Dissertations / Theses on the topic 'Chemical Preservation'

The treatability of six Malaysian timbers namely Red Balau (Shorea guiso), Kapur (Dryobafanops aromatica), Kasai (Pometia pinnata), Kulim (Scorodocarpus borneensis), Kempas (Koompassia malaccensis) and Keruing (Dipterocarpus grandiflorus) using the applied pressure processes (oscillating pressure, conventional Bethell and a modified Bethell process) was investigated. Treatments were carried out with a commercial water-borne copper-chromearsenic (CCA) preservative, known as Celcure-AP. The conventional Bethell process was the most effective method of wood treatment followed by the modified Bethell and the oscillating pressure process. While sufficient preservative retention and absorption was achieved in Kempas and Keruing to meet the Malaysian Standard MS 386 : 1986 specifications for exterior timber used in ground contact, the other four timbers - Red Balau, Kapur, Kasai and Kulim did not fulfil this requirement, even when treated at the most extreme treatment conditions. Using the three pressure processes, seasoning period and treatment time were found to have significant effects on preservative retention and penetration in all timber species. Investigations into the effect of three pretreatment procedures - steaming, incising and ponding to improve the treatability of the six timber species were carried out. Incising was the most effective pretreatment procedure in enhancing the treatability of these timbers. However, at the highest incising density employed (4,500 incisions/m2), it was still not possible to treat Red Balau, Kapur, Kasai and Kulim timber to achieve satisfactory target preservative retention and penetration. The less effective incising procedure was due mainly to the low incising density used. The possibility of improving the treatability of these four timber species further using higher incising densities and other methods of inCising pretreatment is discussed. Steaming, incising and ponding pretreatments had a pronounced effect on the strength properties of timbers based on reduction of their modulus of elasticity (M.D. E.), modulus of rupture (M.O.A.), compressive strength and hardness. The highest strength losses were observed in timbers that had been ponded for 6 months. Significant strength losses were also observed in incised and steamed timbers, but the magnitudes were lower than the 6 month ponding regime. This was attributed to low incising density and the short steaming period. The performance of Celcure-AP in the six timber species was evaluated in laboratory and field tests. In addition, a copper-azole formulation (Tanalith-3485) was also evaluated on Kempas timber. Laboratory tests involved exposure of treated wood blocks to five decay fungi - Pycnoporus sanguineus, Trametes versicolor, Coniophora puteana, Gloeophyllum trabeum and Oligoporus placenta. The less durable timbers - Kempas and Keruing needed a higher loading of Celcure-AP in order to give equal performance compared to the more durable timbers - Red Balau, Kapur, Kasai and Kulim. Based on copper retention in treated samples, a higher loading of Tanalith-3485 was required in Kempas to achieve comparable results to Celcure-AP treated samples. However, the concentration levels of Tanalith-3485 used in the present study were sufficient to afford protection to Kempas stakes exposed for 36 months in the field test. A longer exposure period is however, recommended for a full evaluation of timber/preservative combinations against wood deteriorating organisms under Malaysian conditions. In the field test, soft rot fungi were the main causal organisms in the attack of timbers in test site A (fungal test bed), while in test site B stake failure was due mainly to termite attack.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 2007.
Includes bibliographical references (leaves 142-149).
Inspired by the variety of organisms that are naturally desiccation tolerant, anhydrobiotic preservation potentially furnishes a means of processing and storing mammalian cells in a state of "suspended animation" at ambient conditions in carbohydrate glasses. Although there have been promising applications of this technique, especially when employing the disaccharide trehalose, the ultimate goal of room temperature long-term storage has thus far not been achieved -- at least in part owing to an incomplete understanding of the fundamental cellular damage mechanisms. Although there have been many studies examining the thermodynamics of relevance to anhydrobiotic preservation, particularly with regard to lipid phase and the effect of carbohydrates thereupon, comparatively little attention has been paid to the effect of transport kinetics on preservation success. Further, although cells are typically dried in carbohydrate solutions on a solid support, there are few studies on the role played by the support. This work seeks to help remedy such deficiencies. First, considering damage mechanisms at the individual cell level, giant liposomes were employed as a model cell system, given that the cell membrane is a key damage site.
(cont.) The influence of solid surface - lipid bilayer interactions was investigated in the presence and absence of trehalose. Two lipids were chosen in order to determine the effect of lipid phase on surface interactions: gel-phase 1,2-distearoyl-sn -glycero-3-phosphocholine (DSPC) and liquid-crystalline phase 1,2-dilauroyl-sn-glycero-3-phosphocholine (DLPC). In the absence of trehalose, DSPC liposomes adsorbed to the polystyrene support surface, producing irreversible structural changes and apparent leakage of all intravesicular solute upon drying and re-hydration. Addition of trehalose significantly reduced vesicle adsorption with only transitory intravesicular solute leakage for the re-hydrated vesicles, likely owing to a transient osmotic imbalance; however, at very low moisture contents, the vesicles underwent permanent structural changes. In contrast to the results with DSPC vesicles, DLPC vesicles largely evaded adsorption and exhibited high intravesicular solute retention when dried and re-hydrated even in the absence of trehalose, despite significant internal structural changes. Next, taking a more macroscopic view, the influence of the solid support and desiccation kinetics was analyzed at the whole droplet level.
(cont.) During desiccation, sessile droplets of glass-forming carbohydrate solutions exhibit complex dynamic phenomena, including fluid flow, droplet deformation and crack formation, all of which may alter cell preservation efficacy. Two factors were identified that strongly influenced the features of the preserved giant liposome suspension droplets: the underlying surface and the liposome concentration. In particular, the surface altered the droplet shape as well as the microflow pattern - and in turn the moisture conditions encountered by the liposomesr during desiccation. A ring deposit formed when the droplets were dried on polystyrene -- as would be expected owing to the capillary flow that generally occurs in pinned droplets. In contrast, when dried on the more hydrophilic glass slide, the resulting droplets were thinner and the liposomes accumulated near their centers -- an unexpected result likely owing to the glass-forming nature of the trehalose solutions. As might be anticipated given the variations in liposome distribution, the choice of surface also influenced crack formation upon continued drying. In addition to providing a preferential path for drying, such cracks are relevant because they could inflict mechanical damage on cells.
(cont.) Liposome concentration had an even more profound effect on crack formation; indeed, while cracks were found in all droplets containing liposomes, in their absence few of the droplets cracked at all, regardless of the surface type. Given the experimentally-determined non-uniform distribution of liposomes within the sessile droplets, a finite element method model was formulated to assess the moisture content variation within desiccating trehalose solution microdroplets - both unsupported and sessile. In the unsupported droplet, a thin glassy skin was found to form at the droplet surface, which significantly hampered further evaporation owing to the extremely low diffusivity of water in trehalose glasses. Thus, residual water was essentially trapped in the droplet core for long times, preventing a transition to the glassy state there. This is significant for anhydrobiotic preservation because most liposomes, or cells, would be located in the droplet core rather than in the thin glassy skin. The sessile droplet provided another degree of complexity in that the moisture concentration was inhomogeneous not only in the direction perpendicular to the interface, but along it as well, since the glassy skin did not form uniformly, instead progressing inward from the contact line.
(cont.) In summary, surface interactions were found to play a significant role in anhydrobiotic preservation, both at the cellular level through adsorption and at the whole droplet level through their effect on distribution of suspended liposomes (or cells) and crack formation. Further, kinetic phenomena had a strong influence, again at the cellular level through transient osmotic imbalances and at the whole droplet level in the form of inhomogeneous moisture distributions. Such effects clearly merit further investigation in the development of anhydrobiotic preservation protocols.
by Dana R. Adams.
Ph.D.

As foodstuffs are being produced, transported and stored in greater quantities than ever before in human history and with an alarming amount of food products being lost to spoilage every year, new, environmentally friendly ways of preserving food products are being actively researched and developed in today’s world. Oxygen is a key pathway towards food decay and destruction, due to its dual roles as a source of respiration for the multitude of microorganisms that can cause food spoilage and through direct destruction through oxidation reactions within food products that cause oxidative deterioration. Fuel cells have the theoretical potential to be an energy efficient and environmentally friendly way of preserving food, such as fish, fruit and vegetables.  Because of their nature to consume oxygen through the electrochemical reactions that produces their electrical power, they have the potential to be used to reduce localised oxygen content for the storage and transportation of foods, minimising their spoilage, as well as potentially providing electrical energy for other components in potential control systems for the fuel cell. The purpose of this project is to design and build a PEM fuel cell and examine its potential for lowering of oxygen concentrations at the gas output at the cathode.  The outcome of these experiments are designed to validate the  theoretical capacity of fuel cells to reduce output oxygen concentrations to levels that are able to aid in the preservation of foodstuffs.  It is hoped that this study, in conjunction with the researched literature, can be used as a guide for future food shipping and storage methods. The experimental stage of this diploma work was unsatisfactory. The fuel cell was unable to produce a voltage and the reactant gases were unable to flow through the fuel cell due to a design flaw. Therefore the effectiveness of a fuel cell for depletion of oxygen to levels able to preserve food is based on the theoretical basis of the internal PEM fuel cell reactions, as well as studying past literature and patents. If the theoretical ability of the fuel cell is proven, it can be asserted that PEM fuel cells have the potential to be a real contender in the field of food preservation in shipping and storage, as well as offering greater levels of control for supplies for how and when they can ship their product. However this will require more independent research development work on the effects of low oxygen concentrations on a fuel cell operation as well as the preservation effects on a greater variety of foodstuffs. Furthermore, more research is required for more efficient and cheaper fuel cell catalysts or innovative designs are required to avoid concentration losses that arise from oxygen reduction at low oxygen levels.

Thesis (Ph.D.)--Joint Program in Oceanography (Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences and the Woods Hole Oceanographic Institution), 2000.
Vita.
Includes bibliographical references (leaves 266-286).
Phosphorus, an essential nutrient, is removed from the oceans only through burial with marine sediments. Organic phosphorus (Prog) constitutes an important fraction (ca. 25%) of total-P in marine sediments. However, given the inherent lability of primary Prog biochemicals, it is a puzzle that any Porg is preserved in marine sediments. The goal of this thesis was to address this apparent paradox by linking bulk and molecular-level Porg information. A newly-developed sequential extraction method, which isolates sedimentary Pol reservoirs based on solubility, was used in concert with Prog nuclear magnetic resonance spectroscopy (31P-NMR) to quantify Prog functional group concentrations. The coupled extraction/ 31P-NMR method was applied to three sediment cores from the Santa Barbara Basin, and the first-ever high-resolution depth profiles of molecular-level Porg distribution during diagenesis were generated. These depth profiles were used to consider regulation of Prog distribution by biomass abundance, chemical structure, and physical protection mechanisms. Biomass cannot account for more than a few percent of sedimentary Prog. No evidence for direct structural control on remineralization of Porg was found. Instead, sorptive protection appears to be an important mechanism for Prog preservation, and structure may act as a secondary control due to preferential sorption of specific Porg compound classes.
by Kirsten Lynn Laarkamp.
Ph.D.

This work discusses optimisation of the cryopreservation of Bacillus licheniformis cell banks, used as inoculum for α-amylase producing 5 L batch fermentations. The effect of the presence of various cryopreservants including glycerol, Tween 80 and dimethyl sulphoxide on final fermentation performance measured by biomass and α-amylase concentration was investigated using optical density, dry cell weight, colony forming units, and multi-parameter flow cytometry. The application of multi-parameter flow cytometry using the fluorophores DiBac\(_4\)(3) and PI allowed real time viability measurements of individual microbial cells to be monitored before and after cryopreservation and during the fermentation process; viability here being defined as a cell having an intact and fully polarised cytoplasmic membrane. It was found that the concentration and type of cryopreservant used had a significant effect on microbial cell physiology and population heterogeneity during resuscitation recovery immediately after thawing. Cell banks prepared with Tween 80 were fastest to recover after freezing in comparison to cell banks prepared with dimethyl sulphoxide which showed the slowest growth rates. Interestingly cells preserved in glycerol recovered at a similar rate to cells frozen without cryopreservant. Despite different responses to the freezing process when each cell bank was used as inoculum for 5 L batch fermentations very little difference was noticed in overall process performance with respect to α-amylase production, growth rate and final biomass concentration.

Freshwater wetland soils of the Everglades were studied in order to assess present environmental conditions and paleo-environmental changes using organic geochemistry techniques. Organic matter in dominant vegetation, peat and marl soils was characterized by geochemical means. Samples were selected along nutrient and hydrology gradients with the objective to determine the historical sources of organic matter as well as the extent of its preservation. Effective molecular proxies were developed to differentiate the relative input of organic matter from different biological sources to wetland soils. Thus historical vegetation shifts and hydroperiods were reconstructed using those proxies. The data show good correlations with historical water management practices starting at the turn of the century and during the mid 1900’s. Overall, significant shortening of hydroperiods during this period was observed. The soil organic matter (SOM) preservation was assessed through elemental analysis and molecular characterizations of bulk 13C stable isotopes, solid state 13C NMR spectroscopy, UV-Vis spectroscopy, and tetramethyl ammonium hydroxide (TMAH) thermochemolysis-GC/MS. The relationship of the environmental conditions and degradation status of the soil organic matter (SOM) among the sites suggested that both high nutrient levels and long hydroperiod favor organic matter degradation in the soils. This is probably the result of an increase in the microbial activity in the soils which have higher nutrient levels, while longer hydroperiods may enhance physical/chemical degradation processes. The most significant transformations of biomass litter in this environment are controlled by very early physical/chemical processes and once the OM is incorporated into surface soils, the diagenetic change, even over extended periods of time is comparatively minimal, and SOM is relatively well preserved regardless of hydroperiod or nutrient levels. SOM accumulated in peat soils is more prone to continued degradation than the SOM in the marl soils. The latter is presumably stabilized early on through direct air exposure (oxidation) and thus, it is more refractory to further diagenetic transformations such as humification and aromatization reactions.

Freshwater wetland soils of the Everglades were studied in order to assess present environmental conditions and paleo-environmental changes using organic geochemistry techniques. Organic matter in dominant vegetation, peat and marl soils was characterized by geochemical means. Samples were selected along nutrient and hydrology gradients with the objective to determine the historical sources of organic matter as well as the extent of its preservation. Effective molecular proxies were developed to differentiate the relative input of organic matter from different biological sources to wetland soils. Thus historical vegetation shifts and hydroperiods were reconstructed using those proxies. The data show good correlations with historical water management practices starting at the turn of the century and during the mid 1900’s. Overall, significant shortening of hydroperiods during this period was observed. The soil organic matter (SOM) preservation was assessed through elemental analysis and molecular characterizations of bulk 13C stable isotopes, solid state 13C NMR spectroscopy, UV-Vis spectroscopy, and tetramethyl ammonium hydroxide (TMAH) thermochemolysis-GC/MS. The relationship of the environmental conditions and degradation status of the soil organic matter (SOM) among the sites suggested that both high nutrient levels and long hydroperiod favor organic matter degradation in the soils. This is probably the result of an increase in the microbial activity in the soils which have higher nutrient levels, while longer hydroperiods may enhance physical/chemical degradation processes. The most significant transformations of biomass litter in this environment are controlled by very early physical/chemical processes and once the OM is incorporated into surface soils, the diagenetic change, even over extended periods of time is comparatively minimal, and SOM is relatively well preserved regardless of hydroperiod or nutrient levels. SOM accumulated in peat soils is more prone to continued degradation than the SOM in the marl soils. The latter is presumably stabilized early on through direct air exposure (oxidation) and thus, it is more refractory to further diagenetic transformations such as humification and aromatization reactions.

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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Thesis (Ph. D.)--Ohio State University, 2004.
Document formatted into pages; contains xiv, 143 p. Includes bibliographical references. Abstract available online via OhioLINK's ETD Center; full text release delayed at author's request until 2005 June 21.

Two experiments were conducted with caged layer waste. In the first experiment fresh waste was treated with: no additive, 2% formaldehyde, 3% sodium metabisulfite, 1% formaldehyde and 2% propionic acid, 3% formic and 2% propionic acids and stored in polyethylene lined 208 liter metal drums. In experiment II waste treated with 2% formaldehyde, 1 % formaldehyde and 2% prop ionic, 3 % formic and 2% propionic (w/w), stored for at least 42 d, used in a metabolism trial as N supplements to a basal diet fed to sheep. The formaldehyde, formaldehyde/propionic and formic/propionic treatments eliminated the bacterial decomposition of the waste and no undesirable fermentation was observed on the stored material. Waste treated with no additive or sodium metabisulfite underwent putrefaction. Nitrogen supplementation of a basal diet with treated caged layer wastes improved apparent digestibility of crude protein and N retention in sheep fed these diets. Supplementation of a basal diet with chemically treated caged layer waste improves the nutritional value of the diet which suggests that caged layer waste is efficiently utilized as a N source by ruminants when used as a protein supplement.
Master of Science

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Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

Proteins—polymers of amino acids—are a major class of biomolecules whose myriad functions facilitate many crucial biological processes. Accordingly, human control over these biological processes depends upon the ability to study, produce, and modify proteins. One innovative tool for accomplishing these aims is cell-free protein synthesis (CFPS). This technique, rather than using living cells to make protein, simply extracts the cells' natural protein-making machinery and then uses it to produce protein in vitro. Because living cells are no longer involved, scientists can freely adapt the protein production environment in ways not otherwise possible. However, improved versatility and yield of CFPS protein production is still the subject of considerable research. This work focuses on two ideas for furthering that research.The first idea is the adaptation of CFPS to make proteins containing unnatural amino acids. Unnatural amino acids are not found in natural biological proteins; they are synthesized artificially to possess useful properties which are then conferred upon any protein made with them. However, current methods for incorporating unnatural amino acids do not allow incorporation of more than one type of unnatural amino acid into a single protein. This work helps lay the groundwork for the incorporation of different unnatural amino acid types into proteins. It does this by using modified aminoacyl-tRNA synthetases (aaRSs), which are key components in CFPS, to be compatible with unnatural amino acids. The second idea is the preservation of DNA templates from enzyme degradation in CFPS. Among the advantages of CFPS is the option of using linear expression templates (LETs) in place of plasmids as the DNA template for protein production. Because LETs can be produced more quickly than plasmids can, using LETs greatly reduces the time required to obtain a DNA template for protein production. This renders CFPS a better candidate for high-throughput testing of proteins. However, LETs are more susceptible to enzyme-mediated degradation than plasmids are, which means that LET-based CFPS protein yields are lower than plasmid-based CFPS yields. This work explores the possibility of increasing the protein yield of LET-based CFPS by addition of sacrificial DNA, DNA which is not used as a protein-making template but which is degraded by the enzymes in place of the LETs.

Doutoramento em Química
During the last years, the use of high hydrostatic pressure (HHP) as a non-thermal technology for preservation or aging of wine has increased substantially in the academic community. However, HHP treated wine has been only analysed after the pressure treatment, with no knowledge available on the effects of HHP during subsequent storage. The results presented in this thesis showed that HHP treatments influence the chemical and sensorial properties of wine during storage. The application of high hydrostatic pressure treatments in winemaking for wine preservation, as an alternative to sulphur dioxide, was evaluated studying the effect of HHP in the physicochemical and sensorial properties of red and white wines during bottle storage. High pressure treatments with 5 min of processing time and pressures of 425 and 500 MPa were shown to influence on both red and white wine physicochemical and sensorial characteristics. However, the effects were only perceptible after, at least, 6 months of storage. The alterations that occurred on the pressurized red wine characteristics, such as the more orange-red colour and the lower antioxidant activity (15-27% less), total phenolic content (9% less), and anthocyanins content (45–61% less), were due to an increase of condensation reactions of phenolic compounds. The increase of these condensation reactions lead to the formation of compounds with higher degree of polymerisation that became insoluble along storage, increasing consequently the amount of wine deposits in the pressurized wines. In terms of white wines, pressurized wines showed, after one year of storage, a more brownish colour and a lower antioxidant activity (15% less) and total content of phenolic compounds (10% less) when compared to the unpressurized wines. These results, together with the lower content of free amino acids (15-20% less) and higher content of furans (up to 70% more), present in the pressurized wines after nine months of storage, led to propose an effect of HHP treatments in the acceleration of Maillard reactions that occur during the wine storage period. Therefore, contrary to the pressurized sulphur dioxide-free red wine, the pressurized white wines were not considered suitable for commercialization as table wines due to the higher brownish colour and cooked fruit aroma, characteristics of an aged or thermally treated wine.Additionally, the impact of the pressure treatments on the volatile composition of sulphur dioxide-free red and white wines, during bottle storage, was evaluated. More than 160 volatile compounds, distributed by 12 chemical groups, were identified in both wines. At the end of storage, the pressurized wines presented a higher content of furans, aldehydes, ketones, and acetals when compared to the unpressurized wines. These results indicate that pressure influences the white and red wine long term volatile composition, being this particularly evident for longer storage periods. The changes on the volatile composition of the pressurized wines, indicated that the HHP treatments accelerate the Maillard reactions, and the oxidation of alcohols and fatty acids, leading to wines with a volatile composition network approaching the characteristic of faster aged and/or thermally treated wines. The acceleration of Maillard reactions and phenolic compounds condensation by HHP treatments was also studied in model wine solutions (hydro alcoholic solution at acidic pH). The results showed that the high pressure treatment accelerated the Maillard reaction and this effect was quantifiable, mainly, after 6 months of storage. Pressurized model solutions presented higher concentration of 2-furfural, phenylacetaldehyde and benzaldehyde, when compared to the controls. In terms of phenolic compounds condensation reactions, the pressurized model wine solutions showed no relevant differences, when compared to controls. Therefore, it seems that the pressure treatment had a higher impact in terms of kineticks of reactions and in less extent in terms of different compounds formed. Lastly, the application of HHP treatments in winemaking to improve the properties of young wines was evaluated. For this propose, the effect of HHP treatments in the phenolic composition of a red wine was studied and compared with the effect of different oenological practices. Wines pressurized at 500 MPa for 5 min, and 600 MPa for 20 min, at 20 ºC, showed, after 5 months of storage, a lower monomeric anthocyanins (8-14%), phenolic acids (8-11%) and flavonols (14-22%) content, when compared to the unpressurized ones. The wine pressurized at 500 MPa presented a flavanols content and a degree of polymerization very similar to the wines treated by traditional aging processes. In terms of sensorial properties, the pressure treatments increased the cooked fruit aroma and decreased the floral and fruit odours and, in the case of the 600 MPa treatment, increased the bitterness. Therefore, the HHP treatments seem to promote reactions that are similar to those observed in wines treated with wood aging processes. In conclusion, the results presented in this thesis showed that HHP treatments accelerated the Maillard reaction and the polymerization reactions between phenolic compounds present in the wine, influencing the chemical and sensorial properties of wine. HHP can be potentially used to preserve or accelerate the wine aging process, producing wines with pleasant and distinct characteristics.
Durante os últimos anos, o uso de alta pressão hidrostática (APH) como tecnologia não-térmica para a preservação ou envelhecimento de vinho tem aumentado substancialmente na comunidade académica. No entanto, os vinhos tratados por APH têm sido analisados após o tratamento de pressão, não havendo referências sobre as suas propriedades durante o armazenamento. Os resultados apresentados nesta tese mostram que a aplicação de tratamentos de APH altera as propriedades químicas e sensoriais de vinhos ao longo do armazenamento. Os tratamentos de alta pressão hidrostática foram aplicados na vinificação para a preservação de vinho, como alternativa ao dióxido de enxofre, sendo o seu efeito avaliado nas propriedades físico-químicas e sensoriais de vinhos tintos e brancos durante o armazenamento em garrafa. Os tratamentos de alta pressão com 5 min de processamento e pressões de 425 e 500 MPa mostraram influenciar as características físico-químicas e sensoriais de vinhos tintos e brancos. No entanto, o efeito foi apenas percetível após pelo menos 6 meses de armazenamento. As alterações que ocorreram nas características do vinho tinto pressurizado, tais como a cor mais laranja-vermelho, menor atividade antioxidante (menos 15 a 27%), menor conteúdo de compostos fenólicos totais (menos 9%) e menor teor de antocianinas (menos 45-61%), foram devidas a um aumento das reacções de condensação de compostos fenólicos. O aumento destas reações de condensação levou à formação de compostos com maior grau de polimerização que se tornaram insolúveis no vinho ao longo do armazenamento, aumentando consequentemente a quantidade de depósito nos vinhos pressurizados. Em relação ao vinho branco, os vinhos pressurizados mostraram, depois de um ano de armazenamento, uma cor mais acastanhada, menor atividade antioxidante (menos 15%) e menor teor de compostos fenólicos totais (menos 10%) comparando com os vinhos não pressurizados. Estes resultados, juntamente com o baixo teor de aminoácidos livres (menos 15 a 20%) e um maior teor de furanos (até 70% mais) para os vinhos pressurizados após nove meses de armazenamento, levam a propor que os tratamentos de APH aceleraram as reações de Maillard que ocorrem durante o período de armazenamento do vinho. No entanto, ao contrário dos vinhos tintos pressurizados, os vinho brancos pressurizados não foram considerados adequados para comercialização como vinhos de mesa, visto que apresentavam uma cor acastanhada e um elevado aroma a fruta cozida, características estas de vinhos envelhecidos ou tratados termicamente.Adicionalmente, foi avaliado o impacto dos tratamentos de APH sobre a composição volátil dos vinhos tintos e brancos sem dióxido de enxofre durante o armazenamento em garrafas. Mais de 160 compostos voláteis, distribuídos por 12 grupos químicos, foram identificados em ambos os vinhos. No final do armazenamento, os vinhos pressurizados apresentaram um teor mais elevado de furanos, aldeídos, cetonas e acetais quando comparados com os vinhos não pressurizados. Estes resultados indicam que os tratamentos de APH influenciam a composição volátil de vinhos brancos e tintos, , sendo mais evidente em longos períodos de armazenamento. As mudanças na composição volátil dos vinhos indicaram que os tratamentos de APH aceleraram as reações de Maillard e também a oxidação de álcoois e ácidos gordos, originando vinhos com uma composição volátil próxima de vinhos com envelhecimento acelerado ou tratados termicamente. A aceleração das reações de Maillard e de polimerização dos compostos fénolicos causada pelos tratamentos de APH foi também estudada em soluções modelo de vinho (solução hidroalcoólica com pH ácido). Os resultados mostraram que o tratamento de APH acelera a reação de Maillard , sendo este efeito quantificado, apenas, após 6 meses de armazenamento. As soluções modelo de vinho pressurizadas apresentaram concentrações mais elevadas de 2-furfuraldeído, fenilacetaldeído e benzaldeído, em comparação com os controlos. Em termos de polimerização dos compostos fénolicos, as soluções modelo pressurizadas não apresentaram diferenças relevantes, em comparação com os controlos. Por conseguinte, os tratamentos de APH aparentem ter mais impacto em termos de modificações nas cineticas de reação do que na formação de novos compostos. Por último, a aplicação de tratamentos de APH foi estudada para melhorar as propriedades de vinhos jovens. Para este propósito, o efeito de tratamentos de APH na composição fenólica de um vinho tinto foi estudado e comparado com o efeito de diferentes práticas enológicas. Vinhos pressurizados a 500 MPa durante 5 min e a 600 MPa durante 20 min, a 20 ºC, mostraram depois de 5 meses de armazenamento um menor teor de antocianinas monoméricas (8-14%), ácidos fenólicos (8-11%) e flavonóis (14 -22%), quando comparados com os vinhos não-pressurizados. O vinho pressurizado a 500 MPa apresentou um teor de flavonóis e um grau de polimerização de taninos muito semelhante aos vinhos tratados por processos de envelhecimento tradicionais. Em termos de propriedades sensoriais, os tratamentos de pressão aumentaram o aroma de fruta cozida e diminuiram os aromas florais e frutados, tendo no caso do tratamento de 600 MPa sido verificado também um aumento da amargura. Assim sendo, os tratamentos de APH parecem promover reações que são semelhantes às observadas em vinhos tratados com processos de envelhecimento em madeira. Em conclusão, os resultados apresentados nesta tese mostram que a aplicação de tratamentos de APH acelera as reações de Maillard e a polimerização dos compostos fenólicos presentes no vinho, ao longo do armazenamento, alterando assim as propriedades químicas e sensoriais dos vinhos. A APH pode ser potencialmente utilizada para preservar ou acelerar o processo de envelhecimento de vinho tinto produzindo vinhos com características agradáveis e distintas.

Tyrimo objektas – melsvauogio sausmedžio 'Atut', 'Duet', 'Karina', 'Fialka', 'Dlinoplodnaja' ir 'Kalakolcik' veislių uogos. Tyrimo tikslas – parinkti konservavimo būdą ir įvertinti jo įtaką sausmedžio uogų kokybei. Tyrimo metodai: standartizuotais metodais buvo nustatyta uogų biocheminė sudėtis (askorbo rūgštis, mg 100 g-1; sausosios medžiagos, žalia ląsteliena, žali baltymai ir žali pelenai, proc.), juslinė analizė (skonis ir kvapas, tekstūra, išorinis patrauklumas), biometriniai duomenys (masė, ilgis ir skersmuo). Atlikta visų tyrimo duomenų statistinė analizė. Tyrimo rezultatai. Esmingai didžiausias vitamino C kiekis, nepriklausomai nuo konservavimo būdo, nustatytas 'Karina' veislės uogose, o 'Atut' veislės uogose esmingai didžiausias sausųjų medžiagų kiekis. Šaldytose 'Atut' veislės uogose buvo nustatyta esmingai daugiausiai žalios ląstelienos, žalių baltymų ir žalių pelenų, o liofilizuotose 'Kalakolcik' uogose žalių baltymų ir pelenų kiekiai. Geriausiomis juslinėmis savybėmis pasižymėjo 'Karina', 'Kalakolcik' ir 'Dlinoplodnaja' veislių uogos. Esmingai didžiausia šviežių uogų masė nustatyta 'Duet', o šaldytų ir liofilizuotų 'Atut' veislės uogų. Rekomenduojama sausmedžio uogas liofilizuoti, nes konservuojant šiuo būdu maksimaliai išsaugomos uogų juslinės savybės ir maistinė vertė. Nustatyta, kad sausmedžio uogų kokybė priklauso ir nuo veislės genetinių savybių ir nuo konservavimo būdo. Tyrimas parodė, kad 'Atut' ir 'Karina' veislių uogos, nepriklausomai nuo konservavimo... [toliau žr. visą tekstą]
Research object – six cultivars of blue-honeysuckle berries: 'Atut', 'Duet'‚ 'Karina', 'Fialka', 'Dlinoplodnaja' and 'Kalakolcik'. Research aim – to choose the method of preservation and to evaluate its influence on the quality of honeysuckle berries. Research methods: chemical composition of berries (the amount of ascorbic acid (mg 100 g-1), dry matter, crude fibre, crude protein, crude ash, %), sensory analysis (taste and aroma, texture, external attractiveness) and biometric indicators (weight, length and diameter) were evaluated using standardized methods. All research data was tested statistically. Research results. Independent of the method of preservation, 'Karina' berries were characterized by the highest amount of ascorbic acid, whereas 'Atut' had the highest amount of dry matter. The highest amount of crude fibre, crude protein and crude ash was related to frozen 'Atut' berries, meanwhile lyophilized 'Kalakolcik' berries contained the highest amount of crude protein and crude ash. 'Karina', 'Kalakolcik' and 'Dlinoplodnaja' berries were characterized by the best organoleptic properties. Fresh berries of 'Duet' cultivar as well as frozen and lyophilized berries of 'Atut' cultivar had the largest weight. It is recommended that honeysuckle berries be lyophilized since this particular way of preservation was characterized by the best sensory properties and nutritional value of berries. It was determined that the quality parameters of berries were affected by the genetic... [to full text]

This Project identified the relationships between storage conditions, dry matter losses (DMLs) caused by Fusarium species in cereal grains and mycotoxin contamination and assessed novel control strategies for post-harvest grain management including chemical control and ozone. F. graminearum, F. verticillioides and F. langsethiae were inoculated on wheat, maize and oats and stored under environmental conditions where marginal to optimum spoilage and mycotoxin contamination can occur. DMLs were calculated from the CO2 produced and were significantly correlated with deoxynivalenol (DON), zearalenone (ZEA), fumonisins (FUMs) and T-2 and HT-2 toxins respectively. Mycotoxin levels in wheat and maize exceeded the EU legislative limits with 0.9-1% DMLs. Therefore, CO2 monitoring during storage can indicate the level of contamination in a stored batch. Using CO2 production data at different water activity (aw) and temperature conditions, the environmental regimes at which F. langsethiae can grow and contaminate oats with T-2 and HT-2 toxins were identified for the first time. Five acids were examined in vitro and little effect was observed on Fusarium growth, in the aqueous form, while the effect on mycotoxin production varied. Dissolved in ethanol, adipic, fumaric and ferulic acids inhibited fungal growth and controlled DON and FUMs, but T-2 toxin was stimulated by the ethanol. Two garlic essential oils, propyl-propylthiosulfinate (PTS) and propyl propylthiosulfonate (PTSO) were studied for the first time. In vitro, 200 ppm reduced fungal growth (50-100%) and mycotoxin production by >90%. The efficacy was species-dependent. In naturally contaminated oats of 0.93 aw stored for 20 days, 16 ppm PTSO reduced T-2 and HT-2 toxins by 66% and ochratoxin A (OTA) by 88%, while 200 ppm PTS reduced OTA by 95%. In wheat, 100 ppm PTS reduced DON and ZEA and 300 ppm PTS reduced fumonisins by 40-80%. PTSO:PTS (1:1) at 400 and 600 ppm was very effective against DON and ZEA in wheat of 0.92 aw. Ozone (O3) exposure at 200 ppm for 30 min delayed Fusarium spore germination on media of 0.98 aw and inhibited germination at 0.94 aw. O3 was more effective against fungal spores than mycelium and little effect was observed on growing cultures. In vitro, mycotoxin production after exposure depended on the stage of life of the fungi. O3 reduced fungal populations in grains. Mycotoxin production in wet grains treated with 100-200 ppm O3 for 60 min and stored for up to 30 days was reduced or completely inhibited, depending on the species and the exposure system. Simultaneous drying of the grain due to the O3 passage was observed.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
Brazil is a country of great diversity in species of native fruits, yet little explored, but with huge agro-industrial and nutritional potential, being mangaba one of these promising fruit. Research indicates that the intake of conventional, exotic and native fruits provide not only essential nutrients, but also bioactive compounds that promote beneficial effects on human health, reducing the risk of chronic diseases and even cancer, due to the interaction between these compounds and their antioxidant potential. This study aimed to evaluate the behavior of bioactive compounds and antioxidant activity in raw fruits mangaba (Hancornia speciosa Gomes), and the influence of conservation methods: freezing, freeze-drying and foam layer before these biocompounds. The samples were evaluated at Chemistry and Biochemistry Laboratory of Food of Faculty of Pharmacy of Federal University of Goiás, as regard of: ascorbic acid, phenolic compounds, carotenoids and total antioxidant activity by DPPH methods, ABTS and FRAP. Analyses were performed in triplicate for each sample, and the results were expressed as mean ± standard deviation. The results showed significant correlation between the content of total phenolic compounds and total antioxidant activity by FRAP method, showing that ascorbic acid content, contributed to the antioxidant activity of the samples. Thus, there is a possibility of using mangaba, both for consumption and fresh using, referred to as different methods of preservation, possibly enabling the use of the fruit as a functional food.
O Brasil é um país com grande diversidade em espécies de frutas nativas, ainda pouco exploradas, mas com enorme potencial agroindustrial e nutricional, sendo a mangaba, uma destas frutíferas promissoras. Pesquisas apontam que a ingestão de frutas convencionais, exóticas e nativas fornecem não somente os nutrientes essenciais, mas também, compostos bioativos que promovem efeitos benéficos à saúde humana, reduzindo o risco de doenças crônicas não transmissíveis e até mesmo o câncer, devido à interação entre estes compostos e seu potencial antioxidante. Este estudo teve como proposta, avaliar o comportamento dos compostos bioativos e da atividade antioxidante em frutos in natura de mangaba (Hancornia speciosa Gomes), bem como a influência dos métodos de conservação: congelamento, liofilização, secagem em camada de espuma, frente a estes biocompostos. As amostras foram avaliadas no Laboratório de Química e Bioquímica de Alimentos, da Faculdade de Farmácia, da Universidade Federal de Goiás, quanto ao teor de: ácido ascórbico, compostos fenólicos totais, carotenoides e atividade antioxidante total pelos métodos DPPH, ABTS e FRAP. As análises foram realizadas em triplicata, para cada amostra, e os resultados expressos em média ± desvio padrão. Os resultados demonstraram correlação significativa entre o conteúdo de compostos fenólicos totais e a atividade antioxidante total pelo método do FRAP, dem onstrando que o teor de ácido ascórbico, contribuiu para a atividade antioxidante das amostras analisadas. Assim, verifica-se a possibilidade do uso da mangaba, tanto para o consumo na forma in natura, quanto submetido aos diferentes métodos de conservação, possibilitando possivelmente a utilização deste fruto como alimento funcional.

Ce travail de thèse consiste en l’élaboration d’une méthodologie d’étude de monuments historiques, appliquée au château de Chambord. Il s’agit de mettre en place le carnet de santé de l’édifice, et de le compléter par une expérimentation en laboratoire, afin de réaliser un diagnostic d’altération.Les archives historiques concernant le château ont été rassemblées et analysées pour concevoir des cartographies de dates de pose et de nature des pierres. L’examen in situ des façades a ensuite conduit à réaliser des cartographies d’altération. La synthèse des informations concernant le passé et le présent du monument a permis d’établir une liste des principaux facteurs environnementaux associés aux altérations, de même que la chronologie de leur développement, pour ainsi aboutir à une première estimation des cinétiques de progression.C’est la desquamation en plaques, détérioration courante du tuffeau, à la fois la plus dommageable et la plus complexe, qui a été ciblée pour le diagnostic d’altération. Les analyses physico-chimiques réalisées sur des prélèvements in situ ont conduit à l’identification systématique du gypse dans les fissures des desquamations. Des simulations expérimentales ont été mises en place pour appréhender le rôle du gypse, son mode de transport et son origine. La pollution atmosphérique mettant en oeuvre du SO2 gazeux reproduit bien la distribution du gypse telle que mesurée dans les desquamations en plaques observées au château de Chambord. Un mécanisme incluant ce phénomène a été proposé, pour expliquer le développement de cette altération, et qui pourrait être à la base des prévisions de l’évolution des altérations, afin d’envisager le futur du monument
This thesis is dedicated to the establishment of a methodology to study the built cultural heritage, applied to the castle of Chambord. It consists in realizing the health record of the monument, and completing it by an experimental sequence in laboratory, in order to provide a diagnosis of the state of degradation.Historical archives about the castle were gathered and analysed to obtain mappings of dating and nature of stone. By mean of in situ observations, a mapping of degradation has been added. A synthesis of the information concerning the past and the present of the monument allowed establishing a list of the main factors associated to degradations and to a chronology of development of these degradations, so as to estimate their kinetics.Spalling, which is the most damaging and complex usual degradation, has been chosen as case of study for the diagnosis of degradation. The physic-chemical characterisations made on in situ coring lead to systematically found gypsum in spalling’s cracks. Various artificial ageing tests have been performed to enlighten the role of gypsum, its transport mode, and its origin. Atmospheric pollution including gaseous SO2 reproduces well the distribution of gypsum observed in spalling at Chambord. A global mechanism taking into account this phenomenon has been proposed to clarify the development of this degradation

This work studies the impact of two traditional Romanian treatments, Red Petroleum and Propolis, in terms of real efficiency and consequence on the wooden artifacts. The application of these solutions is still a widely adopted and popular technique in preservative conservation but the impact of these solutions is not well known. It is important to know the effect of treatments on chemical-physical and structural characteristics of the artifacts, not only for understanding the influence on present conditions but also for foreseeing the future behavior. These treatments with Romanian traditional products are compared with a commercial antifungal product, Biotin R, which is utilized as reference to control the effectiveness of Red Petroleum and Propolis. Red Petroleum and Propolis are not active against mould while Biotin R is very active. Mould attack is mostly concentrated in the painted layer, where the tempera, containing glue and egg, enhance nutrition availability for moulds. Biotin R, even if is not a real insecticide but a fungicide, was the most active product against insect attack of the three products, followed by Red Petroleum, Propolis and untreated reference. As for colour, it did not change so much after the application of Red Petroleum and Biotin R and the colour difference was almost not perceptible. On the contrary, Propolis affected the colour a lot. During the exposure at different RH, the colour changes significantly at 100% RH at equilibrium and this is mainly due to the mould attack. Red Petroleum penetrates deeply into wood, while Propolis does not penetrate and remains only on the surface. However, Red Petroleum does not interact chemically with wood substance and it is easy volatilized in oven-dry condition. On the contrary Propolis interacts chemically with wood substance and hardly volatilized, even in oven-dry condition and consequently Propolis remains where it penetrated, mostly on the surface. Treatment by immersion has impact on wood physical parameters while treatment by brushing does not have significant impact. Especially Red Petroleum has an apparent impact on moisture content (MC) due to the penetration of solution, while Propolis does not penetrate so much and remains only on surface therefore Propolis does not have so much impact as Red Petroleum. However, if the weight of the solution penetrated in wood is eliminated, there is not significant difference in MC between treated and untreated samples. Considering physical parameters, dimensional stability is an important parameter. The variation of wood moisture content causes shrinkages/swelling of the wood that polychrome layer can only partially follow. The dimension of wooden supports varied under different moisture conditioning; the painted layer cannot completely follow this deformation, and consequently a degradation and deterioration caused by detachment, occurs. That detachment affects the polychrome stratification of the panel painting and eventually the connections between the different layer compositions of the panel painting.

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico
The food industry uses chemical additives to extend the shelf life of its products and maintain their sensory and microbiological characteristics acceptable. However, the presence of preservatives in foods may interfere in the quantification of total antioxidant activity. Therefore, this study aimed to evaluate the influence of food preservatives on total antioxidant activity and on the sensory and microbiological quality of acerola tropical juice. The fruits were washed, sanitized (200 ppm sodium hypochlorite), pulped and then were formulated with water and its specific preservatives. The juices were heat treated (90ÂC/60 seconds) and hot filled in glass bottles, which were closed, cooled until 35ÂC and stored at 25ÂC for 180 days. The formulations tested were: control juice without additive (C); juice with addition of 0.004 g/100 mL of sodium metabisulphite (SMS); juice with addition of 0.08 g/100 mL of potassium sorbate (SSP); juice added of 0.05 g/100 mL of sodium benzoate (SBS); juice added of 0.002 g/100 mL of sodium metabisulfite and 0.04 g/100 mL of potassium sorbate S(MS+ SP); juice with addition of 0.002 g/100 mL of sodium metabisulfite and 0.025 g/100 mL of sodium benzoate S(MS + BS). It was carried out chemical determinations for ascorbic acid, total carotenoids, total anthocyanins, total extractable polyphenolics and total antioxidant activity by ABTS and DPPH methods. Commercial sterility testing was performed on samples to determine the hygienic and sanitary processing and to check for any microbiological changes. In sensory acceptance tests were used acerola nectars, prepared by dilution from the acerola tropical juice and added sucrose to obtain 11 ÂBrix, using a 9-point hedonic scale for flavor, color, aroma, sweetness, appearance, body and overall impression. The experiments were performed at three time points (0, 90 and 180 days) and the determinations were made in triplicate. The results were analyzed by the interaction between the juice type and storage time. Regarding anthocyanins content, all samples showed an average of 1.0 mg/100mL (P> 0.05). The acid ascorbic contents remained stable during the storage and ranged from 256.22 mg/100mL (C juice) to 301mg/100mL (SMS and SSP juices). The total carotenoid in treatments with or without preservatives did not vary significantly among themselves, with mean values of 0.04 mg/100mL. The yellow flavonoids showed no significant difference between the juice type (P> 0.05), averaging 5.30 mg/100 mL. For soluble dark pigments, SMS obtained the lowest range in absorbance at 90 days time (0.170 to 0.240), and greater variation for the control juice (from 0.230 to 0.320). All samples showed high losses of phenolics during storage, observing greater losses at times of 0 and 90 days, which ranged from 36.59% for S(BS + MS) and 42.97% for SMS. There was a significant variation of total antioxidant activity with time by the DPPH test (P≤0.05). The values ranged from 877.41 to 978.44 g/g DPPH for C and SMS juices, respectively. A similar behavior was observed for contents analyzed by the ABTS testing: 58.46 mM Trolox/g for SMS and 49.80 mM Trolox/g for control juice. A significant and positive correlation was verified between polyphenols and ABTS (r = 0.78) and DPPH (r = 0.44); anthocyanins and ABTS (r = 0.39) and DPPH (r = 0.44). Yellow flavonoids and ABTS and DPPH assays were negatively and significantly correlated (r = -0.83 and r = -0.52), respectively. There was no significant correlation between ascorbic acid and ABTS and DPPH assays. There was no significant interaction between any treatment and storage time (P> .05). Sodium metabisulphite and its combinations did not influence sensorial acceptance of acerola nectars, with assessments within the acceptable range for all analyzed attributes along storage time. The potassium sorbate and sodium benzoate singly were the additives that contributed most to a higher rejection sensory of products. The employed chemical preservatives, associated with the heat treatment, were effective for maintaining the commercial sterility of acerola tropical juices.
A indÃstria de alimentos utiliza-se de conservantes quÃmicos para prolongar a vida Ãtil de seus produtos e manter suas caracterÃsticas sensoriais e microbiolÃgicas aceitÃveis. Contudo a presenÃa desses conservantes nos alimentos pode interferir na quantificaÃÃo da atividade antioxidante total. Portanto, este trabalho objetivou avaliar a influÃncia dos conservantes alimentares na atividade antioxidante total, na qualidade sensorial e microbiolÃgica de sucos tropicais de acerola. As frutas foram lavadas, sanitizadas (200mg/L de cloro ativo) e despolpadas, em seguida, formuladas com Ãgua e seus conservantes especÃficos. Os sucos foram tratados termicamente (90ÂC/60 segundos) e acondicionados a quente em garrafas de vidro, que foram fechadas, resfriadas atà 35ÂC e armazenadas à temperatura de 25ÂC por 180 dias. As formulaÃÃes testadas foram: suco controle, sem aditivo (C); suco com adiÃÃo de 0,004 g de metabissulfito de sÃdio/100 mL (SMS); suco com adiÃÃo de 0,08g sorbato de potÃssio /100 mL de (SSP); suco adicionado de 0,05g de benzoato de sÃdio /100 mL (SBS); suco com 0,002g de metabissulfito de sÃdio e 0,04 g/100 mL de sorbato de potÃssio/100 mL S(MS+SP)); suco com adiÃÃo de 0,002g/100 mL de metabissulfito de sÃdio e 0,025 g/100 mL de benzoato de sÃdio S(MS+BS). Foram realizadas determinaÃÃes quÃmicas de Ãcido ascÃrbico, carotenÃides totais, antocianinas totais, polifenÃis extraÃveis totais e quantificaÃÃo da atividade antioxidante total pelos mÃtodos ABTS e DPPH. Foi realizado o teste de esterilidade comercial nas amostras para determinar as condiÃÃes higiÃnico-sanitÃrias do processamento e verificar as possÃveis alteraÃÃes microbiolÃgicas. Os testes sensoriais de aceitaÃÃo foram utilizados nÃctares de acerola, preparados por diluiÃÃo a partir do suco tropical de acerola e adicionado de sacarose atà obtenÃÃo de 11 ÂBrix, os quais foram avaliados quanto aos atributos impressÃo global, cor, aparÃncia, aroma, doÃura, sabor e corpo utilizando uma escala hedÃnica estruturada de nove pontos. Os experimentos foram realizados em trÃs tempos (0, 90 e 180 dias) e realizados em triplicata. Os resultados foram tratados por anÃlise de interaÃÃo entre os diferentes tratamentos e tempo de armazenamento. Para o teor de antocianinas, todas as amostras apresentaram mÃdia de 1,0mg/100g (P>0,05). O teor de Ãcido ascÃrbico se manteve estÃvel durante o armazenamento, variando de 256,22 mg/100mL para o suco C, a 301mg/100mL, para os sucos SMS e SSP. Os teores de carotenÃides totais nos tratamentos com ou sem conservantes nÃo diferiram entre si (P>0,05), apresentando valor mÃdio de 0,04mg/100mL. Os flavonoides amarelos nÃo apresentaram diferenÃa significativa (P>0,05), apresentando mÃdia de 5,30mg/100mL. Para pigmentos escuros solÃveis o SMS obteve a menor variaÃÃo na absorbÃncia no tempo de 90 dias (0,170 a 0,240), e a maior variaÃÃo para o suco controle (0,230 a 0,320). Todas as amostras apresentaram perdas elevadas de fenÃlicos durante o armazenamento, observando-se perdas maiores entre 0 e 90 dias, que variaram de 36,59% para S(MS+BS) e 42,97% para SMS. Houve variaÃÃo significativa com o tempo para a atividade antioxidante total pelo ensaio DPPH (P≤0,05). Os valores variaram entre 877,41 e 978,44 g/g DPPH para os sucos C e SMS, respectivamente. Comportamento semelhante foi observado para os teores analisados pelo mÃtodo ABTS, observando-se para o SMS, 58,46 ÂM Trolox/g; e para o suco controle, 49,80 ÂM Trolox/g. A correlaÃÃo positiva e significativa foi verificada entre polifenÃis e o ensaio ABTS (r = 0,78) e para DPPH (r = 0,44). Antocianinas totais e ABTS (r = 0,39) e DPPH (r = 0,44). Os flavonÃides amarelos e os ensaios ABTS e DPPH se correlacionaram negativamente e significativamente (r = -0,83 e r= -0,52; respectivamente). NÃo foi observada interaÃÃo significativa entre os tratamentos e os tempos de armazenamento (P > 0,05). O metabissulfito de sÃdio e suas combinaÃÃes nÃo influenciaram na aceitaÃÃo sensorial dos nÃctares de acerola, com avaliaÃÃes dentro da faixa de aceitaÃÃo para todos os atributos analisados ao longo do tempo de armazenamento. Os aditivos sorbato de potÃssio e benzoato de sÃdio isoladamente contribuÃram para uma maior rejeiÃÃo sensorial dos produtos. Os conservantes quÃmicos utilizados, associados ao tratamento tÃrmico empregado, foram eficientes para a manutenÃÃo da esterilidade comercial dos sucos tropicais de acerola.

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Por causa do alto custo para obter um produto de madeira proveniente de uma espécie arbórea nativa no Brasil, o uso de materiais alternativos, que seja de fontes renováveis e que possa substituir estas espécies vem ganhando espaço no mercado nacional, e o bambu se destaca nesse novo cenário. Este trabalho teve como objetivo avaliar a qualidade e a eficiência do tratamento preservativo de duas espécies de bambu (Dendrocalamus giganteus e Bambusa vulgaris) pelo emprego de três métodos de tratamento: transpiração (diafragma íntegro e diafragma rompido), imersão prolongada e Boucherie modificado. Para tanto, foram coletadas hastes de touceiras do sul do Estado do Espírito Santo. As hastes foram transformadas em colmos de 2,0 m de comprimento e tratadas em solução de 1 e 3% de ingredientes ativos (i.a.) do produto comercial MOQ OX 50 , à base de cobre, cromo e boro (CCB). Nos métodos por transpiração e imersão prolongada os colmos foram expostos nas soluções por períodos de 5, 10 e 15 dias, já no método de Boucherie modificado não houve divisão do tratamento entre os tempos. O período entre o corte e o tratamento foi inferior a 24 h. Foi avaliada a qualidade do tratamento por meio da penetração do CCB em três posições nos colmos; 0,5 m (base), 1,0 m (meio) e 1,90 m (topo) e pela retenção de i.a. na posição da base. A eficiência dos tratamentos foi analisada por meio da resistência dos bambus tratados aos ensaios com os fungos (Postia placenta e Polyporus fumosus), com o térmita subterrâneo (Nasutiternes sp.) e com coleópteros (Dinoderus minutus). A partir dos resultados obtidos foi observado que, em média, houve uma maior penetração de i.a. na base dos colmos, que a retenção foi abaixo da recomendada pelas normas brasileiras para madeira, e para ambas as espécies de bambu tratadas a perda de massa quando submetidos ao ataque dos fungos, cupim e coleópteros foi baixa. Dentre os tratamentos, a aplicação do método de transpiração com o diafragma rompido em concentração de 3% de i.a. e com duração de 15 dias conferiu, para as duas espécies, as maiores médias de penetração e retenção, bem como menores valores de perda de massa nos ensaios biológicos
Because the high cost to get a wood product coming from a native tree species in Brazil, the use of alternative materials that come from renewable sources that can replace these species has been gaining ground in the domestic market, and bamboo stands in this new scenario. This study aimed to evaluate the quality and efficiency of the preservative treatment of two species of bamboo (Bambusa vulgaris and Dendrocalamus giganteus) by employing three methods of treatment; transpiration (diaphragm intact and ruptured diaphragm), long-term immersion and modified Boucherie. To this end, were collected clumps of stems of southern State of Espírito Santo. Stems were transformed into culms of 2 meters long, solution treated at 1 and 3% active ingredient (a.i.) of the commercial product MOQ OX 50 , based on copper, chromium and boron (CCB). For transpiration and long-term immersion methods the culms were exposed to the solutions for periods of 5, 10 and 15 days, Boucherie now modified method of treatment there was no division between times. The period between cutting and treatment was less than 24 h. It was evaluated the quality of the treatment by penetration of the CCB at three positions in stems, 0,5 m (bottom), 1,0 m (middle) and 1,90 m (top) and the retention of a.i. the bottom region. The efficiency of the treatments was analyzed by resistance of bamboos treated with the test fungi (Postia placenta and Polyporus fumosus), with the subterranean termite (Nasutiternes sp.) and coleopteran (Dinoderus minutus). From the results it was observed that, on average, there was a higher penetration of the a.i. at the bottom region of the stems, retention was lower than recommended by Brazilian standards, and both species of bamboo treated showed low mass loss when subjected to the attack of fungi, termites and beetles. Among the treatments, of transpiration with the diaphragm ruptured at 3% concentration of a.i. and time of 15 days gave, for both species, shows the higher average penetration and retention as well as lower values of weight loss in biological tests

Mestrado de dupla diplomação com a Université Libre de Tunis
Bee bread is an important beehive product, and it is growing in commercial interest due to its high nutritional value and richness in bioactive compounds, and it is thus considered as a human functional food. The rich composition of bee bread with different nutrients can result in microbial growth and spoilage, especially when handling practices are not approprite. This work intends to evaluate the impact of different preservation methods - freezing, room temperature, oven drying at 30 °C, and freeze drying - on bee bread physicochemical characteristics and microbial stability, during a storage period of six months. Samples were analysed before the application of the treatments, immediately after the application of the treatments (T0), and after one (T1), three (T3) and six (T6) months of storage. For each time point of analysis, the samples were analyzed for several parameters: microbiological (aerobic mesophiles, lactic acid bacteria, yeasts, moulds, and coliforms), physical-chemical (pH, water activity, moisture content, proteint content, lipid content and ash) and bioactive (total phenolic compounds and antioxidant activity). The techniques of oven-drying and freeze-drying were the most effective in reducing the initial moisture content of bee bread from 16.5% to 9.9% and 11.0%, respectively. These reductions were also evident in bee bread water activity, which was reduced from 0.57 to approximately 0.36, for both preservation techniques. Overall, the various preservation treatments significantly affected the nutritional composition of bee bread. This was particularly evident when room temperature drying was used, causing an increase of 80% on bee bread total lipid content, after a storage period of 3 months. The total phenolic content was also influenced by the preservation treatment applied to bee bread, particularly for freeze-drying, which caused a reduction of approximately 40%, after 1 month of storage, reflected on an increase of 50% for EC50 value, evidencing a decrease in the bee bread antioxidant activity that continued during the whole 6 month storage period. The results obtained for microbial analysis showed that the frozen samples have the highest microbial loads. The preservation at room temperature without previous treatment presented similar or better preservation efficiency compared to oven drying and freeze drying. No significant differences were observed between these treatments in most situations, except for the yeast counts, which the results presented a significant differences between all the treatment througout storage. Overall, each preservation technique acted differently on the various parameters over time. From a chemical perspective, after six months of storage there was no significant difference between treatments. From a microbial point of view, freezing was the least adequate preservation technique, while the remaining preservation techniques showed similar good product stability. Given the results obtained in the present study, preservation at room temperature without any previous treatment seems to be an adequate technique for the preservation of bee bread under the tested conditions. Further studies are required to elucidate the effect of different levels of pH and water activity on the stability of non-treated bee bread.
O pão de abelha é um importante produto da colmeia, e apresenta crescente interesse comercial devido à sua riqueza nutricional e elevada bioatividade, sendo por isso considerado um alimento funcional. A riqueza nutricional do pão de abelha pode resultar em crescimento microbiano e consequente deterioração, especialmente quando as práticas de manipulação são inadequadas. O presente trabalho tem como objetivo a avaliação do impacto de vários métodos de preservação – congelação a -20 ºC, conservação à temperatura ambiente, secagem em estufa a 30 ºC, e liofilização – nas características fisico-químicas e estabilidade microbiana, durante um período de armazenamento de seis meses. Amostras de pão de abelha foram analisadas antes da aplicação dos tratamentos, imediatamente após a aplicação (T0), e após um (T1), três (T3) e 6 (T6) meses de armazenamento. Em cada tempo de análise, foram avaliados os seguinte parâmetros: microbiológicos (mesófilos aeróbios, bactérias do ácido lático, leveduras, bolores, coliformes), físico-químicos (pH, atividade de água, conteúdo em água, conteúdo proteico e lipídico, cinzas), e bioativos (compostos fenólicos totais e atividade antioxidante). As técnicas de secagem em estufa e liofilização foram os mais eficientes na redução do conteúdo em água de 16.5% para 9.9% e 11.0%, respetivamente. A atividade de água sofre redução de 0.57 para 0.36. Em geral, os vários tratamentosafetaram de forma significativa a composição nutricional do pão de abelha. Na conservação à temperatura ambiente, verificou-se um aumento de 80% no conteúdo lipídico das amostras após três meses de conservação. O conteúdo fenólico total foi igualmente afetado, em particular no tratamento por liofilização, que conduziu a uma redução de 40% após um mês de armazenamento e consequente aumento de 50% do valor EC50, evidenciando uma redução da atividade antioxidante do pão de abelha ao longo dos seis meses de conservação. Os resultados obtidos na análise microbiana mostraram que as amostras congeladas apresentaram as mais elevadas cargas microbianas. A preservação à temperatura ambiente sem qualquer tratamento prévio apresentou uma eficiência de conservação equivalente ou melhor do que a secagem em estufa e a liofilização. Não se registaram diferenças significativas entre tratamentos, exceto no caso das leveduras onde se verificou que houve diferenças significativas entre os tratamentos ao longo do armazenamento. Em geral, as técnicas de conservação tiveram diferentes efeitos sobre o pão de abelha nos vários parâmetros e ao longo do tempo. No entanto, não foram demonstradas diferenças significativas entre tratamentos para os parâmetros químicos após seis meses de conservação. Em termos microbiológicos, a congelação mostrou ser o método de preservação menos adequado, enquanto os restantes tratamentos demonstraram ser equivalentes na manutenção da estabilidade microbiológica do produto. Em face dos resultados obtidos, e considerando as condições testadas, a conservação do pão de abelha à temperatura ambiente sem tratamento prévio parece ser um método adequado. Será no entanto importante o desenvolvimento de estudos complementares que permitam elucidar o efeito de diferentes níveis de pH, atividade de água e qualidade microbiana do produto na estabilidade de pão de abelha conservado à temperatura ambiente sem tratamento prévio.
Trabalho financiado pelo Projeto DivInA (PDR2020-101-031734), no âmbito de uma iniciativa comunitária promovida pelo PDR2020 e cofinanciada pelo FEADER, Portugal 2020. Este trabalho foi também parcialmente financiado pelo CIMO UID/AGR/00690/2019) através do FEDER no âmbito do PT2020.

Melanin is a ubiquitous biological pigment found in bacteria, fungi, plants, and animals. It has a diverse range of ecological and biochemical functions including display, evasion, photoprotection, detoxification, and metal scavenging. Two forms of melanin produced from different molecular precursors are present in nature - eumelanin (dark brown-black in color) and pheomelanin (orange-red in color). Both eumelanin and pheomelanin are complex highly cross-linked biopolymers that are found intertwined with proteins, lipids, and metal ions in nature.

Recent reports have used morphological evidence to suggest the presence of melanin in the fossil record. These studies have been met with criticism due to their lack of chemical evidence to support melanin identification. This dissertation describes chemical approaches to unambiguously verify the presence of melanin in the fossil record and characterize the ancient pigment. It also explores the limitations for the survival of melanin in the fossil record and the possibility that melanin acts as a protective matrix to preserve other biomolecules that are embedded in the pigment.

Melanin has unique chemical signatures that are commonly used to characterize and compare the pigment of modern organisms. We applied these chemical approaches to the study of fossil pigmentation. Analysis of the black pigmentation of two > 160 million year old (Mya) Jurassic cephalopod ink sacs provided the first conclusive evidence for eumelanin in the fossil record. The preserved fossil eumelanin was then compared to modern cephalopod eumelanin from Sepia officinalis. Using these chemical approaches we found that fossil eumelanin was chemically and morphologically identical to S. officinalis eumelanin.

Although there is mounting chemical evidence for the presence and preservation of melanin in the fossil record, there is very little data constraining its long-term survival. We applied the analytical approaches designed to study fossil melanins and techniques used to study fossil sediments to compare the fossil inks from three deposits of similar age and lithology, but different maturation histories. Specifically, two ~ 180 Mya fossil ink sacs from a site that has entered the oil window in Holzmaden, Germany were compared to the previously analyzed fossil inks from two less mature sites in southern England. The chemistry of eumelanin was shown to alter at the onset of the oil window regardless of the age of the specimen. The decrease in surviving melanin was accompanied by an increase in the relative abundance of organic macromolecular material (kerogen), but no consistent change in melanin morphology.

Finally, the role of melanin as a matrix that enhances the preservation of other biomolecules in the fossil record was considered. Proteins, commonly associated with melanin in modern organisms, were discovered in the aforementioned fossil ink sacs during full-scale chemical analysis. The amino acid profile of the protein in each fossil specimen was determined with an amino acid analyzer and compared to the amino acid profile the protein in modern S. officinalis. Statistical analysis of the amino acid distributions indicated that there is no significant difference between the amino acid profile of modern and fossil melanins. In order to verify the ancient origin of the amino acids in the fossil ink sacs, the ratio of D/L amino acid isomers was determined. While the proteins of living organisms consist of only L-amino acids, post-mortem the amino acids slowly convert from L to D form until they reach equilibrium (D/L = 1). This process is called racemization. The amino acids in the fossil ink sacs were racemized, which suggests their ancient origin. This marks the oldest determination of protein in a fossil system and provides evidence that the longevity of proteins may be enhanced when associated with melanin.

Dissertation

Propolis is a resin made by honeybees from multiple plant sources surrounding the hive. Therefore, each type of propolis from different regions has intrinsic characteristics related to their chemical composition, such as antifungal, antioxidative properties, and extrinsic such as color, both specific to their botanical origin. Thus, propolis can be regarded as a functional food with preservative properties offering an alternative to the concern of the global and growing use of synthetic preservatives considerably harming human health. The aim of this work was to study three types of propolis, namely, Portuguese propolis (from Populus sp.), Brazilian red propolis (from Dalbergia ecastophyllum), and Brazilian green propolis (from Baccharis dracunculifolia) in order to evaluate the antifungal potential for its application as a preservative in food. For that, the chemical composition was characterized by LC/DAD/ESI-MSn. Also, the total phenolic content, flavonoids and antioxidant activity was evaluated through UV-Vis spectrophotometry. Concerning the antifungal properties, the values differed in relation to the types of fungi, to the inoculating concentration and mode of action. With this in mind, an analysis of their antifungal activities at two levels of concentration (0.5-1.5 g/L and 5-15 g/L) was previously evaluated in vitro, with the aim of selecting the best concentration of inhibition of the rotting diameter of two types of grapes, namely, red and white. Subsequently, different fungi were used to test the activity of the aforementioned propolis, namely, Alternaria sp., Botrytis cinerea, Cladosporium sp., Penicillium sp. 2, Aspergillus carbonarius MUM04.46, and Aspergillus carbonarius MUM04.52. This last experiment made it possible to measure the rotting diameter of each grape and to evaluate the antifungal capacity of each type of propolis, with the final aim of using it to design an effective product that can extend the shelf life of food.
A própolis é uma resina produzida pelas abelhas a partir de múltiplas fontes vegetais ao redor da colmeia. Portanto, cada tipo de própolis de diferentes regiões possui características intrínsecas relacionadas à sua composição química, como antifúngica, propriedades antioxidantes, e extrínsecas como a cor, ambas específicas à sua origem botânica. Assim, a própolis pode ser considerada um alimento funcional com propriedades conservantes, oferecendo uma alternativa à preocupação mundial e crescente do uso de conservantes sintéticos que prejudicam consideravelmente a saúde humana. O objetivo deste trabalho foi estudar três tipos de própolis, a saber, própolis portuguesa (de Populus sp.), própolis vermelha brasileira (de Dalbergia ecastophyllum) e própolis verde brasileira (de Baccharis dracunculifolia), a fim de avaliar o potencial antifúngico para sua aplicação como um conservante em alimentos. Para isso, a composição química foi caracterizada por LC/DAD/ESI-MSn. Também os compostos fenólicos totais, flavonoide totais e atividade antioxidante foi avaliada por espectrofotometria de UV-Vis. Em relação às propriedades antifúngicas da própolis, os valores vão depender dos tipos de fungos, da concentração de inoculação e do modo de ação. Tendo isto em mente, foi efetuada uma análise in vitro da atividade antifúngica em dois níveis de concentração (0,5-1,5 g/L e 5-15 g/L), com o objetivo de selecionar a melhor concentração de inibição do diâmetro de apodrecimento de dois tipos de uvas, tintas e brancas. Posteriormente, diferentes fungos foram utilizados para testar a atividade da própolis, nomeadamente, Alternaria sp., Botrytis cinerea, Cladosporium sp., Penicillium sp. 2, Aspergillus carbonarius MUM04.46 e Aspergillus carbonarius MUM04.52. Esta última experiência possibilitou medir o diâmetro de apodrecimento de cada uva e avaliar a capacidade antifúngica de cada tipo de própolis, com o objetivo final de usar essa informação para desenvolver um produto eficaz que possa prolongar a vida útil dos alimentos.
Trabalho financiado pelo Projeto DivInA (PDR2020-101-031734), no âmbito de uma iniciativa comunitária promovida pelo PDR2020 e cofinanciada pelo FEADER, Portugal 2020. Este trabalho foi também financiado pelo projeto GreenHealth, financiado pelo Fundo Europeu de Desenvolvimento Regional (ERDF) através do Programa Operacional Regional Norte 2020. Agradecimento à Fundação para a Ciência e a Tecnologia (FCT, Portugal) e aos fundos nacionais FCT/MCTES pelo apoio financeiro ao CIMO (UIDB/00690/2020).

Impressive examples of the generation of hierarchically-patterned, three-dimensional (3-D) structures for the control of light can be found throughout nature. Morpho rhetenor butterflies, for example, possess scales with periodic parallel ridges, each of which consists of a stack of thin (nanoscale) layers (lamellae). The bright blue color of Morpho butterflies has been attributed to controlled scattering of the incident light by the lamellae of the wing scales. Another stunning example is the frustule (microshell) of the Coscinodiscus wailesii diatom, which is capable of focusing red light without possessing a traditional lens morphology. The photonic structures and the optical behaviors of Morpho butterflies and Coscinodiscus wailesii diatoms have been extensively studied. However, no work has been conducted to shift such light manipulation from the visible to the infrared (IR) range via shape-preserving conversion of such biogenic structures. Controlling IR radiation (i.e., heat) utilizing biogenic or biomimetic structures can be of significant utility for the development of energy-harvesting devices. In order to enhance the optical interaction in the IR range, inorganic replicas of biogenic structures comprised of high-refractive-index materials have been generated in this work. Such replicas of Morpho rhetenor scales were fabricated via a combination of sol-gel solution coating, organic pyrolysis, and gas/solid reaction methods. Diatomimetic structures have also been generated via sol-gel coating, gas/solid reaction, and then patterning of pore arrays using focused ion beam (FIB) milling.

Throughout the sol-gel solution coating and chemical conversion steps of the processes developed in this study, attention was paid to preserve the starting shapes of the nanopatterned, microscale biogenic or biomimetic structures. Factors affecting such shape preservation included the thicknesses and uniformities of coatings applied to the biogenic or biomimetic templates, nano/microstructural evolution during thermal treatment, and reaction-induced volume changes. A conformal surface sol-gel (SSG) coating process was developed in this work to generate oxide replicas of Morpho rhetenor butterfly scales with precisely-controlled coating thicknesses. The adsorption kinetics and relevant adsorption isotherm of the SSG process were investigated utilizing a quartz crystal microbalance. Analyses of thermodynamic driving forces, rate-limiting kinetic steps, and volume changes associated with various chemical reactions were used to tailor processing parameters for optimized shape preservation.

Collections of chemicals are assemblies of substances associated to chemical operations. These collections often have a large historical significance and can be found in departments, research institutions, schools or other spaces. So far, seldom dedicated studies have been made, both to the materiality of these collections, as well as for their conservation. For this dissertation, the glass containers in the collection of historical chemicals from the National Museum of Natural History and Science from the University of Lisbon (MUHNAC) are studied, as they are the largest storage material found in the collection and present signs of active deterioration, in the form of corrosion patterns. This research followed a three-fold approach – a collection survey was performed to assess the collection’s dimension; followed by a full conservation assessment of the corrosion patterns, collection locations and environmental conditions and the establishment of the conservation condition for the collections’ glasses. Lastly, an analytical approach was taken. Glass surface measurements indicate the alkalinisation of the glasses, as a sign of active corrosion. Through the use of in situ p-XRF analyses, glass chemical composition groups are correspondent with soda-lime-silicate glasses. Samples of aqueous chemical solutions were also collected and analysed through ICP-AES and HPIC with the goal to determine if the chemicals matched the containers’ labels and if they may present glass dissolution products. One of the outcomes of this dissertation is the development of preservation guidelines, through the empirical and analytical data gathered from the study of the MUHNAC’s collection, as well as the results of a survey addressed to similar institutions holding historical collections of chemicals. The final result is the proposal of guidelines that outline selection criteria for chemicals, tools and measures for collections’ care to objects and actions for collections’ keepers. It is intended that these guidelines may aid small and large institutions in the preservation of their collections.