally considered excessive to the environmental requirements. The methods developed here, of field imposed stresses may provide a valuable tool to further understand the influence of environment on the regulation of dormancy, as different phenotypes can be made with the same genotype. Moisture stress, sudden changes in water supply or high temperatures during the late dough stages influenced dormancy phenotype and should be considered and avoided if possible when selecting locations and running trials for screening for genetic differences in preharvest sprouting tolerance. In the Western Australian context, the embryo component of dormancy appeared to be sufficient and should be adopted as the most important trait for breeding for preharvest sprouting tolerance.
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Pisipati, Sudha R. "Pre-harvest sprouting tolerance in hard white winter wheat." Thesis, Manhattan, Kan. : Kansas State University, 2008. http://hdl.handle.net/2097/1062.
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Hayta, Mehmet. "Thermal transitions in wheat gluten." Thesis, University of Reading, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.299298.
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Moss, Diane Patricia. "Gaseous ammonia exchange in wheat crops." Thesis, Imperial College London, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.271216.
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Howladar, Saad Mohammed. "Effects of salicylic acid on salinity tolerance of wheat (Triticum aestivum)." Thesis, University of Reading, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.553172.
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Four glasshouse experiments examined salinity stress and tolerance in wheat. The first experiment examined the responses of three wheat cultivars from Saudi Arabia (Local wheat, West bread and Yecora Rojo) and two UK wheat cultivars (Paragon and Belvoir) to different levels of salinity (Tap water, 25, 50, 100, 150 and 200 mM NaCI). In the second experiment, Yecora Rojo and Paragon were selected to test whether improved wheat tolerance to salinity could be obtained by applying exogenous Salicylic acid (0, 0.5, 1 and 2 mM SA) via priming seeds for 6 hours. The third experiment further tested the effect of SA on tolerance to salinity with SA applied through seed soaking for 6h and 24h. Two salinity tolerant cultivars (S24 and Sakha 93) were included for comparison. The fourth experiment compared the effect of SA applied by seed soaking (6h) or by foliar spray. In all experiments, saline conditions gave significant declines in wheat growth parameters, gas exchange, yield and yield components with increases in salinity concentration, whereas protein and chlorophyll content increased. Cultivar Paragon grew significantly better than cultivar Yecora Rojo in non-saline conditions but not under salinity stress. Treating wheat with SA produced only a minor improvement in growth parameters, yield and yield components under salinity stress. Compared to salt tolerant cultivars, Paragon showed significant response to SA in most variables. The influence of SA depended on genotype, plant stage and SA concentration more than soaking time and application method with 0.5 and 1 mM SA concentrations being the most effective. SA mitigates but does not prevent salinity impacts and has a dual function which can give positive or negative effects under salinity stress.
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Jenab, Mazda. "The influence of wheat bran and phytic acid on early biomarkers of colon carcinogenesis." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0024/NQ49962.pdf.
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Rodriguez, Miguel A. "Molecular genetic approaches to the study of aluminum tolerance and toxicity in wheat and rye /." free to MU campus, to others for purchase, 2002. http://wwwlib.umi.com/cr/mo/fullcit?p3060136.
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Liavoga, Allan Bright. "D-xylose produced from wheat straw by acid and enzyme catalyzed hydrolysis, and the purification of xylitol /." Search for this dissertation online, 2006. http://www.lib.umi.com/cr/ksu/main.
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Biemi, Flinle Danielle. "Effectiveness of Mandated Folic Acid and Iron Fortification of Wheat Flour on Anemia in Children of Ivory Coast." Digital Archive @ GSU, 2013. http://digitalarchive.gsu.edu/nutrition_theses/44.
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Purpose: Anemia in children is a major Public Health problem in developing countries such as Ivory Coast. The fortification of wheat flour with iron and folic acid has been mandated in this country in 2007. To date, there are no studies conducted to assess the effectiveness of these fortification efforts. Therefore, the purpose of this study was to determine if mandated iron and folic acid fortification of wheat flour has reduced the prevalence of anemia in Ivory Coast children.
Methods: The study was conducted at the pediatric unit of the university hospital of Treichville, one of the 3 main hospitals of Abidjan, the largest city of Ivory Coast. The medical records of 467 children from 5 to 14 years old were analyzed. The period from January 1st 2004 to December 31st 2006 was considered as pre-fortification period and the period from January 1st 2008 to December 31st 2010 was regarded as the post-fortification period. Data for anemia, hemoglobin, hematocrit, red blood cell count, and MCV were compared between pre- and post-fortification periods.
Results: The results showed that there were no statistically significant difference in prevalence of anemia and mean hemoglobin, hematocrit, red blood cells, and MCV between pre and post-fortification periods.
Conclusion: The double fortification of wheat flour with folic acid and iron had no significant impact on anemia in Ivorian children. This is perhaps due to the fact that wheat flour is not widely consumed as rice and rice products are more popular in Ivory Coast population. The Ivorian government perhaps should focus efforts on the fortification of these products.
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Mohamed, Gadija. "The effects of gallic acid on the membrane proteome and antioxidant system of wheat plants under salt stress." University of Western Cape, 2020. http://hdl.handle.net/11394/8252.
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>Magister Scientiae - MSc<br>Salt stress is a major abiotic stress that accounts for huge agricultural losses worldwide, which in turn threaten food security and sustainable agriculture. Salt triggers the excessive production of reactive oxygen species (ROS) which accumulate to levels that become toxic to plants, resulting in cell death and reduced plant growth. Part of the plant’s mechanisms to counteract ROS-induced cell death involves the scavenging ability of the antioxidant defense system to maintain redox homeostasis. Gallic acid (GA) is an antioxidant that has been shown to reduce salt-induced ROS in legume plants. However, its effects on wheat plants have not been elucidated. This study thus investigated the role of exogenous GA (250 μM) on the physiological responses and antioxidant system of wheat plants under salt stress (150 mM). In addition, this study also investigated how GA and salt stress influenced changes in the membrane proteome of wheat plants using LC-MS proteomic analysis.<br>2022
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Schwebach, Catherine Suzanne. "Historical and Modern Hard Red Spring Wheat Comparison: Analysis of Proximate, Enzyme Activity, Phenolic Acid, and Starch Properties." Thesis, North Dakota State University, 2016. https://hdl.handle.net/10365/27985.
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Some claim modern wheat is biochemically different from historic wheat and contributes to chronic diseases. This research was necessary to determine if any significant differences existed between historic and modern hard red spring (HRS) wheat in several physical and chemical components. Thirty HRS cultivars were grown in the same year and location and underwent laboratory analysis. In relation to release year, significant (P<0.05) differences were found for ash content (AC), phosphorous, potassium, zinc, arabinose-to-xylose ratio, enzyme activities, and phenolic acids in whole wheat, AC, and ?-amylase and xylanase activities in white flour, and total starch in bread. The remaining parameters displayed no significant (P>0.05) differences in correlation to release year, including starch digestibility. The majority of results indicate no significant biochemical variations between the historic and modern HRS cultivars. Parameters that demonstrated differences have the potential to affect consumer health and nutrition, but are dependent on bioavailability and consumer choice.
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Ndolo, Victoria Uchizi. "Characterisation of chemical components in manually isolated aleurone and associated layers from maize, wheat and barley kernels." Elsevier, 2013. http://hdl.handle.net/1993/30914.
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Health benefits related to consumption of whole grains have been attributed in part to phytochemical and micronutrient composition. Understanding the composition, structure and distribution of these components in different cereal grains is of potential importance in aiding the selection of whole grains and their processed fractions for inclusion in the diet, and as ingredients in development of new food products. The aim of this research was to characterise the chemical components in the botanical fractions of yellow corn, barley, wheat. Manual separation, a tedious and laborious technique that yields pure fractions, suitable for compositional analysis, was used to separate whole grains into pericarp, aleurone layer, germ and endosperm fractions. Component identification and quantification of tissue components was accomplished by several techniques. The study also explored the possibility of using spectral characteristics fluorescence intensity values to provide rapid estimates of the concentrations and distribution of ferulic acid (FA), a major phenolic compound in cereal grains. While composition of phenolic acids and carotenoids was similar, the distribution was significantly different (P < 0.05) among cereal types and grain fractions. Phenolic acids were concentrated in pericarp and aleurone fractions, followed by the germ and the endosperm had the lowest levels. Yellow corn exhibited the highest values. Carotenoids, lutein and zeaxanthin were concentrated in the germ and aleurone layer of wheat and barley while in yellow corn it was in the endosperm and aleurone layer. This is the first study to report on carotenoid composition of aleurone fractions. Mineral elements, thiamine and niacin were higher in wheat aleurone than in purple barley and yellow corn aleurone layers. These findings suggest that yellow corn aleurone layers have potential as a functional food ingredient despite the low micronutrient content. A positive, significant correlation (r= 0.421, p < 0.0001) was found between fluorescence intensity values and ferulic acid concentration. Thus, fluorescence intensity profiles are a promising approach for rapid assessment of FA concentration in grain in-situ. This work has provided information that would act as a database for selection of cereal fractions and guide the miller to obtain grain fractions with enriched levels of phytochemicals and micronutrients.<br>February 2016
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Rushowski, Clare Elizabeth. "A study of pathogenicity and amino acid metabolism in Stagonospora nodorum." Thesis, University of Bristol, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.390793.
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Kareem, Fakhriya Mohammed. "The influence of exogenously applied 'anti-stress' agents in the upregulation of the drought response in Iraqi wheat varieties." Thesis, University of Plymouth, 2017. http://hdl.handle.net/10026.1/10667.
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Bread wheat (Triticum aestivum L.) is one of the most important cereal crops grown in the world. It has great importance because it constitutes a major source of carbohydrate for more than one third of the world’s population (Budak et al., 2013). In the last three decades, drought conditions are becoming more widespread in wheat production areas including Europe, Australia and Asia, and it is considered a major cause of reduced wheat growth and productivity in most developing countries with semi-arid climates. Drought constitutes the most important threat for wheat production in Iraq and especially for the Kurdistan Regional Governate owing to the limited source of water during at least some part of the growing period. Because wheat is considered a staple food and has economic importance for the Kurdistan Regional Government research is needed to determine the production capacity of Iraqi wheat varieties under drought stress and the potential for the maximization of the drought tolerance response. The soil moisture holding capacity of the intended growing medium was measured gravimetrically in pots with and without wheat plants and correlated with the soil capacitance measured using a TDR Theta Probe (Delta-T Devices). This was used to determine the available water content of the soil (AWC) and to control and manage the watering regimes during drought studies. The results of a study of the response of different cultivars of Iraqi wheat (Triticum aestivum L.) to watering regimes of 70% and 50% showed that drought stress had a significant effect on the biomass and yield traits especially tiller number and stem bundle weight compared to normal conditions. The highest significant difference was observed for cv. Tamooz 2 in comparison to Adana 99, but there was a little difference between cvs. Rizgary and Sham 6. The effect of the exogenous application of salicylic acid (SA) and molybdenum (Mo) on drought tolerance of cvs. Tamooz 2 and Adana 99, showed that Tamooz 2 had higher values for growth characteristics and higher yield potential when sprayed with a lower concentration of SA (1.44 mM) under well-watered conditions in comparison with Adana 99. The effect of spraying variety Tamooz 2 with SA at different growth stages indicated that biomass production and yield components (the number of spikes/pot, grain dry weight and average 1000 grain dry weight) significantly increased at both stem+flower as well as leaf+stem+flower sprayings for plants subjected to drought. Also, SA treatments at stem extension and flowering had a positive effect on the up-regulation of the drought response gene CBF/DREB under drought stress conditions. These findings indicate that agronomic treatments with exogenous applications of salicylic acid and molybdenum could help to reduce the effects of drought in the field.
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Wong, H. M. "Probing the interactions between iron nutrition, salinity and ultraviolet-B radiation on the physiological responses of wheat (Triticum aestivum L.)." Diss., Lincoln University, 2009. http://hdl.handle.net/10182/1327.
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When plants are exposed to multiple environmental stress factors, one form of stress can affect the response to another stress. This study used seedlings of a new cultivar of wheat(Triticum aestivum L. cv. 1862), grown under factorial combinations of two levels of ultraviolet-B (UV-B)radiation, two salinity regimes and two levels of iron treatment in chelator-buffered nutrient solutions in a growth chamber. A number of morphological and physiological measurements were made. The accumulation of chlorophyll, UVabsorbing compounds and proline in shoots, as well as phytosiderophores (PSs) in root exudates were measured. Feed value measurements included crude protein, water-soluble carbohydrates, acid detergent fibre and Fe in shoots and roots. After 21 days of stress exposure, results showed that Fe deficiency and NaCl stress generally decreased plant growth and function as well as nutritive value, but increased plant biochemical protection traits such as proline accumulation (16.3 fold under salinity stress) and release of PSs (2.4 fold under Fe deficiency). Interestingly, UV-B radiation affected belowground parameters, inducing a 47% reduction in PS release, together with decreasing root DM by 9% and Fe concentration in roots by 7%. When Fe deficiency and NaCl stress were combined, the results showed a decrease in PS release by 3.5 fold compared to unstressed plants. UV-B radiation synergistically increased UV-absorbing compound levels in combination with Fe deficiency, compared to plants grown under optimal Fe levels. This stress combination also resulted in a cumulative effect by decreasing Fe concentration in shoots and roots. However, salt stress did not interact with UV-B radiation for any of the traits measured. In addition, some three-way interactions were noted, with the Fe x NaCl x UV-B stress combination slightly decreasing PS release and resulting in a cumulative effect by decreasing Fe concentration in roots. In conclusion, this study found that aboveground stress factors such as UV-B can affect important aspects of belowground plant function, and that Fe deficiency can interact with UV-B and salinity stress in modifying plant responses to either stress alone.
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McManus, Paul. "Rhizosphere Interactions Between Copper Oxide Nanoparticles and Wheat Root Exudate in a Sand Matrix; Influences on Bioavailability and Uptake." DigitalCommons@USU, 2016. https://digitalcommons.usu.edu/etd/5058.
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Copper oxide nanoparticles (NPs) are used in an expanding range of industries including a potential for agricultural applications as a fungicide. Accidental spills or misapplication of CuO NPs may lead to soil contamination. Plant roots exude a wide range of organic chemicals for bioprotection and to enhance bioavailability of nutrients. Many of these chemicals are metal chelators that may increase the solubility of CuO NPs, thus enhancing the impact of these NPs on plants. This work was directed towards understanding which plant exudates force increased solubility of CuO NPs and to determine if the level of NP in the growth matrix drives a feedback effect, regarding composition and quantity of exudates.
Wheat seedlings (Triticum aestivum cv Deloris) were grown in a sand matrix for 10 days after 3 days of germination. The sand was amended with sublethal doses of CuO NPs from 0 to 300 mg Cu/kg dry sand. Sand was selected as the solid growth matrix as a proxy for soil in terms of plant root morphology, mechanical impedance and water stress, while providing a low background of dissolved organic carbon for the isolation of root exudates. After plant growth, the pore water was collected from the sand by vacuum filtration and analyzed.
By coupling analytic techniques including Triple Quad Mass Spectroscopy and ion chromatography with geochemical modeling, we have identified citrate and the phytosiderophore, deoxymugineic acid (DMA) as chelators that drove the majority of dissolution of CuO NPs, especially DMA at higher CuO NP doses. Altered biogeochemistry within the rhizosphere was correlated with increased plant uptake of Cu and bio-response via exudate type, quantity and metal uptake. Exposure of wheat to CuO NPs lead to dose-dependent reduction in Fe, Ca, Mg, Mn and K in roots and shoots. This work is relevant to growth of commercially important crop wheat in the presence of CuO NPs as a fertilizer, fungicide or a pollutant.
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Dromantienė, Rūta. "Aminorūgščių panaudojimas žieminių kviečių biologinio potencialo didinimui." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2011. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2011~D_20110628_111732-34497.
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Darbo tikslas – nustatyti aminorūgščių, esančių skystųjų amidinio azoto trąšų sudėtyje, panaudotų papildomam žieminių kviečių tręšimui per lapus poveikį augalų biologiniam potencialui. Ginamieji disertacijos teiginiai: 1. Aminorūgščių trąšos skatina žieminių kviečių lapų fotosintezės aktyvumą bei didina fotosintetinių rodiklių parametrus. 2. Skirtingų aminorūgščių koncentracijų tirpalai, naudojami įvairiais augalų vystymosi tarpsniais, nevienodai įtakoja žieminių kviečių grūdų derlingumą. 3. Aminorūgštys, naudojamos tręšimui per lapus, teigiamai veikia žieminių kviečių grūdų kokybę bei baltymų ir aminorūgščių kiekybinę ir kokybinę sudėtį.<br>Aim of the work The study was designed to establish the effects of amino acids, present in the composition of liquid amide nitrogen fertilizers, applied as additional foliar feeding on winter wheat. Proposition to be defended: 1. Amino acid fertilization promotes winter wheat leaf photosynthetic activity and increases parameters of photosynthetic indicators. 2. Different concentrations of amino acids applied at various plant growth stages highlight the differences of their efficacy for winter wheat grain yield. 3. Foliar–applied amino acids positively affect winter wheat grain quality and quantitative and qualitative composition of proteins and amino acids.
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Abebaw, Yemisrach Melkie [Verfasser]. "Ectopic expression of a Vicia faba amino acid permease1 (VfAAP1) improves grain yield and stimulates seedling root growth in wheat (Triticum aestivum) / Yemisrach Melkie Abebaw." Halle, 2017. http://d-nb.info/1129174379/34.
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Johansson, Madelene. "Analytical and nutritional aspects of folate in cereals /." Uppsala : Dept. of Food Science, Swedish University of Agricultural Sciences, 2005. http://epsilon.slu.se/200507.pdf.
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Rudjito, Reskandi Chastelia. "Pilot scale process for polysaccharide extraction and fractionation from cereal by-products." Thesis, KTH, Skolan för bioteknologi (BIO), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-215022.
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Kupiainen, L. (Laura). "Dilute acid catalysed hydrolysis of cellulose – extension to formic acid." Doctoral thesis, Oulun yliopisto, 2012. http://urn.fi/urn:isbn:9789526200033.
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Abstract New methods are being sought for the production of chemicals, fuels and energy from renewable biomass. Lignocellulosic biomass consists mainly of cellulose, hemicellulose and lignin. Cellulose and hemicellulose can be converted to their building blocks, i.e. sugars, via hydrolysis. This thesis is focused on glucose production from cellulose by dilute acid hydrolysis. Acid hydrolysis has the drawback of limited glucose yields, but it has the potential to become a short-term solution for biochemical production. During acid hydrolysis, the cellulose chain is split into glucose, which undergoes further decomposition reactions to hydroxymethylfurfural, levulinic acid, formic acid and by-products like insoluble humins. The present thesis aims to increase our knowledge on complicated acid-catalysed hydrolysis of cellulose. Glucose decomposition and cellulose hydrolysis were studied independently in laboratory experiments. Kinetic modelling was used as a tool to evaluate the results. The effect of the hydrogen ion on the reactions was evaluated using formic or sulphuric acid as a catalyst. This thesis provides new knowledge of cellulose hydrolysis and glucose decomposition in formic acid, a novel catalyst for high-temperature dilute acid hydrolysis. Glucose yields from cellulose hydrolysed in formic or in sulphuric acid were comparable, indicating that a weak organic acid could function as a cellulose hydrolysis catalyst. Biomass fibres in the form of wheat straw pulp were hydrolysed more selectively to glucose than a model component, microcrystalline cellulose, using formic acid. Glucose decomposition took place similarly in formic and sulphuric acid when the temperature dependence of the hydrogen ion concentration was taken into account, but a significant difference was found between the reaction rates of cellulose hydrolysis in formic acid and in sulphuric acid. The observations can be explained by changes in the cellulose hydrolysis mechanism. Thus, it is proposed in this thesis that side-reactions from cellulose to non-glucose compounds have a more significant role in the system than has earlier been understood<br>Tiivistelmä Uusia menetelmiä etsitään kemikaalien, polttoaineiden ja energian valmistamiseen uusiutuvasta biomassasta. Eräs biomassa, ns. lignoselluloosa, koostuu pääasiassa selluloosasta, hemiselluloosasta ja ligniinistä. Selluloosa ja hemiselluloosa voidaan muuttaa hydrolyysin avulla niiden rakennuspalikoikseen eli sokereiksi. Tämä väitöskirja keskittyy glukoosin tuottamiseen selluloosasta laimean happohydrolyysin menetelmällä. Happohydrolyysi kärsii rajoittuneesta glukoosin saannosta, mutta sillä on potentiaalia tulla lyhyen aikavälin ratkaisuksi biokemikaalien tuotannossa. Happohydrolyysin aikana selluloosaketju pilkkoutuu glukoosiksi, joka reagoi edelleen hajoamisreaktioiden kautta hydroksimetyylifurfuraaliksi, levuliini- ja muurahaishapoiksi ja kiinteäksi sivutuotteeksi. Tämän tutkimuksen tavoitteena on kasvattaa ymmärrystämme monimutkaisesta happokatalysoidusta selluloosan hydrolyysistä. Glukoosin hajoamista ja selluloosan hydrolyysiä tutkittiin erikseen laboratoriokokein. Kineettistä mallinnusta käytettiin työkaluna arvioimaan tuloksia. Vety-ionien vaikutus reaktioihin arvioitiin käyttämällä muurahais- ja rikkihappoja katalyytteinä. Tämä väitöskirja antaa uutta tietoa selluloosan hydrolyysistä ja glukoosin hajoamisreaktioista muurahaishapossa, joka on uusi katalyytti korkean lämpötilan laimean hapon hydrolyysissä. Glukoosisaannot muurahaishappo-hydrolysoidusta selluloosasta olivat vertailukelpoisia vastaaviin rikkihappo-hydrolyysi saantoihin. Tämä viittaa siihen, että heikko orgaaninen happo voisi toimia selluloosahydrolyysin katalyyttinä. Kun katalyyttinä käytettiin muurahaishappoa, vehnän oljesta tehdyt kuidut hydrolysoituivat selektiivisemmin glukoosiksi kuin mallikomponenttina toimineen mikrokiteisen selluloosan. Kun vetyionikonsentraation lämpötilariippuvuus otettiin huomioon, glukoosi hajosi samalla tavalla sekä muurahais- että rikkihappokatalyytissä, mutta merkittävä ero havaittiin selluloosahydrolyysin reaktionopeudessa. Havainnot voidaan selittää selluloosahydrolyysin mekanismissa tapahtuvilla muutoksilla. Väitöskirjassa esitetään, että sivureaktioilla selluloosasta ei-glukoosi-tuotteiksi on merkittävä vaikutus systeemiin
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Araújo, Michel Mozeika. "Efeito do processamento por ionização, calor e micro-ondas na degradação do ácido fólico." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/85/85131/tde-29062012-134537/.
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Os folatos, vitaminas hidrossolúveis do grupo B estão envolvidos em importantes processos bioquímicos como a síntese e reparação de DNA. O metabolismo humano não é capaz de sintetizar folatos e necessita obtê-los da dieta. O ácido fólico (AF), vitâmero sintético e estável dos folatos, é usado para a fortificação de alimentos como farinha de trigo em função do baixo custo e grande biodisponibilidade. O AF compreende uma pterina, um ácido p-aminobenzóico e um ácido glutâmico. É um composto sensível, facilmente degradado em solução aquosa por luz ultravioleta e visível. O tratamento por ionização de alimentos elimina ou reduz patógenos e insetos, aumenta o tempo de estocagem e a vida de prateleira dos alimentos. A irradiação de alimentos utiliza elétrons acelerados, raios gama ou raios X. Os objetivos deste estudo foram avaliar os efeitos dos tratamentos com feixe de elétrons, térmico em estufa e em forno micro-ondas na degradação do AF em solução, suspensão e pó. Também foi desenvolvido um método de extração por solvente pressurizado do AF de farinha de trigo fortificada e de pães. Os diferentes processamentos degradaram o AF e os principais produtos de degradação foram identificados por LC/MS/MS como sendo: 6- carboxipterina (PCA), ácido p-aminobenzóico (PABA), p-aminobenzoil-L-ácido glutâmico (pABGA) e ácido pteroico (PA). Em soluções de AF irradiadas foram identificados novos radioprodutos: n-(4-nitrobenzoil)-L-ácido glutâmico (pNBGA), xantopterina (XA) e 2-amino-6-(hidroximetil)pteridina-4(1H)-one (AHMP). Uma extração completa do AF por solvente pressurizado foi realizada com sucesso em amostras de farinha de trigo fortificada e pães em apenas 15 minutos. A panificação reduziu em até 57% o teor de AF no produto final. Por outro lado, a irradiação de farinha de trigo fortificada com doses de radiação até 10 kGy não alterou o conteúdo de AF. Esta tecnologia mostrou-se eficaz para tratamento de farinha de trigo e poderia ser utilizada como medida fitossanitária.<br>Folates, water soluble vitamins of B group, are involved in important biochemical processes such as DNA synthesis and repair. The human metabolism is not able to synthesize folate and needs to get them from the diet. Folic acid, a synthetic and stable folate vitamer, is used in food fortification such as wheat flour due to the low cost and high bioavailability. Folic acid is composed of a pterin, the p-aminobenzoic acid and glutamate. This sensitive compound is easily degraded in aqueous solution by ultraviolet and visible light yielding various by-products. Ionizing radiation treatment of food reduces or eliminates pathogens and insects, increases food shelf life and storage. Irradiation is a food preserving process which uses accelerated electrons, gamma rays or X-rays. The objectives of this study were to evaluate the effects of electron beam treatment, heat treatment in oven and microwave in folic acid degradation in solution, in suspension and in powder. A pressurized solvent extraction method was also developed to folic acid fortified wheat flour and bread. The different processing degraded folic acid and the main degradation products were identified by LC/MS/MS as 6-carboxipterin (PCA), p-aminobenzoic acid (PABA), p-aminobenzoyl-L-glutamic acid (pABGA) and pteroic acid (PA). In irradiated folic acid solutions were identified new radioproducts: n-(4-nitrobenzoyl)-L-glutamic acid (pNBGA), xanthopterin (XA) and 2-amino-6-(hydroxymethyl)-pteridine-4(1H)-one (AHMP). A complete extraction of folic acid by pressurized solvent extraction was successfully performed on samples of fortified wheat flour and bread in just 15 minutes. Bread manufacturing reduced up to 57% folic acid content in the final product. Irradiation up to 10 kGy did not alter folic acid content of fortified wheat flour. Irradiation technology proved to be effective for the treatment of fortified wheat flour and could be used as a phytosanitary measure.
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Barunawati, Nunun Verfasser], Nicolaus von [Akademischer Betreuer] [Wirén, Edgar [Akademischer Betreuer] Peiter, and Klaus [Akademischer Betreuer] Humbeck. "Iron and zinc translocation from senescent leaves to grains of wheat (Triticum aestivum cv. Akteur)in response to nitrogen fertilization and citric acid application / Nunun Barunawati. Betreuer: Nicolaus Wirén ; Edgar Peiter ; Klaus Humbeck." Halle, Saale : Universitäts- und Landesbibliothek Sachsen-Anhalt, 2012. http://d-nb.info/1027703291/34.
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Barunawati, Nunun [Verfasser], Nicolaus von [Akademischer Betreuer] Wirén, Edgar [Akademischer Betreuer] Peiter, and Klaus [Akademischer Betreuer] Humbeck. "Iron and zinc translocation from senescent leaves to grains of wheat (Triticum aestivum cv. Akteur)in response to nitrogen fertilization and citric acid application / Nunun Barunawati. Betreuer: Nicolaus Wirén ; Edgar Peiter ; Klaus Humbeck." Halle, Saale : Universitäts- und Landesbibliothek Sachsen-Anhalt, 2012. http://nbn-resolving.de/urn:nbn:de:gbv:3:4-8708.
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Prado, Guilherme Cervi. "Study of reaction parameters in ball mill in the Synthesis of aryl(heteroaryl)-1h-pyrazoles." Universidade Federal de Santa Maria, 2012. http://repositorio.ufsm.br/handle/1/10505.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico<br>In order to eliminate the problems related to deficient intake of vitamins folate class, many food products are being subjected to the enrichment process. Among them, all types of wheat flour must be enriched with folic acid. Therefore, it is evident the need of analytical methods for routine able to effectively determine the levels of folic acid in enriched matrix. The objective of this work was the development and validation of a rapid method for determination of folic acid added to wheat flour, using the technique of high performance liquid chromatography with UV detection. Folic acid was separated using a C8 column. Was used for elution gradient mobile phase with water acidified with glacial acetic acid (pH 2.8) and acetonitrile. Detection was performed with a diode array detector employing a wavelength of 290 nm. External standard was used for quantification. Vitamin matrix was extracted with aqueous potassium hydroxide, 0.1 mol L-1 and aqueous sodium tetraborate 0.04 mol L-1 pH 8.5, followed by cleaning step of the extract of the sample through SPE using SAX cartridges. The method was efficient, with recovery values between 96 and 99%, RSD from 1.3 to 3.8% and LOD and LOQ of 0.28 and 0.937 mg kg-1, respectively. In the analysis of real samples of five brands tested, only one brand presented concentration of folic acid above the minimum required by law.<br>Com o objetivo de suprimir os problemas relacionados à deficiência de ingesta de vitaminas da classe dos folatos, muitos produtos alimentícios estão sendo submetidos ao processo de enriquecimento. Entre eles, todos tipos de farinha de trigo devem ser enriquecidos com ácido fólico. Portanto, fica evidenciada a necessidade de métodos analíticos para a rotina capazes de determinar com eficácia os níveis de ácido fólico na matriz enriquecida. O objetivo deste trabalho foi o desenvolvimento e validação de um método rápido para determinação de ácido fólico adicionado a farinha de trigo, através da técnica de cromatografia líquida de alta eficiência com detector espectrofotométrico. O ácido fólico foi separado utilizando-se coluna de C8. Utilizou-se eluição por gradiente na fase móvel, com água acidificada com ácido acético glacial (pH 2,8) e acetonitrila. A detecção foi efetuada com detector por arranjo de diodos empregando o comprimento de onda de 290 nm. Foi utilizada padronização externa para quantificação. A vitamina foi extraída da matriz com solução aquosa de hidróxido de potássio 0,1 mol L-1 e solução aquosa de tetraborato de sódio 0,04 mol L-1 de pH 8,5; seguida por etapa de limpeza do extrato da amostra através de SPE, utilizando cartuchos de SAX. O método mostrou-se eficiente, com valores de recuperação entre 96 e 99%, RSD de 1,3 a 3,8% e LOD e LOQ de 0,28 e 0,937 mg kg-1, respectivamente. Nas análises das amostras reais, das cinco marcas analisadas, somente uma marca apresentou concentração de ácido fólico acima do mínimo exigido pela legislação.
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Vargas, Taís Dufau de. "Avaliação de parâmetros da qualidade da carne de frangos alimentados com farelo de trigo e fitase ou com adição de ácido fítico na dieta." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2012. http://hdl.handle.net/10183/77654.
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Com o objetivo de avaliar a qualidade da carne de frangos recebendo dietas com inclusão de ácido fítico (AF) ou com farelo de trigo (FT) e adição ou não de fitase, foram utilizados 216 frangos de corte Cobb 500®, machos, de 22 a 35 dias de idade. O delineamento experimental foi inteiramente casualizado com 6 tratamentos e 6 repetições com 6 animais cada. Foram testadas 6 dietas: 1- dieta controle (a base de milho e farelo de soja); 2- dieta controle com adição de AF; 3- dieta com 25% de FT e sem fitase; 4- dieta com 25% de FT + 6-fitase/2500 FTU/g (fitase A); 5- dieta com 25% de FT + 6-fitase/5000 FTU/g (fitase B); 6- dieta com 25% de FT + 3-fitase/5000 FTU/g (fitase C). Os parâmetros avaliados foram: peso da carcaça, peso e rendimento dos cortes de peito, de coxa e de perna de frango, pH inicial e final da carne, cor, lipídeo total, colesterol total (CT), oxidação lipídica (TBARS), perda de peso por descongelamento (PPD), perda de peso por cocção (PPC) e força de cisalhamento (FC). Os resultados indicaram não haver interação das diferentes dietas para as respostas de: peso da carcaça, peso e rendimento dos cortes, lipídio total, PPD, PPC e pH inicial, ou seja, todas estas variáveis mostraram-se semelhantes entre as dietas testadas, conferindo uma carne de igual qualidade para estes parâmetros. Entretanto, o pH final da carne do peito foi menor para os frangos alimentados com a dieta controle (com milho e soja) que, ainda mostrou na avaliação de cor, um peito de frango com teor de amarelo (b*) mais intenso do que os apresentados pelas outras dietas. Embora tenham sido diferentes, esses dois parâmetros apresentaram valores que são considerados normais para peito de frango. A adição de AF na dieta controle promoveu um efeito muito importante na redução do colesterol total (CT) e da oxidação lipídica (TBARS) da carne de frango. E a inclusão de FT na dieta, em relação à dieta basal de frangos, ainda refletiu em teores de CT semelhantes ou menores aos obtidos por esta última dieta (dieta controle). Porém, nos valores de TBARS não ocorreu a mesma resposta, pois o FT só conseguiu ter efeito na inibição da oxidação lipídica (em relação à dieta controle) quando ele foi adicionado de fitase (mais especificamente uma 6-fitase de E. coli, definida como fitase B no presente estudo). Ao mesmo tempo, a adição desta fitase na dieta com FT, foi a que refletiu na maior força de cisalhamento (FC) dos peitos de frango entre as distintas dietas. Entretanto, o valor de FC obtido nesta dieta e nas outras, está dentro do valor considerado como macio. Ou seja, todas as dietas conferiram em uma carne de textura macia. Contudo, o FT pode ser utilizado em dietas para frangos de corte sem prejudicar as respostas de qualidade de carne. Além disso, o AF parece ser o componente responsável por diminuir o CT e a oxidação lipídica da carne de frango.<br>With the objective to evaluate of meat quality of broilers receiving diets with inclusion of phytic acid (PA) or wheat bran (WB) and addition or not of phytase, were used 216 Cobb 500® broilers, males, from 22 to 35 days old. The experimental design was completely randomized with six treatments and six replicates of six animals each. Six diets were tested: 1- control diet (with corn and soybeans); 2- control diet with addition of PA; 3- diet with 25% WB and without phytase; 4- diet with 25% of WB + 6-phytase/2500 FTU/g (phytase A); 5- diet with 25% of WB + 6-phytase/5000 FTU/g (phytase B); 6- diet with 25% of WB + 3-phytase/5000 FTU/g (phytase C). Were evaluated the parameters: carcass weight, cuts weight and income of chicken breast, of thigh and of on-thigh, initial and final pH of chicken, color, total lipid, total cholesterol (TC), lipid oxidation, (TBARS), weight loss by thawing (WLT), weight loss by cooking (WLC) and shear force (SF). The results showed there is not interaction of the different diets for the answers of: carcass weight, cuts weight and income, total lipid, WLT, WLC and pH initial, that is, all these variables were similar among the diets tested, resulting in an quality equal meat for these parameters. However, the final pH of breast meat was lower in chickens fed the control diet (corn and soybeans) that also showed in the evaluation of color, a chicken breast with content of yellow (b *) more intense than the presented by the other diets. Although have been different, these two parameters had values that are considered normal for chicken breast. The addition of PA in the control diet promoted a significant effect in reducing total cholesterol (TC) and lipid oxidation (TBARS) of chicken meat. And the inclusion of WB in the diet in relation to the chicken basal diet, reflected still in TC levels similar or lower to those obtained by this diet latter (control diet). However, on TBARS values did not occur the same answer, because the WB only managed to have an effect on the inhibition of lipid oxidation (in relation to the control diet) when it was added of phytase (more specifically a 6-phytase from E. coli, defined as phytase B in this study). At the same time, the addition of phytase in the diet with WB, was the which reflected in higher shear force (SF) of the chicken breasts between the different diets. However, the SF value obtained in this diet and on the other is within of the value regarded as tender. That is, all diets resulting in a soft texture meat. However, the WB can be used in diets for broilers without affecting meat quality answers. In addition, the PA seems to be the component responsible for reducing of the TC and lipid oxidation of chicken meat.
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Cony, Stéphanie. "Déconstruction raisonnée par voie enzymatique des hétéroxylanes de la biomasse lignocellulosique et purification éco-compatible des différentes fractions fonctionnelles." Thesis, Reims, 2017. http://www.theses.fr/2017REIMS020.
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Les co-produits agricoles, son et paille de blé, sont riches en arabinoxylanes (AX) qui après hydrolyse peuvent fournir des molécules pour des usages variés: xylo-oligosides (prébiotiques), xylose (xylitol), acide férulique (vanilline, antioxydant). L’étude a visé à mettre en place un procédé intégré et éco-compatible, depuis l'hydrolyse enzymatique des AX du son de blé jusqu'à la purification de l'acide férulique. Des cocktails hémicellulasiques produits par culture de la bactérie Thermobacillus xylanilyticus sur paille ou son de blé et mis en œuvre dans des conditions variées ont permis de libérer des glucides (mono- et oligomères) et de l’acide férulique. Afin d’augmenter la monomérisation, deux nouvelles β-xylosidases ont été produites à partir de T. xylanilyticus et caractérisées. Elles ont été testées pour complémenter des cocktails hémicellulasiques complexes issus de T. xylanilyticus et étudiées en mélange avec une xylanase et une arabinosidase pures. Le choix d’une résine anionique faible sous forme base libre pour séparer les fractions glucidique et phénolique et purifier l’acide férulique s’est également inscrit dans une démarche d’éco-conception : la résine Amberlyst A21 a montré une bonne affinité pour l’acide férulique et sa régénération a libéré une fraction très concentrée. La déminéralisation préalable de l’hydrolysat par électrodialyse a permis d’accroître la capacité de la résine pour l’acide et la pureté de la fraction récupérée, potentiellement cristallisable<br>Agriculture by-products (wheat bran and straw) are rich in arabinoxylans (AX). These polymers composed of a main chain of β-(1,4) linked xylose ramified by arabinose and ferulic acid, are sources of molecules for various applications: xylooligosaccharides as prebiotics, xylose to synthesize xylitol, a non-cariogenic sweetener, or ferulic acid as a precursor of vanillin or an antioxidant molecule for packaging applications. The aim of this work was to set up an eco-friendly process ranging from wheat bran AX hydrolysis to ferulic acid purification.Hemicellulasic cocktails obtained by growing Thermobacillus xylanilyticus on wheat straw or wheat bran were implemented in various conditions. They released a carbohydrate fraction (mono- and oligosaccharides) and ferulic acid. In order to increase the monomerization, two new β-xylosidases were grown from T. xylanilyticus and characterized. They were tested to supplement the complex hemicellulasic cocktails from T. xylanilyticus and studied in mixture with a pure xylanase and a pure arabinosidase.The choice of a weak anionic resin under free base form to separate the glucidic and the phenolic fractions and to purify ferulic acid was also driven by environnement purposes: Amberlyst A21 resin showed a good affinity for ferulic acid and regeneration allowed a concentrated fraction of ferulate to be obtained. Prior demineralization by electrodialysis increased the capacity of the resin for ferulic acid and the purity of the recovered fraction, potentially allowing crystallization
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Gonzalez, Karen Vanessa. "Modélisation et commande robuste des systèmes biologiques : exemple de la production d’acide lactique en fermenteur industriel." Thesis, Châtenay-Malabry, Ecole centrale de Paris, 2015. http://www.theses.fr/2015ECAP0044/document.
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Cette thèse de doctorat porte sur l’optimisation du bioprocédé de production d’acide lactique à partir de la farine de blé. L'acide lactique s’avère en effet de plus en plus attractif pour la production de PLA (acide poly lactique), un bio polymère, d’autant plus que différentes matières premières peu coûteuses comme la farine de blé sont désormais utilisées comme sources de carbone pour sa production. Cette thèse comprend trois parties principales. Une première partie propose pour l’optimisation du procédé de transformation du blé un schéma innovant composé de trois étapes successives : une liquéfaction, suivi d’une étape de saccharification et hydrolyse des protéines simultanées (SSPH) et une étape finale de saccharification, hydrolyse des protéines et fermentation simultanées (SSPHF). La deuxième partie s’intéresse à la modélisation de l’étape SSPHF (étape limitante) dans un bioréacteur continu. La détermination des paramètres du modèle ainsi que leur validation sont réalisées à l’aide de campagnes d’essais sur un bioréacteur de 5 L.Enfin, la dernière partie développe la mise en oeuvre de stratégies de commande permettant de maintenir le bioprocédé à son point optimal de fonctionnement. Pour ce faire, du fait de l’absence de capteurs pour la mesure en temps réel des concentrations des variables clé dans le bioréacteur, des estimateurs de ces concentrations ainsi que du taux de production en acide lactique sont tout d’abord élaborés. Des stratégies de commande régulant la concentration d’acide lactique à sa valeur optimale sont ensuite synthétisées et comparées en simulation. Une commande adaptative combinant une commande linéarisante par retour d’état et un estimateur du taux de production en acide lactique est finalement retenue et validée expérimentalement sur un réacteur instrumenté. Cette dernière s’est avérée robuste vis-à-vis des erreurs de modélisation et a permis lors des expériences de doubler la productivité de l’acide lactique<br>This PhD thesis focuses on the optimization of the bioprocess of lactic acid production from wheat flour. Indeed, lactic acid has received much attention for the production of PLA (Poly Lactic Acid), a biopolymer, since different inexpensive raw material such as wheat flour are now used as carbon source for its production. This work was performed in three main steps. In the first step, an innovative wheat transformation process is proposed, whose main steps are the following: a liquefaction followed by a simultaneous saccharification, proteins hydrolysis (SSPH) and and a final simultaneous saccharification, proteins hydrolysis and fermentation (SSPHF). Secondly, the modeling of the SSPHF (limiting step) in a continuous bioreactor is considered. The determination and validation of model parameters is performed by means of experimental campaigns in a 5 L bioreactor.In the last step, the development of control strategies to maintain the process at its optimal operating point is considered. To do so, due to the absence of sensors for real-time measurement of the concentrations of key variables of the bioreactor, estimators of these concentrations and of the lactic acid production rate are first developed. Then, control strategies for regulating the lactic acid concentration at its optimal value are designed and compared in simulation. An adaptive control combining a state feedback linearizing control and an estimator of the lactic acid production rate is finally chosen to be experimentally validated on an instrumented reactor. This strategy showed good robustness features with respect to modeling mismatches and was able during experiments to increase twice the lactic acid productivity
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Chabrat, Elodie. "Développement de nouvelles formulations d'agromatériaux thermoplastiques par mélange en extrudeur bivis de céréales et de polymères issus de ressources renouvelables." Thesis, Toulouse, INPT, 2012. http://www.theses.fr/2012INPT0036/document.
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Dans ce travail de thèse, nous nous sommes intéressés au mélange de la farine de blé et du poly(acide lactique). La farine de blé, qui est composée principalement d'amidon, a été thermoplastifiée en extrudeur bivis par l'effet conjugué de la chaleur et du cisaillement en présence de plastifiants. Le poly(acide lactique) est, quant à lui, le polyester biodégradable le plus répandu à l'heure actuelle. Le mélange de ces deux phases est thermodynamiquement immiscible et peu compatible, différents leviers sont testés afin d'améliorer la qualité du mélange. Une première partie de ce travail repose sur la recherche de conditions optimales pour la transformation et le mélange des matières premières. L'extrusion bivis est utilisée à la fois pour plastifier l'amidon et pour assurer un bon mélange entre les phases. Le profil de vis et les différents équipements sont donc choisis en conséquence. Différents paramètres classiques de l'extrusion bivis sont étudiés : le profil de vis, le profil de température, le taux de remplissage… L'étude de la formulation, notamment des plastifiants utilisés pour la plastification de l'amidon mais également l'utilisation de compatibilisants pour améliorer l'interface amidon/PLA est traitée en deuxième partie. L'acide citrique est testé à la fois comme plastifiant et comme compatibilisant. Ces investigations nous ont permis de mettre au point différents grades intéressants répondant à des applications industrielles distinctes : injectabilité, souplesse, rigidité…<br>In this work, we have been interested in blending wheat flour and poly(lactic acid). Wheat flour, which is mainly constituted of starch, has been transformed with plasticizers in a twin-screw extruder with the effect of heat and shear. Poly(lactic acid) is the main biodegradable polyester in the world nowadays. These two phases are thermodynamically immiscible and not very compatible, different ways are tried to improve the blend quality. A first part of this work lies on the search of optimal conditions to transform and blend the raw materials. Twin-screw extrusion is used to pasticize starch and to ensure a good blending between the two phases. Screw design and different equipments have been chosen for this purpose. Classical twin-screw parameters have been studied: screw design, temperature profile, filling ratio… The study of the formulation, more particularly of plasticizers for starch plasticization but also of compatibilizers to improve starch/PLA interphase is tackled in a second part. Citric acid is tested as a plasticizer but also as a compatibilizer. These researches have allowed to develop interesting formulations for industrial applications: possibility of processing by injection-molding, flexibility, rigidity…
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Bonilla, Lagos Maria Jeannine. "Desarrollo de films y recubrimientos comestibles bio-activos como soporte de agentes antioxidantes y antimicrobianos." Doctoral thesis, Universitat Politècnica de València, 2013. http://hdl.handle.net/10251/28370.
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RESUMEN
El objetivo de esta tesis fue la obtención y caracterización de
films biodegradables con características antimicrobianas y/o
antioxidantes a partir de quitosano (CH). Para modular sus
propiedades y mejorar su funcionalidad, se estudió la
combinación con otras matrices poliméricas: almidón de trigo
(WS), polivinil alcohol (PVA) y ácido poliláctico (PLA).
Además se incorporaron aceites esenciales (EO) de tomillo (Th)
o albahaca (B), ¿-tocoferol (Tp) y ácido cítrico (CA).
Se evaluó el efecto del tratamiento de homogenización de las
dispersiones formadoras de films (FFD) en films de quitosano
con EO en diferentes proporciones. La microfluidización dio
lugar a una reducción en el tamaño de gota, a una mayor carga
superficial de las mismas y una menor viscosidad de las
dispersiones. Además, intensificó todos los efectos provocados
por la incorporación de EO sobre las propiedades mecánicas de
los films debido a potenciación de las interacciones con el
polímero. A baja proporción de EO, la microfluidización mejoró
las propiedades de barrera al vapor de agua de los films, pero no tuvo un impacto significativo en la permeabilidad al oxígeno.
Los films ejercieron un papel protector frente a la oxidación en
grasa de cerdo. La presencia de EO en los films, a pesar de
aumentar la permeabilidad al oxígeno, dio lugar a una menor
velocidad de oxidación de las muestras (especialmente a alta
humedad relativa), probablemente por el efecto antioxidante de
los componentes de los EO. Los films de quitosano se mostraron
efectivos en el control del deterioro microbiano cuando se
aplicaron en carne de cerdo picada, pero la incorporación de los
EO no mejoró su actividad antimicrobiana.
Se incorporó CH en films de WS en diferentes proporciones. La
adición de CH en cantidades crecientes dio lugar a un aumento
en la viscosidad y estabilidad de las FFD. Ambos polímeros
mostraron un alto grado de compatibilidad lo que dio lugar a una
microestructura homogénea. El aumento de la proporción de CH
dio lugar a films con mejores propiedades mecánicas ya que el
CH pareció inhibir la retrogradación del almidón. Los films
WS:CH dieron lugar a una reducción de la carga microbiana
cuando se aplicaron en muestras de carne de cerdo picada. Se incorporaron diferentes antioxidantes (aceite esencial de
tomillo y albahaca, ácido cítrico y ¿-tocoferol) en films mezcla
de WS (80%) y CH (20%). Los films presentaron una
microestructura heterogénea por la inmiscibilidad de
componentes, principalmente el film con ¿-tocoferol que
presentó separación de fases. Esto llevó asociado una superficie
más rugosa, con menor brillo y, en el caso del ¿-tocoferol, un
color más amarillo. No obstante la incorporación de
antioxidantes conllevó un aumento de la transparencia y una
disminución de la permeabilidad al oxígeno. El CA provocó un
aumento en el módulo de elasticidad y un descenso de la
extensibilidad de los films.
La incorporación de CH en matrices de PVA dio lugar a films
altamente homogéneos, debido a la compatibilidad de ambos
polímeros. Se obtuvieron films más resistentes y rígidos, pero
menos extensibles. Se observó una reducción del grado de
cristalinidad y un aumento de la estabilidad térmica, además de
una reducción de la trasmisión de la luz UV. Así mismo, cuando se aplicaron a muestras de carne de cerdo picada presentaron
una acción antimicrobiana.
La incorporación de CH en una matriz de PLA mediante
extrusión no afectó al comportamiento térmico del PLA ni a su
grado de cristalinidad. Ambos polímeros se mostraron
incompatibles. La reducción del tamaño de las partículas de CH
minimizó el impacto negativo sobre las propiedades mecánicas
y de barrera al vapor de agua. En su aplicación a muestras de
carne de cerdo picada, la presencia de CH mejoró las
propiedades antimicrobianas de los films.<br>Bonilla Lagos, MJ. (2013). Desarrollo de films y recubrimientos comestibles bio-activos como soporte de agentes antioxidantes y antimicrobianos [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/28370<br>TESIS
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Tran, Thi Phuong Thao. "Développement de biocomposites à base de Poly(Acide Lactique) et de balles céréalières : vieillissement des biocomposites et traitement de surface des balles." Thesis, Montpellier 2, 2013. http://www.theses.fr/2013MON20203/document.
Full textAbstract:
Les balles de céréales, à savoir l'enveloppe autour du grain, ont récemment retenu l'attention des scientifiques afin d'entrer dans la formulation de biocomposites. En effet, ces sous-produits de l'agriculture ont un coût négligeable, sont perpétuellement renouvelables et disponibles en volume important dans le Monde et leur fin de vie est assurée par leur biodégradabilité. Leurs compositions chimiques et leurs propriétés thermiques et mécaniques sont similaires à celles des fibres naturelles.Dans cette thèse, deux types de balles de riz et deux types de balles de Petit Epeautre ont été étudiées à travers leur microstructure, leur composition chimique, leurs propriétés mécaniques et thermiques. Les balles ont été incorporées dans une matrice bio-sourcée et biodégradable, à savoir le poly(acide lactique) (PLA) pour donner des biocomposites dont les propriétés d'usage ont été étudiées. Il apparaît que les balles céréalières peuvent devenir un candidat potentiel intéressant pour le renforcement du PLA moyennant une amélioration de l'adhésion à l'interface entre les balles et le PLA.Afin d'améliorer cette interface, les balles ont été traitées par une solution alcaline (NaOH) et par des agents de couplage de type organosilane (3-aminopropyltriéthoxysilane et 3- glycidoxypropyltrimethoxysilane). Le traitement alcalin a permis de retirer une grande partie des hémicelluloses, de la lignine, de la cire et de la silice présentes dans les balles. La dissolution de ces constituants a provoqué une plus forte hygroscopicité des balles et se traduit par de plus faibles propriétés mécaniques des biocomposites. Le couplage traitement alcalin/traitement silane semble apporter une amélioration des performances plus importantes que le traitement silane seul. Ce traitement de surface a davantage d'impact sur la balle de Petit Epeautre que sur la balle de riz.L'évolution des propriétés d'usage des biocomposites à base de balles de riz au cours de différents vieillissements (thermique, hydro-thermique, cyclages hygro-thermiques, UV) a été étudiée. Les résultats montrent que l'évolution microstructurale induite par les vieillissements influence significativement les propriétés des biocomposites. La dégradation des biocomposites se traduit par une diminution de la masse moléculaire moyenne du PLA. La réorganisation de ces macromolécules augmente sensiblement le taux de cristallinité du matériau. Ceci induit un changement de la couleur, de la stabilité dimensionnelle des pièces et des propriétés mécaniques du PLA et des biocomposites qui dépend essentiellement de la température de vieillissement par rapport à la température de transition vitreuse du PLA. Il apparaît que l'ajout de balles accélère la dégradation du PLA. Dans le cas d'un vieillissement hydro-thermique au-dessus de la température de transition vitreuse du PLA, une réduction de cette dégradation a été mise en évidence par l'utilisation de certains traitements de surface des balles<br>The cereal husks, namely the envelope around the grain, have recently attracted the attention of scientists for biocomposites development, because they are low-cost, renewable, biodegradable, and available in abundant volume throughout the world. Their chemical composition and their thermal and mechanical properties are similar to the natural fibers.In this work, two types of rice husk and two types of Einkorn wheat husk were studied through their microstructure, chemical composition, mechanical and thermal properties. The husks have been incorporated into a bio-sourced and biodegradable matrix, namely poly (lactic acid) (PLA) to produce biocomposite which functional properties were studied. It appears that the husks can be good candidates for strengthening the PLA through improved adhesion at the interface between the husks and the PLA.To improve the husks/PLA interface, the husks were treated with an alkaline solution (NaOH) and organosilane coupling agents, such as 3-aminopropyltriethoxysilane and 3 - glycidoxypropyltrimethoxysilane. The alkaline treatment has removed much of hemicelluloses, lignin, wax and silica present in the husks. The dissolution of these components resulted in a higher hygroscopicity of husks and lower mechanical properties of biocomposites. The coupling between an alkaline treatment and a silane treatment seems to provide better properties than the silane treatment alone. This surface treatment has a greater impact on the Einkorn wheat husks than on rice husksThe variations of the functional properties of rice husks based biocomposites during different ageings (thermal ageing, hydro-thermal ageing, hygro-thermal cycled ageing, UV ageing) was studied. The results show that the microstructural changes induced by ageing significantly influence the properties of biocomposites. Biocomposites degradation results in a decrease of the average molecular weight of PLA. The reorganization of these macromolecules significantly increases the degree of crystallinity of the material. This causes a change in color, dimensional stability of devices and mechanical properties of PLA and biocomposites which essentially depends on the ageing temperature regards to the glass transition temperature of PLA. It appears that the addition of husks accelerates the degradation of PLA. In the case of a hydro-thermal ageing performed above the glass transition temperature of the PLA, a reduction of this degradation was demonstrated by the use of specific surface treatments of husks
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Souza, Neto Floriano Soeiro de. "AVALIAÇÃO DO PROCESSO DE ENRIQUECIMENTO DE FARINHA DE TRIGO COM APOIO DO CONTROLE DE PROCESSOS." Universidade Federal de Santa Maria, 2011. http://repositorio.ufsm.br/handle/1/8199.
Full textAbstract:
Government policies in health are directed to preventive measures. In this respect, it
was established in 2002 by the Brazilian Federal government, and also being
controlled in several countries, that iron and folic acid must be added to wheat and
corn flour. The aim of this research was to investigate the wheat flour enrichment
process with folic acid. Were searched twenty-three among the largest flour mills in
Rio Grande do Sul. Sixty (60) samples of wheat flour bought in supermarkets in the
central region of the state of RS were also tested for the dosage of folic acid with
HPLC. The tests were performed in laboratory of the Santa Maria Federal University.
The variation in production methods and inadequate process control were salient.
Only 18.3% of the samples studied were within the present regulatory measures.
Thus, it was observed that the process, despite its importance, has low compliance.<br>As políticas governamentais em saúde estão direcionadas para as medidas
preventivas. Neste sentido, foi estabelecido em 2002 pelo governo federal brasileiro,
e já em execução em vários países, que fossem enriquecidas com ácido fólico e
ferro as farinhas de trigo e milho. O objetivo desta pesquisa foi avaliar o processo de
enriquecimento de farinha de trigo com ácido fólico. Foram pesquisados vinte e três
dentre os maiores moinhos de trigo do Rio Grande do Sul. Foram testadas 60
(sessenta) amostras de farinha de trigo compradas em supermercados da região
central do RS, nas quais foi realizada a dosagem de ácido fólico com HPLC em
laboratório da Universidade Federal de Santa Maria. A variação de métodos de
produção adotados e controle do processo inadequado foram marcantes. Apenas
18,3% das amostras pesquisadas apresentam teores dentro das normativas. Dessa
forma, observou-se que o processo, apesar da sua importância, apresentou baixa
conformidade.
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Souza, Juliane Alves de. "ESTUDO TERMOANALÍTICO, REOLÓGICO E ESTRUTURAL DE AMIDO DE TRIGO MODIFICADO POR UMIDADE E TEMPERATURA CONTROLADAS (HMT)." UNIVERSIDADE ESTADUAL DE PONTA GROSSA, 2014. http://tede2.uepg.br/jspui/handle/prefix/642.
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Previous issue date: 2014-12-12<br>Cereals have an important role in human nutrition. Wheat is one of the most cultivated and consumed cereals in the world being used in the preparation of the enormous diversity of products. The wheat flour fortification with iron and folic acid is obligatory in Brazil in according with current legislation. Starch is a reserve polysaccharide of vegetable consisting essentially of amylose and amylopectin. It is a matter abundant and replaceable material being the main source of carbohydrate in diet human. Starches in their native form have limited features for industrial use so it is important modification aiming to acquire improved stability, rheological properties, paste, gel texture, water retention, among others. The chemical modification, still very used, is not considered as safe a one way of modification, so the physical modification is well regarded by food industry. Heat Moisture Treatment (HMT) in starch is considered a natural method and is conducted with a moisture content of 30% and a maximum temperature of 120 ° C. Were studied native wheat and modified starches with presence and absence of folic acid and iron, by HMT at 121 °C for a period of 1 hour. The effects of HMT were studied using the following techniques: thermogravimetry and derivative thermogravimetry (TG/DTG), differential scanning calorimetry (DSC), x-ray diffraction (DRX), atomic force microscopy (NC-AFM), rapid visco analysis (RVA), the flame atomic absorption spectrometry (FEAA) and reflectance photocolorimetry. From the TG and DTG curves was observed that for the physically treated starches, the values of weight loss for starch in the presence of folic acid iron in the first and third stages decreased and the second increased as increased moisture. The DSC, modified starches, the temperatures at which the event occurred and the enthalpy of gelatinization decreased and the higher the moisture treatment was lower enthalpy. All starches showed bimodal distribution and irregularities in the micro-images of AFM with changes in average diameter and roughness, after physical modification. For all starches DRX peaks did not undergo
pronounced displacement, however there was a decrease in crystallinity after modification. All starches showed high paste temperature and low peak viscosity. Was determined absence iron concentration to starch without folic acid and iron and little change for the presence of starch with these nutrients. With respect to color analysis for all samples studied, there was little variation in color between them, with causing a trend mainly to yellow after modification.<br>Cereais possuem importante papel na alimentação humana. O trigo é um dos cereais mais cultivados e consumidos no mundo sendo utilizado na elaboração de enorme diversidade de produtos. A fortificação da farinha de trigo com ferro e ácido fólico é obrigatória no Brasil de acordo com a legislação vigente. O amido é um polissacarídeo de reserva vegetal constituído basicamente por amilose e amilopectina. É uma matéria prima abundante e renovável sendo a principal fonte de carboidrato na alimentação humana. Amidos na forma nativa possuem características limitadas para uso industrial por isso torna-se importante sua modificação visando adquirir melhor estabilidade, propriedades reológicas, de pasta, textura de géis, retenção de água entre outros. A modificação química, ainda muito utilizada, não é considerada uma forma tão segura de modificação, por isso a modificação física é bem vista pela indústria alimentícia. A modificação por umidade e temperatura controladas (HMT) em amido é considerada um método natural e é conduzida com teor de umidade de até 30% e temperatura máxima de 121 ºC. Foram estudados amidos trigo nativos e modificados, com presença e ausência de ácido fólico e ferro, por HMT a 121°C por um período de 1 hora. Os efeitos do HMT foram estudados utilizando as seguintes técnicas: termogravimetria e termogravimetria derivada (TG/DTG), calorimetria exploratória diferencial (DSC), difração de raios X (DRX), microscopia de força atômica (NC-AFM), análise viscoamilográfica rápida (RVA), espectrometria de absorção atômica com chama (FEAA) e refletância fotocolorimetria. A partir das curvas TG e DTG, observou-se que para os amidos tratados fisicamente, os valores de perda de massa para o amido em presença de ácido fólico e ferro, nas primeiras e terceiras etapas diminuíram e da segunda aumentaram, conforme aumento da umidade. Após a análise de DSC, os amidos modificados, as temperaturas em que ocorreu o evento e o valor da entalpia de gelatinização diminuíram e quanto maior a umidade de tratamento menor foi à entalpia. Os amidos deste estudo apresentaram distribuição bimodal e irregularidades nas microimagens de AFM, com alterações nos diâmetros médios e rugosidade, após a modificação física. Para todos os amidos os picos de DRX não sofreram deslocamento acentuado, porem houve redução da cristalinidade após a modificação. Todos os amidos apresentaram alta temperatura de pasta e baixo pico de viscosidade. Foi determinada ausência de ferro para o amido sem ácido fólico e ferro e pouca alteração para o amido com presença desses nutrientes. Com relação a análise de cor, para todas as amostras estudadas, houve pouca variação de cor entre elas, com tendência ao amarelamento após a modificação.
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Almásyová, Zuzana. "Využití škrobu a glycerinu k přípravě polymerních fólií s řízenou dobou života." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2018. http://www.nusl.cz/ntk/nusl-376797.
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This diploma thesis deals with preparation and testing of biodegradable materials for use in the packaging indrustry. The task of this work is to prepare set of laboratory made films based on wheat starch, glycerol, polyvinyl alcohol with the addition of a suitable additive, which has been selected as citric acid. A suitable composition meeting the requirements of the packaging foils has been found. Quaternary blends from all components achieve the best results. It has been found that citric acid can influence the chemical structure and thus affect the mechanical and thermal properities and also the degree of solubility. The films were characterized in terms of mechanical properities by tensile testing and thermal stability by means of thermogravimetric analysis with respect to the phase structure. The structure was characterized by Fourier transform infrared spectroscopy and confocal laser scanning microscopy. The biodegradability of the film was tested by its solubility in aqueous medium.
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Losi, Lorenzo. "Impact assessment of an innovative process for levulinic acid production from biomass." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019.
Find full textAbstract:
A large part of energy carriers and chemicals of our society come from fossil fuels; due to their critical exploitation and environmental concerns, alternative solutions should be promoted.
The goal of this work is to understand the environmental impacts of different supply chains of levulinic acid production. To enable this comparison, a cradle-to-gate LCA was conducted on different kinds of biomasses, under an innovative thermochemical process called Biofine. The study concerns biomass not only of agri-food origin (corn stover, barley straw, wheat straw), but also deriving from the waste collection supply chain (organic fraction of municipal solid waste).
Results show that biochemicals production from waste-derived biomass represent the lowest environmental impact solution, compared to the supply chain with biomass of agri-food origin. For agri-food biomasses, the impacts deriving from the agricultural phase are orders of magnitude more significant than those of the industrial phase, while the transport phase is the least impacting in absolute terms. For waste-derived biomasses, transport is the most impacting phase of the entire supply chain.
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Nábělek, Jakub. "Vývoj a validace postupu pro izolaci kyseliny ferulové z pšeničných otrub." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2020. http://www.nusl.cz/ntk/nusl-432679.
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This master thesis deals with an optimization of processes of isolation of ferulic acid from wheat bran. Process of isolation based on alkaline hydrolysis from the substance and its adsorption was tested. In the theoretical part were described wheat bran, adsorption proces and used methods. For adsorption were tested five types of adsorbents. Especially these adsorbents: activation carbon (2,53 ± 1,16 mg.l-1), Amberlyst A-21 (105,73 ± 11,87 mg.l-1, Amberlit XAD-16 (241,55 ± 10,42 mg.l-1), Amberlit IRA-900Cl (5,90 ± 0,68 mg.l-1) and Amberlit IRA-96 (189,16 ± 6,49 mg.l-1). As the most efficient adsorbent was determine Amberlit XAD-16. The whole process has underwent detailed optimization in order to maximize the purity of the final product. The isolate was characterized by HPLC and FTIR techniques for ferulic acid and related phenolic acids. Based on FTIR analysis was discovered that the isolate was contamined by proteins. A purification procedure based on deproteination of the raw material before the hydrolysis itself was proposed. As the ultimate solution that eliminated the presence of proteins in the isolate was determine ultrafiltration with capture of molecules with Mw > 10 KDa. Ferulic acid yield from one kilo of wheat bran was 1,00 ± 0,22 g.
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Abdillahi, Houssein. "Propriétes barrière et mécaniques d'agromatériaux thermoplastiques à base de farine de blé et de polyesters biosources et biodégradables." Thesis, Toulouse, INPT, 2014. http://www.theses.fr/2014INPT0027.
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Des produits de consommation de première nécessité aux produits les plus fortuits, l'emballage, en particulier plastique, constitue aujourd'hui un élément indispensable de notre vie quotidienne. Son utilisation intensive dans le domaine agroalimentaire pour un usage unique à courte durée de vie incite aujourd'hui à s'orienter vers de nouveaux matériaux d'origine renouvelable et biodégradables, aux caractéristiques similaires que leurs homologues issus des ressources fossiles. Les mélanges à base de biopolymères et de biopolyesters peuvent être une bonne alternative. Dans ce présent travail de thèse, des mélanges de farine de blé, thermoplastifiée par du glycérol et de l'eau, et des polyesters biosourcés et biodégradables tels que le PLA et/ou le PHB ont été obtenus par extrusion bivis et moulés par injection thermoplastique. Les caractéristiques thermiques, thermomécaniques dynamiques, morphologiques, mécaniques et barrières de ces nouveaux matériaux ont été étudiés. De l'acide citrique a été utilisé comme agent de compatibilisant pour améliorer l'interface amidon/PLA. Les différentes investigations nous ont permis de mettre au point différents types de formulations aux caractéristiques mécaniques et barrières à la vapeur d'eau intéressantes pour la fabrication de corps de barquettes d'emballage alimentaire de denrées périssables comme la viande ou les fromages. L'aptitude au contact alimentaire des matériaux farine thermoplastifiée/polyester et l'impact de l'incorporation des polyesters sur la biodégradabilité de ces matériaux ont également été étudiés<br>From basic and essential to unnecessary and optional consumer products, packaging, particularly plastic, is today an indispensable part of our daily life. Its extensive use in the food industry for a single use and for a short shelf-life encourages us today to move towards new renewable and biodegradable materials with similar characteristics than their counterparts from fossil resources. Biopolymers and biopolyesters blends can be a good alternative. Within the framework of this present work, wheat flour, thermoplasticised by glycerol and water, and biobased and biodegradable polyesters such as PLA and/or PHB, were blended using an industrial twin screw extruder and were injection-molded into thermoplastic materials. Thermal, dynamic thermomechanical, morphological, mechanical and barriers properties of these new materials were studied. Citric acid was used as a compatibilizer to improve the interface starch/PLA. The different investigations have allowed us to develop various types of formulations, with mechanical characteristics and barrier properties to water vapor, very attractive for manufacturing plastic food packaging which can be used for meats or cheeses. Food contact suitability and biodegradability of thermoplasticised wheat flour/polyester materials have also studied
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Lempereur, Isabelle. "Bases physico-chimiques du fractionnement et de la fragmentation des grains de blé dur (Triticum durum Desf. ) par voie sèche." Montpellier 2, 1997. http://www.theses.fr/1997MON20093.
Full textAbstract:
La valeur semouliere des bles durs (triticum durum desf. ) reste souvent definie par connaissance empirique. La comprehension des bases de la fragmentation et du fractionnement du grain, et la maitrise des effets des facteurs agronomiques et genotypiques sur ces aspects etaient les objectifs de ce travail. Les facteurs intrinseques de la valeur semouliere mis en evidence sont : le rapport albumen sur enveloppes, la resistance mecanique de l'albumen amylace et l'aptitude a dissocier les parties peripheriques du grain de l'albumen amylace. La valeur semouliere est influencee par le genotype, par les traitements agronomiques (stress azote ou hydrique), et plus faiblement, par le lieu de culture et l'annee de recolte. Elle peut donc representer un objectif de selection. Le rapport albumen sur enveloppes, dont rendent compte la section et la surface du grain, s'est revele sensible au genotype et aux traitements agronomiques. A taille de grain egale, des differences significatives de comportement en mouture entre les varietes ont ete enregistrees. Plus qu'une notion de taille de grain, il semble judicieux de parler de conformation (sphericite, profondeur du sillon. . ). La mise au point d'un micromoulin permettant l'enregistrement de l'energie de broyage, a permis de suivre le comportement a la fragmentation des grains. Les indices de broyabilite prenant en compte l'energie de broyage et la reduction granulometrique sont les meilleurs predicteurs de la valeur semouliere. Cette etude a debouche sur la mise au point d'un microtest. La fractionnabilite, etudiee au niveau tissulaire et cellulaire semble etre en relation avec la teneur en composes phenoliques, et plus particulierement, en acides ferulique et diferulique. Des methodes de dosage par clhp et microspectroflurimetrie ont ete developpees. L'heterogeneite de repartition en ces composes au niveau des parois de la cellule de la couche a aleurone a ete demontree et semble liee a la plus ou moins grande aptitude au fractionnement.
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"Characterization of a putative Triticum aestivum abscisic acid receptor and its role in fungal pathogen resistance." Thesis, 2016. http://hdl.handle.net/10388/ETD-2016-01-2509.
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Abscisic acid (ABA) has been well defined as an important stress hormone in plants. The signaling pathway of ABA involves a family of pyrabactin resistant-like-1 PYR/PYL/RCAR receptors (PYL receptors) that bind ABA and form a complex with a protein phosphatase 2C (PP2C) family member resulting in downstream signaling events. The ABA receptor family has been well characterized in the model dicot Arabidopsis thaliana and more recently this characterization has branched out into cereals Oryza sativa (rice) and Hordeum vulgare (barley), as well as the monocot model plant Brachypodium distachyon and Fragaria vesca (strawberry). The analysis of these characterized ABA receptors and the use of online databases has allowed the identification of multiple putative ABA receptors in Triticum aestivum (wheat).
ABA has been historically called a positive effector. Overexpression of proteins in the ABA signalling pathway or exogenous application of ABA is known to cause an increase in drought, cold, and salt tolerance. More recently ABA has been linked to increased fungal susceptibility in several plants. The role ABA plays in the biotic stress response is still largely unexplored.
The focus of this project was to identify and characterize a putative wheat ABA receptor through bioinformatics and an in vitro enzyme activity assay, and use virus induced gene silencing (VIGS) to test what role this receptor plays in fugal susceptibility. A total of 13 putative ABA receptors were located, nine of which are unique between the wheat subgenomes. One receptor TaPYL5.1 was recombinantly expressed, purified, and confirmed as an ABA receptor through a phosphatase based enzyme activity assay. A receptor with high sequence identity to TaPYL5.1, TaPYL5.2A, was targeted for plant trials because the TaPYL5.1 plasmid sequence was codon optimized. A VIGS approach was used to knock down TaPYL5.2A in planta. The TaPYL5.2A knockdown plants were found to have an increased resistance to Fusarium Head Blight progression in the early stages of the disease.
In conclusion, wheat ABA receptors were successfully identified and an important correlation between decreased receptor levels and increased early Fusarium Head Blight resistance was found. This correlation however was not easily reproducible due to the severity of coupling VIGS with Fusarium Head Blight, and should be followed up with additional studies looking at the broader family of wheat ABA receptors.
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Wang, Weiwei. "Properties of hydroxypropylated normal wheat, waxy wheat, and waxy maize starches and an improved 1H NMR method to determine level of hydroxypropyl groups." Thesis, 2018. http://hdl.handle.net/2097/39373.
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Master of Science<br>Department of Grain Science and Industry<br>Yong Cheng Shi<br>Waxy wheat starch (WWS) containing little or no amylose has unique properties for food and industrial uses. Hydroxypropylation, a widely used means for modifying starches, could enhance functionalities of starch by substituting hydroxyl groups in starch. There are limited numbers of literatures regarding hydroxypropylation of WWS. WWS hydroxypropylated with 3.0-9.0% propylene oxide (PO) were prepared and compared to hydroxypropylated normal wheat starch (NWS) and hydroxypropylated waxy maize starch (WMS). The molar substitution (MS) of the resulting hydroxypropylated NWS, WWS and WMS was 0.055-0.151, 0.048-0.133, and 0.049-0.139, respectively. Gelatinization temperatures and enthalpy of hydroxypropylated starches were significantly lower than those of their unmodified counterparts and the extent of decrease was positively correlated to the MS. Differential scanning colorimetry (DSC) results showed that hydroxypropylation reduced the retrogradation of the starches during the storage after gelatinization but there were differences between the starches. For the same level of PO reaction (3 and 5% PO), hydroxypropylated WWS retrogradated less than hydroxypropylated WMS, suggesting that for the same level of cold storage stability, less PO is needed for WWS. After reacted with 6% PO, MS was 0.092 and 0.094, respectively, for WWS and WMS, and no retrogradation was observed for those hydroxypropylated starches, indicating that at MS ~0.094, hydroxypropyl groups prevents amylopectin chains from re-associating and forming crystalline structures. In contrast, a higher level of PO (9%) was needed to react with NWS to achieve the hydroxypropylated starch with an MS of 0.151 that gave no retrogradation. Consistent with microscopic observation results, Micro-Visco-Amylograph (MVA) analysis showed hydroxypropylated starches developed viscosity at lower temperatures and had improved hot and cold viscosities.
The specific characteristics of hydroxypropylated starches are related to the degree of hydroxypropylation. Therefore, it is critical to determine the level of hydroxypropylation in modified starches. 1H NMR is a simple and rapid means of determining hydroxypropyl (HP) group in modified starches. In this study, a method to prepare a HP starch for NMR analysis was improved. The optimum parameters proposed to hydrolyze HP starches were 10% starch solid content, 3.5% (wt.%) DCl in D2O as the solvent, sodium acetate as an internal standard, heating at 90oC for 1 h. Optionally, 6% (v/v) trifluoroacetic acid-d as the water-peak shifting reagent. Six hydroxypropylated starch samples and two commercial cross-linked and hydroxypropylated starch samples were hydrolyzed with this modified method before 1H NMR analysis, and the results of HP group content in the samples were in agreement with the results from an enzyme-catalyzed method, which indicate that the improved acid hydrolysis method is applicable for both hydroxypropylated starch and cross-linked and hydroxypropylated starch.
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Dupuis, Brigitte G. "Characterization of acetic acid soluble and insoluble fractions of glutenin of bread wheat." 1995. http://hdl.handle.net/1993/17629.
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Li-hua, You, and 游麗華. "Partition of Phenolic Compounds in Reverse Micelles and Kinetic Properties of Wheat Germ Acid Phosphatase." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/75480209930521112593.
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碩士<br>國防醫學院<br>生物化學研究所<br>86<br>Reverse micelles are aggregates of surfactant molecules containing an inner core of water molecules, dispersed in a continuous organic solvent medium. These system are optically transparent and thermodynamically stable. The considerable biotechnological potential of these system is derived principally from the ability of water droplets to dissolve enzymes, in much the same way as does bulk water. In AOT-isooctane reverse micelles system phenolic compounds were observed to have partition phenomenon. At low water contents, some of the phenolic compounds located in the vicinity of the interface interact with the polar heads of the surfactant; these interaction can be quite strong and specific. As water is added or pH values is increasing, the changes in phenolic compounds binding at the polar regions of the micelles, together with the evolution of the interfacial region and of the cosolubilized water structure account for the change in reactivity of the medium. We have studies the partition of phenolic compounds in CTAB reverse micelles. Absorption spectra of the phenolic compounds was measured in CTAB-isooctane reverse micelles and were used in estimation of the partition of phenolic compounds between water pool and interface region of the system. p-Nitrophenol in different surfactant -isooctane reverse micelles has different Kd values. The effect of solubilized water on the spectral charateristic can be interpreted in terms of increased polarity of the probe microenvironment.The enzyme activity in the CTAB-isooctane reverse milcelles is lower than in water solution.The experimental data are consistent with an interface reorganization in the micellar domain with a concomitant water penetration along the surfactant head group to interface.
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Schoeman, Carien J. "Phenolic acid composition and antioxidant properties of aqueous extracts from wheat and sorghum flours and cookies." Diss., 2014. http://hdl.handle.net/2263/43235.
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Cereal grains are important food staples and sources of antioxidant phenolics. Dietary phenolics have the potential to reduce oxidative stress and help combat associated conditions like cardiovascular disease. The availability of phenolics from sorghum and wheat products (e.g. cookies) for absorption depends on their fate during processing and during digestion in the gastro-intestinal tract.
The effect of simulated GIT pH conditions on total phenolic content (TPC), phenolic acids and antioxidant properties of whole wheat, non-tannin sorghum and condensed tannin sorghum flours and their cookies was determined. The TPC (Folin-Ciocalteu method) of all the samples analysed ranged between 37.0 – 405.3 mg Catechin equivalent / 100 g sample. Extracts from cookies had higher overall TPC than from flours, possibly due to release of bound phenolics or formation of Maillard reaction products (with reducing properties) during baking. Extracts from condensed tannin sorghum samples had higher TPC than the other cereal extracts, possibly due to presence of tannins in the tannin sorghum samples. Phenolic acids were analyzed using High Performance Liquid Chromatography-Mass Spectrometry. p-Hydroxybenzoic, caffeic, p-coumaric and ferulic acids were identified in extracts from the flour and cookie samples. Ferulic acid was the dominant phenolic acid in both wheat and sorghum samples ranging between 109.8 – 1389.4 mg / 100 g sample.
ABTS radical scavenging capacity of all the extracts analysed ranged between 0.1 – 4.7 mM Trolox equivalent/ 100 g sample. Condensed tannin sorghum sample extracts had the highest ABTS radical scavenging capacity, possibly due to tannins in the extracts. Metal chelation capacity of all the extracts analysed (ferrous ion chelation assay) ranged between 325.6 – 8424.9 μg EDTA equivalent/ g sample. Wheat sample extracts had the highest metal chelating capacity. Inhibition of copper-mediated LDL oxidation (thiobarbituric acid reactive substances assay) of all the samples analysed ranged between 1.0 – 5.4 μM Trolox equivalent / g sample, with wheat extracts having the highest inhibition. Inhibition of LDL oxidation by the extracts (especially from wheat) may be related to their metal chelation ability as shown by high and positive correlation (r = 0.86) between inhibition of LDL oxidation and Iron Chelating effect (%).
There were positive overall correlations between TPC and antioxidant properties (radical scavenging or metal chelation). Antioxidant properties of the extracts may be related to their phenolic contents. Phenolic acids identified in the extracts such as ferulic and caffeic acids may exert antioxidant effects by radical scavenging or metal chelation.
The presence of phenolic acids in the GIT pH extracts of the wheat and sorghum cookies shows that they are stable under GIT pH conditions. Overall, this study shows that the cookies have potential as a health promoting ready-to-eat snack to protect against diseases related to oxidative stress such as atherosclerosis.<br>Dissertation (MSc)--University of Pretoria, 2014.<br>lk2014<br>Food Science<br>MSc<br>Unrestricted
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Alves, João Tiago Roque. "Effectiveness of Ascorbic Acid and Zinc as drought antagonists in bread wheat plants monitored by different DNA markers." Master's thesis, 2018. http://hdl.handle.net/10348/8821.
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O trigo mole é um cereal economicamente importante a nível mundial e devido às alterações climáticas, a seca é frequente afetando o rendimento e a qualidade desta cultura. O Ácido Ascórbico (AsA) e o Zinco (Zn) podem atuar como antagonistas da seca minimizando os efeitos negativos deste stresse abiótico. A seca e outros stresses abióticos geram instabilidade genómica nas plantas que pode ser monitorizada por marcadores moleculares. “Conserved DNA Domain Polymorphism” (CDDP) e “Start Codon Targeted” (SCoT) são “gene-targeted” markers capazes de detetar variação em regiões genómicas funcionais; marcadores baseados em retrotransposões (RTNs) podem monitorizar a atividade dos RTNs e os marcadores “Random Amplified Polymorphic DNA” (RAPD) podem detetar instabilidade genómica ao longo do genoma. Neste trabalho, pretendeu-se testar a eficiência de “priming” de sementes e/ou a aplicação foliar com AsA ou sulfato de Zn heptahidratado (ZnSO4.7H2O) para mitigação da seca em plantas de trigo mole da cv. Jordão através da avaliação da instabilidade genómica em plantas tratadas relativamente às plantas controlo ambas em dois regimes hídricos (rega e seca) usando marcadores CDDP, SCoT, “Inter-Retrotransposon Amplified Polymorphism” (IRAP), “Retrotransposon-Microsatellite Amplified Polymorphism” (REMAP), “interPriming Binding Site” (iPBS), “Inter-Simple Sequence Repeat” (ISSR) e RAPDs. A instabilidade genómica foi refletida pelo aparecimento de novas bandas e pela perda de bandas nas plantas tratadas relativamente às plantas controlo. Assim, com base nas percentagens de polimorfismo obtidas com os diferentes marcadores de DNA em todos os tratamentos e em ambos os regimes hídricos, extrapolou-se o antagonista da seca mais adequado ao trigo mole. Os polimorfismos gerados poderão ter sido devidos a alterações na sequência do DNA quer dos locais de hibridação dos primers quer na região genómica entre eles. Ambos os marcadores “gene-targeted”, SCoT e CDDP permitiram uma análise da variação do DNA ao longo do genoma e foram adequados à deteção de instabilidade genómica em plantas de trigo mole em stresse abiótico. Contudo, consideraram-se osresultados CDDP mais fiáveis uma vez que foram produzidos com base em primers especifícos para genes de resposta ao stresse hídrico previamente isolados em trigo mole. As técnicas IRAP e REMAP evidenciaram as taxas de polimorfismo mais elevadas, corroborando a elevada actividade insercional e transcripcional dos RTNs em plantas sob stresse abiótico como a seca, a qual pode ser detetada por marcadores baseados em RTNs. Os marcadores RAPD demonstraram ser úteis para uma análise genómica relatiavmente à deteção de instabilidade genómica em plantas de trigo mole sob stresse abiótico. Em suma, integrando todos os dados moleculares e estatísticos obtidos neste trabalho, o “priming” de sementes com Zn (Zn priming) parece ser o tratamento mais adequado para plantas de trigo mole sob seca.<br>Bread wheat is economical important worldwide and due to the climate changes drought is frequent and it is affecting the yield and quality of this crop. Ascorbic Acid (AsA) and Zinc (Zn) can act as drought antagonists minimizing the negative effects of this abiotic stress. Drought and other abiotic stresses generate genomic instability in plants that can be monitored by molecular markers. Conserved DNA Domain Polymorphism (CDDP) and Start Codon Targeted (SCoT) are gene-targeted markers that are able to assess variation in functional genomic regions; retrotransposons (RTNs)-based markers may moniter the RTNs activity and Random Amplified Polymorphic DNA (RAPD) are able to screen genomic instabilities throughout the genome. In this study, we intend to test the effectiveness of seed priming and/or foliar application with Ascorbic Acid (AsA) or Zinc sulphate heptahydrate (ZnSO4.7H2O) for drought mitigation in bread wheat plants of cv. „Jordão‟ by evaluating the genomic instability in treated plants relative to control plants both under two water regimes (watering and drought) using CDDPs, SCoTs, Inter-Retrotransposon Amplified Polymorphism (IRAP), Retrotransposon-Microsatellite Amplified Polymorphism (REMAP), inter-Priming Binding Site (iPBS), Inter-Simple Sequence Repeats (ISSRs) and RAPDs. The genomic instability was reflected by the appearance of new bands and loss of bands in treated plants relative to control. Therefore, based on the percentage of these polymorphic bands achieved with the different DNA markers in all treatments of both water regimes, it was extrapolated the most suited drought antagonist for bread wheat. The polymorphisms were generated due to alterations in the DNA sequence that may affect both priming binding sites and the genomic region between them. Both SCoT and CDDP gene-targeted markers allowed a genome-wide DNA variation analysis being suitable for detection of genomic instability in bread wheat plants under abiotic stress. However, we considered more reliable the CDDP results since their production was based on primers specific to water stress responsive genes previously isolated in bread wheat. The IRAP and REMAP techniques evidenced higher percentages of polymorphism, corroborating the assumption that plants under abiotic stress such as drought have higher RTNs insertional and transcriptional activities that could be detectable by RTNs-based markers. RAPD assays demonstrated to be a useful tool in order to do a genome wide analysis for the detection of genomic instabilities in bread wheat plants under abiotic stress. Overall, integrating all the molecular and statistical results achieved in this work, seed priming with Zn (Zn priming) appeared to be the most suitable treatment for bread wheat plants under drought.
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Kim, Hee Sun. "Determination of erythroascorbic acid in baker's yeast and the effect of D-erythroascorbic acid on flow-properties of wheat flour dough." 1988. http://hdl.handle.net/2097/22532.
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Wang, Jun Chao, and 王俊超. "Influence of two kinds of humic acid on the bioavailability of zinc and cadmium to soybean and wheat plants." Thesis, 1995. http://ndltd.ncl.edu.tw/handle/63343504204263541197.
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Chen, Ai-Hwa, and 陳僾華. "Lactic Acid Bacteria ,Black Wheat Juice and Fruit Vegetable Fermentant on SD Rat Intestinal Microflora and Serum Antioxidant Enzyme Activity." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/29225446005828730020.
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碩士<br>實踐大學<br>食品營養與保健生技學系碩士班<br>99<br>This study was divided into two parts: The aim of first part study,was evaluate the effect of lactic acid bacteria and/or fruits vegetable fermentant in rat intestinal microflora and serum antioxidant capacity.Sixty Sprague-Dawley rats were randomly divided into six groups : control group, group A (lactic acid bacteria 3.60 × 107 CFU), group B (lactic acid bacteria 3.60 × 108 CFU), group C (lactic acid bacteria 7.20 × 108 CFU), group D (lactic acid bacteria 3.60 × 107 CFU, fruits and vegetables hydrolyzate 178mg/kg/day), group E (fruits and vegetables hydrolysates 178mg/kg/day), fecal samples were collected at weeks 4 and 8 for intestinal microflora determination.The serum Catalase, SOD, GSH, GPX were examinated for antioxidant capacity.The results showed that total anaerobes, bifidobacteria, lactobacilli counts increased in group A, B, C, D and E when compared with control group at the 4 week period and 8 week period in the fecal and cecum.The E.coli and Clostridium perfringens counts decreased in group A, B, C, D and E when compard with control group at the 4 week period and 8 week period in the fecal and cecum. The Catalase, SOD, GSH antioxidant capacity increased in group A, B, C, D and E when compared with the control group. GPX antioxidant capacity increased in group B, C, D and E when compared with control group. The aim of second part study, was to evaluate the effect of black wheat juice extract on rat intestinal microflora. Fifty Sprague-Dawley rats were randomly divided into five groups : control group, group A (4.12 g/kg bw /day), group B (8.23 g/kg bw /day), group C (16.26 g/ kg bw/day) and group D (41.16 g/ kg bw/day).Fecal samples were collected at weeks 2, 4 and 8 for intestinal microflora determination.The results showed that total anaerobes, bifidobacteria, lactobacilli counts increased in group A, B, C and D when compared with control group at the 2 week period, 4 week period and 8 week period in the fecal and cecum.The E.coli counts decreased in group B, C and D when compared with control group at 2 week period on the fecal, the E.coli amd Clostridium perfringens counts decreased in group A, B, C and D when compared with control group at the 4 week period and 8 week period. Therefore, lactic acid bacteria and/or fruits vegetable fermentant can increase the serum antioxidant capacity and improve the intestinal microflora.Black wheat juice also can improve the intestinal microflora.Lactic acid bacteria, fruits vegetable fermentant and black wheat juice can improve the intestinal microflora through to maintain normal bowel function.
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Ambardekar, Amogh. "Modifications in visco-elasticity of gluten diacteyl tartaric acid ester of monoglyceride (DATEM), ascorbic acid, urea and dithiothreitol and its effects on mixing and baking properties in commercial wheat flours." 2009. http://digital.library.okstate.edu/etd/Ambardekar_okstate_0664D_10538.pdf.
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Chang, Yu-Hsuan, та 張鈺瑄. "Methoxy Poly(ethylene glycol)-Poly(ε-caprolactone) Nanoparticles Grafted with Wheat Germ Agglutinin and Folic Acid for Targeting Delivery of Anti-cancer Drug to Human Glioblastoma Cells". Thesis, 2013. http://ndltd.ncl.edu.tw/handle/60120632932394780573.
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碩士<br>國立中正大學<br>化學工程研究所<br>101<br>A dual-targeting drug carrier methoxy poly(ethylene glycol)-poly(ε-caprolactone) nanoparticles (MPEG-PCL NPs) and surface modified with wheat germ agglutinin (WGA) and folic acid (FA) for enhanced anticancer drug delivery across the blood–brain barrier (BBB) and targeting to U87MG cells. The MPEG-PCL NPs was prepared using emulsion-solvent evaporation techniques in presence of Pluronic F127. Furthermore, the cell co-culture model was established by consisting of human brain-microvascular endothelial cells, human astrocytes and human brain vascular pericytes to investigate various formulations of drug-loaded NPs permeability of the in vitro BBB model and dual-targeting effect for U87MG cells, then observing the cellular uptake of human brain-microvascular endothelial cells and U87MG cells by immunofluorescence. The results indicated that increase in concentration of F127 from 0.25% to 1% made significant decrease in the average diameter and 1% w/v of F127 was considered as optimum for the preparation of nanoparticles, the optimum average diameter was about 150 nm. In addition, copolymers with shorter PCL blocks formed smaller particles size and encapsulated less drug molecules, but released faster. The results of the release showed that the NPs in this study were pH-dependent. Transepithelial electrical resistance (TEER) value of the in vitro BBB model was 310 ± 11.7 Ω × cm2 and the order of transport across the BBB was FWNPs > WNPs > FNPs > NPs, the dual-targeting nanoparticles FWNPs was 1.5- to 2.1-fold higher than non-modified NPs and the result of dual-targeting effect indicated that FWNPs were significantly against U87MG cells after cross the BBB. Finally, the results of immunofluorescence demonstrated that FWNPs increased intracellular in HBMECs and U87MG cells. Therefore, it may be concluded that FWNPs has the potential to be applied as a targeted delivery for anticancer drug in the treatment of brain cancer.