Journal articles: 'Peroxide value'

1

Dutka, Volodymyr, and Nataliya Oshchapovska. "Adsorption of Oligomeric Peroxides on Aerosil and Magnesium Oxide and Their Behavior on the Water-Air Phases Interface." Chemistry & Chemical Technology 15, no. 1 (February 15, 2021): 47–52. http://dx.doi.org/10.23939/chcht15.01.047.

Full text

Abstract:

Oligomeric peroxide adsorption of sebacic acid on aerosil and magnesium oxide was studied. Adsorption process parameters were found. It is shown that the adsorption takes place through the hydrogen bonds formation between OH– groups of adsorbents surface and peroxide groups. The adsorption process suggests the behavior of peroxide compounds on the water-air phase’s interface. Monomolecular film formations on water surface for oligomeric peroxides were studied. It was found that calculated values of the area extrapolated to zero pressure (S0) depend on the solvent which was used to apply the peroxide in the phases interface. Oligomeric peroxide monolayers considered as condensation-type monolayers. Thermal decomposition of oligomeric peroxide and its di- and monoperoxide analogues was studied. It was shown that total constants of thermal degradation rate k for oligomeric peroxide are higher than those for di- and monoperoxide analogues. There is a correlation between S0 calculated values and the constants of thermal degradation rate for oligoperoxide. The less is S0 value the higher is k value. The conformational state of the macromolecule was preserved during transferring the oligomeric peroxide solution in an organic solvent to the phases interface that affects k values.

APA, Harvard, Vancouver, ISO, and other styles

2

Zhang, Haodong, Liu Bin, Longlong Lin, Rongxian Qu, Chen Wang, and Junmei Zhang. "Experimental study on lowering oleic acid value and peroxide value of camellia sinensis by scraping film molecular distillation." E3S Web of Conferences 251 (2021): 02029. http://dx.doi.org/10.1051/e3sconf/202125102029.

Full text

Abstract:

Camellia oil is a kind of natural product with high added value. In the process of production, processing, and transportation, acidic substances and peroxides that reduce the quality of oil are produced. In this paper, it was refined by scraping membrane molecular distillation device. The factors affecting the molecular distillation results were analyzed and studied through a single factor experiment and orthogonal experiment. On the surface of the experiment, the optimal process parameters were as follows: the temperature was 190℃, the pressure was 1 Pa, the scraping speed was 300r/min, and the feed amount was 900g/h. Under this condition, the acid value in camellia oil decreased from 2.67mgKOH/g to 0.19mgKOH/g, and the free fatty acid removal rate was 92.88%. The peroxide value decreased from 16.78mmol/kg to 1.03mmol/kg, and the peroxide removal rate was 93.86%. The experimental results showed that the surface of the scraping membrane molecular distillation equipment could meet the national standard of acid value and peroxide value under the appropriate technological parameters, and there was no solvent residue, which was a safe physical purification process.

APA, Harvard, Vancouver, ISO, and other styles

3

Laelia, Rahma, and Pramudya Kurnia. "The effect of frying frequency on acid value and peroxides in various types of oil." Ilmu Gizi Indonesia 3, no. 1 (August 28, 2019): 23. http://dx.doi.org/10.35842/ilgi.v3i1.119.

Full text

Abstract:

Background: People often store frying oil that will be reused or used repeatedly for several times, especially in salted fish frying. Cooking oil that has been used repeatedly with high temperatures or contact with water and oxygen will produce acid and peroxide values. This is due to the oxidation and hydrolysis processes causing oil damage. Objective: To identify the effect of frying frequency on the acid and peroxides value in various types of oil. Methods: This research was an experiment with salted fish frying based on a completely randomized design using three treatments (first, second, and the third frying processed) with three different types of oil, that were coconut oil, palm oil, and corn oil. Acids and peroxides values were analyzed using One Way Anova test continued with Duncan Multiple Range Test (DMRT) test. Results: Acid value in the three types of oil was still within the limits of the standards value 0.6 mg KOH/g based on SNI 3741: 2013 and free fatty acid 0.3% based on SNI 7709:2012. After first until third frying, peroxide value of coconut oil was still within the standard limit, whereas in palm oil and corn oil, after second frying were exceeded of the standard limit based on SNI which have maximal value 10 mek O2/kg. Conclusion: Frying frequency were affected by acid and peroxides values of coconut oil, palm oil, as well as corn oil.

APA, Harvard, Vancouver, ISO, and other styles

4

Shang, Xiaolan, Jie Qiao, and Zhanxiong Chen. "Changes in Lipase and Antioxidant Enzyme Activities during Processing of Cantonese Sausage with D-Sodium Erythorbate." Journal of Food Quality 2019 (August 1, 2019): 1–8. http://dx.doi.org/10.1155/2019/1671603.

Full text

Abstract:

Pork was used as raw material to produce Cantonese sausage, with additions of 0.05% or 0.1% D-sodium erythorbate. The oxidation indices (peroxide value, TBARS value, carbonyl value, and conjugated dienes value) and enzyme activity (total phospholipase, acid lipase, neutral lipase, superoxide dismutase, and glutathione peroxidase) were measured in the sausages at different processing periods. The results showed slowed lipid oxidation in the presence of D-sodium erythorbate, inhibition of total phospholipase, acid lipase, and neutral lipase activities, and increased superoxide dismutase activity, with little change in glutathione peroxidase activities. When increasing D-sodium erythorbate, the superoxide dismutase activity was negatively correlated with the peroxide value at 5 h (P<0.01), the neutral lipase activity was positively correlated with the conjugated dienes value at 15 h (P<0.01), and the total phospholipase activity was positively correlated with the peroxide value at 30 h (P<0.01). This study explored the antioxidant effect of D-sodium erythorbate and provides a theoretical foundation to improve the quality of Cantonese sausage.

APA, Harvard, Vancouver, ISO, and other styles

5

HARA, Setsuko, Yoshiyuki KOHNO, Minoru AOYAMA, Shuichi ABE, Tsugio ISOBE, Motoko KAKUTA, Kenichi KURIYAMA, et al. "Determination of Peroxide Value by Potentiometry." Journal of Japan Oil Chemists' Society 46, no. 6 (1997): 671–82. http://dx.doi.org/10.5650/jos1996.46.671.

Full text

APA, Harvard, Vancouver, ISO, and other styles

6

Suratno, Suratno, and Ronny Victor Utomo. "Bilangan Peroksida pada Minyak Goreng Penjual Gorengan di Jalan Rajawali Kota Palangka Raya." Borneo Journal of Medical Laboratory Technology 1, no. 1 (January 2, 2019): 25–29. http://dx.doi.org/10.33084/bjmlt.v1i1.461.

Full text

Abstract:

A high peroxide value of used vegetable oil can lead to poisoning in the body and various diseases such as diarrhea, fat deposition in blood vessels, cancer and decrease of digestibility of fat and destruction of vitamin E. This study aims to determine the peroxide values in reused cooking oil on fried snack seller on Jalan Rajawali, Palangka Raya. A quantitative descriptive research design was used in this study. Random sampling technique was used to collect the sample � determination of peroxide value using iodometry method. Results show that based on quality requirements, from 14 cooking oil samples there were 78.6% of the samples comply with the peroxide value requirements and 21.4% of the samples did not comply with the peroxide value requirements. Samples which did not adhere to the peroxide value requirements are cooking oil that has been used for more than five repetitions.

APA, Harvard, Vancouver, ISO, and other styles

7

Rustiana, Tuti, and Dinar Rahayu. "VARIASI WAKTU KONTAK ARANG AKTIF UNTUK MENURUNKAN BILANGAN PEROKSIDA PADA MINYAK GORENG BEKAS PAKAI." Medical Technology and Public Health Journal 5, no. 1 (April 7, 2021): 104–10. http://dx.doi.org/10.33086/mtphj.v5i1.1470.

Full text

Abstract:

Vegetable oil in the cooking process usually is used multiple times to fry food. This process exposes the oil to heat and oxidation. The oil itself is lipid. Lipid is a triglyceride, which means three carboxylic acids are bonded to one molecule of glycerol to form of ester. Exposing triglyceride to heat and oxidation causes it to deteriorate and break into smaller molecules such as aldehyde, ketones, and hydrocarbons. This molecule causes rancidity. Rancidity can be measured in terms of the amount of hydroperoxide presents in oil in mEq of O2/Kg. The peroxides present oxidize the iodide to iodine and the iodine is then titrated to a colorimetric endpoint using sodium thiosulfate with starch as an indicator. The amount of iodine produced is directly proportional to the peroxide value. The research has been conducted to reduce the peroxide value of used cooking oil using adsorption. The adsorbent used here is activated charcoal with a concentration of 3% and particle size of 100 Mesh. Contact time with oil is varied, ranged from 30 to 90 minutes. Statistic treatment of t-student test is performed between peroxide value before and after treatment and it is found that the difference is significant. That means active charcoal can decrease peroxide value. One way of ANOVA test among contact times (30, 60, 90 minutes) proves there is no significant difference, leading to the conclusion that activated charcoal at 3% and particle size 100 Mesh can decrease the peroxide value of oil in only 30 minutes of contact time.

APA, Harvard, Vancouver, ISO, and other styles

8

Hong, Suk-Ju, Shin-Joung Rho, Ah-Yeong Lee, Heesoo Park, Jinshi Cui, Jongmin Park, Soon-Jung Hong, Yong-Ro Kim, and Ghiseok Kim. "Rancidity Estimation of Perilla Seed Oil by Using Near-Infrared Spectroscopy and Multivariate Analysis Techniques." Journal of Spectroscopy 2017 (2017): 1–10. http://dx.doi.org/10.1155/2017/1082612.

Full text

Abstract:

Near-infrared spectroscopy and multivariate analysis techniques were employed to nondestructively evaluate the rancidity of perilla seed oil by developing prediction models for the acid and peroxide values. The acid, peroxide value, and transmittance spectra of perilla seed oil stored in two different environments for 96 and 144 h were obtained and used to develop prediction models for different storage conditions and time periods. Preprocessing methods were applied to the transmittance spectra of perilla seed oil, and multivariate analysis techniques, such as principal component regression (PCR), partial least squares regression (PLSR), and artificial neural network (ANN) modeling, were employed to develop the models. Titration analysis shows that the free fatty acids in an oil oxidation process were more affected by relative humidity than temperature, whereas peroxides in an oil oxidation process were more significantly affected by temperature than relative humidity for the two different environments in this study. Also, the prediction results of ANN models for both acid and peroxide values were the highest among the developed models. These results suggest that the proposed near-infrared spectroscopy technique with multivariate analysis can be used for the nondestructive evaluation of the rancidity of perilla seed oil, especially the acid and peroxide values.

APA, Harvard, Vancouver, ISO, and other styles

9

Tarchoune, Imen, Cristina Sgherri, Jamel Eddouzi, Angela Zinnai, Mike Quartacci, and Mokhtar Zarrouk. "Olive Leaf Addition Increases Olive Oil Nutraceutical Properties." Molecules 24, no. 3 (February 2, 2019): 545. http://dx.doi.org/10.3390/molecules24030545.

Full text

Abstract:

The aim of the present research was to study the effects of olive leaf addition (0 and 3%) on the major antioxidants and the antioxidant activity of Neb Jmel and Oueslati olive oils. Olives and leaves of the two Tunisian varieties were harvested during the 2016/2017 crop season. Both leaves and oils were characterised for their concentrations in phenolics, tocopherols and antioxidant power. Other parameters such as free acidity, peroxide value, chlorophyll and carotenoid concentrations were also taken into consideration. Compared to Oueslati, the Neb Jmel oil showed a lower free acidity (50%) and peroxide value (5.6-fold), and higher chlorophyll (1.6-fold), total phenolics (1.3-fold), flavonoid (3-fold) and oleuropein derivative (1.5-fold) concentrations, in addition to an increased antioxidant activity (1.6-fold). Leaf addition promoted a significant increment in total chlorophyll, α-tocopherol and phenolics in both varieties, above all in Oueslati oil, due to a higher abundance of bioactive constituents in the corresponding leaves. In particular, chlorophyll and carotenoid concentrations reached values twice higher than in Neb Jmel leaves, and flavonoids and oleouperin derivatives were three-fold higher. This prevented the oxidation and the formation of peroxides, reducing the peroxide value of the fortified oil to the half. The results provide evidence on the performance of the Tunisian Neb Jmel and Oueslati varieties, showing that their oils present a chemical profile corresponding to the extra virgin olive oil category and that, after leaf addition, their nutritional value was improved.

APA, Harvard, Vancouver, ISO, and other styles

10

Minami, Ichiro, Hisakazu Mori, Akihisa Katoh, Yoshio Marukane, and Yasushi Kohzu. "Proposal of Lubricant Maintenance by Monitoring Peroxide Value." Journal of the Japan Petroleum Institute 52, no. 6 (2009): 351–56. http://dx.doi.org/10.1627/jpi.52.351.

Full text

APA, Harvard, Vancouver, ISO, and other styles

11

STEPANYAN, V., A. ARNOUS, C. PETRAKIS, P. KEFALAS, and A. CALOKERINOS. "Chemiluminescent evaluation of peroxide value in olive oil." Talanta 65, no. 4 (February 28, 2005): 1056–58. http://dx.doi.org/10.1016/j.talanta.2004.08.041.

Full text

APA, Harvard, Vancouver, ISO, and other styles

12

Luo, Chuan, Beilei Wu, Zhenxin Lin, Lifeng Yuan, and Hao Wang. "Determination of Peroxide Value in the Plastic Resin." Asian Journal of Chemistry 25, no. 8 (2013): 4506–8. http://dx.doi.org/10.14233/ajchem.2013.14035.

Full text

APA, Harvard, Vancouver, ISO, and other styles

13

Mahoney, E. Y., M. Milewska, I. Mironczuk-Chodakowska, and K. M. Terlikowska. "The influence of carotenoid and chlorophyll content on the oxidative processes in the selected vegetable oils." Progress in Health Sciences 8, no. 2 (December 31, 2018): 144–51. http://dx.doi.org/10.5604/01.3001.0012.8337.

Full text

Abstract:

Purpose: More than 100 plant species have been classified as oil products, but only a few of them are used in industrial production. In the available literature, there are no studies that would describe the relationship between the content of plant dyes and their impact on auto-oxidative processes. Therefore, this study aimed to determine dye composition and to define their effect on the acid value, peroxide value and quality assessment of selected refined and unrefined oils. Materials and methods: Twenty samples from different manufacturers were evaluated. Oils were purchased from retail trade of the Bialystok city. The total colour, acid, and peroxide values were determined in accordance with the Polish Standards PN-ISO 3960: 1996, PN-A-86934: 1995 and PN-ISO 3960: 1996, respectively. Results: Statistically significant differences of total colour values between both groups were found (p=0.002). The acid value of refined oils was lower than in an unrefined group (p=0.02). A positive statistically significant correlation was noticed between the total colour value and the acid value in the refined group (R=0.65, p=0.04). No significant effect of plant dyes on the acid or peroxide value of unrefined oils was observed. Conclusions: Refined and unrefined oils purchased in the city of Bialystok mostly met the standard values with the exception of cold-pressed oil from black cumin seeds, where the acid and peroxide value exceeded the values set in Codex Alimentarius.

APA, Harvard, Vancouver, ISO, and other styles

14

Ugbeni, C. O., D. O. Idiakheua, and U. O. Ejovwokoghene. "BIOCHEMICAL CHANGES IN BEEF PATTIES BOILED WITH ETHANOL EXTRACT OF THE ROOT OF Glycyrrhiza glabra LINN." FUDMA JOURNAL OF SCIENCES 5, no. 1 (June 26, 2021): 202–9. http://dx.doi.org/10.33003/fjs-2021-0501-557.

Full text

Abstract:

The use of spices in boiling of meat is a common phenomenon. The root of Glycyrrhiza glabra is used locally as spice for met. This work was design to determine the effect of ethanol extract of Glycyrrhiza glabra on malondialdehyde content, percentage Metmyoglobin content, acid value, Heme-iron content and peroxide value of beef stored at 4oc for a storage time of 0 to 18 hours was evaluated. Samples were taken at interval of 6 hours for analysis of the biochemical parameters under study. The statistical difference observed in Acid value, Malondialdehyde content, Heme iron content and peroxide value showed no significant difference, all having P≥0.05 in beef treated with ethanol extract of Glycyrrhiza glabra when compared to the control. On the other hand, the statistical difference in percentage metmyoglobin content when compared to the control at 0 hour interval was significant having P≤0.05, then at other distinct time interval showed no significant difference having P≥0.05. Thus, this study revealed that the extract of Glycyrrhiza glabra have a decreased antioxidant property against rancidity in beef samples and peroxide formation, although the stability of antioxidant, antimicrobial properties of Glycyrrhiza glabra decreases with storage time resulting in the variation of percentage Metmyoglobin values, Malondialdehyde values and Heme iron values, Acid value and peroxide value of beef, which indicates it may not be a good spice for beef

APA, Harvard, Vancouver, ISO, and other styles

15

Wang, He Teng. "Research on the Kinetics Model of Hazel Nut Quality." Applied Mechanics and Materials 200 (October 2012): 550–53. http://dx.doi.org/10.4028/www.scientific.net/amm.200.550.

Full text

Abstract:

The time-course of lipid oxidation determined by peroxide value and acid value of hazel nut packed at different temperatures were evaluated, and the separate kinetic models of peroxide value and acid value with respect to storage time at different storage temperatures were established based on Arrhenius equation, so as to predict and control the quality of hazel nut during storage. The result show that the peroxide value and acid value of hazelnut increased with the storage time prolonged, besides, it will increase rapidly with the storage temperature increased. The Acid value and peroxide value has a high fitting precision with the chemical reaction model and the Arrhenius equation.

APA, Harvard, Vancouver, ISO, and other styles

16

Hao, Ke Fei, Mei Mei Hao, Lan Chen, Dong Wu, Chang Hong Song, Juan Juan Li, and Qi Li. "The Study of Stability of Processing Grease Storage Temperature on Soybean." Advanced Materials Research 912-914 (April 2014): 2014–17. http://dx.doi.org/10.4028/www.scientific.net/amr.912-914.2014.

Full text

Abstract:

This paper studied the soybean under different temperature storage processing stability of greaseComparison of the moisture content, oil acid value and peroxide value under - 10 °C 0 °C and room temperature storage stored two years in soybean production fat The results show that,The higher the temperature the lower stability of greaseThe higher the temperature, the lower stability of moisture contentUnder - 10 °C, water content change is only 0.04%. at Room temperature the moisture content changes 0.11%The higher the temperature, the soybean processing oil acid value, peroxide value, the greater the increaseunder - 10 °CAcid value increased by 0.07KOH/(mg/g), under room temperature the acid value increases 0.97 KOH/(mg/g)Under - 10 °C peroxide value change tendency for 0.6 mmol/kg, room temperature peroxide value change tendency for 3.9 mmol/kgTherefore, low temperature could delay the deterioration of quality of soybean, and further improve the variation of water content, and delayed the acid value and peroxide value increase.

APA, Harvard, Vancouver, ISO, and other styles

17

Kumar Baral, Prodip, Md Aqib Hossain Khan, Md Prince Mahmud, and Sakina Sultana. "Approaches Undertaken for Betterment of Stability and Acceptability of Cooking Soybean Oil." Indian Journal of Nutrition and Dietetics 54, no. 4 (October 12, 2017): 427. http://dx.doi.org/10.21048/ijnd.2017.54.4.15929.

Full text

Abstract:

In the present study storage conditions ensuring better stability of Soybean oil over a period of 180 days were investigated. The study was carried out on 12 samples (4x3) of three brands namely brand A, B and C. After periodic interval of time ‘acid value’ and ‘peroxide value’ for each sample were determined. The result showed that in every case, darkness decreased degradation in oil over the normal condition over the period of experiments. Results were expressed in terms of acid value and peroxide value. For example peroxide values for samples of brand A stored under normal condition and in the dark were 0.88 on first day where the value came up to 128.64 and 33.3 at the end of 180 days respectively. The trend remained the same for the samples of brand B and brand C. In this study an attempt was made to decrease autooxidation in oils when vitamin E was added (1 ml of 200IU d-α-tocopherol per 100 ml of oil). Samples with and without vitamin E were stored under normal condition and in the dark. Results were expressed in terms of peroxide values. Results failed to show a clear trend of decreasing auto oxidation at the end of 180 days irrespective of the nature of storing condition.

APA, Harvard, Vancouver, ISO, and other styles

18

Shantha, Nalur C., and Eric A. Decker. "Rapid, Sensitive, Iron-Based Spectrophotometric Methods for Determination of Peroxide Values of Food Lipids." Journal of AOAC INTERNATIONAL 77, no. 2 (March 1, 1994): 421–24. http://dx.doi.org/10.1093/jaoac/77.2.421.

Full text

Abstract:

Abstract The official International Dairy Federation method for determination of the peroxide value of anhydrous milk fat was extended to poultry, meat, fish, and vegetable oils. The ferrous oxidation–xylenol orange method for determination of peroxide values of liposomes and lipoproteins was modified to make it simpler and more rapid. These 2 spectro-photometric methods were used successfully to determine the peroxide values of beef, chicken, butter, fish, and vegetable products. The results in most cases were consistent with those obtained by using the AOAC Official Method. The spectro-photometric methods have an assay time of less than 10 min, require ≤0.3 g fat, and are capable of determining peroxide values as low as 0.1 mequiv/kg of sample.

APA, Harvard, Vancouver, ISO, and other styles

19

Kartikorini, Nastiti. "Efektivitas Vitamin C Pada Daun Kelor Terhadap Bilangan Peroksida Dari Minyak Jelantah." JOURNAL OF MUHAMMADIYAH MEDICAL LABORATORY TECHNOLOGIST 2, no. 2 (October 3, 2019): 28. http://dx.doi.org/10.30651/jmlt.v2i2.3380.

Full text

Abstract:

Used cooking oil is a cooking oil that has been used several times. Used cooking oil undergoes an oxidation reaction to produce high peroxide compounds. Phenolic compounds are primary antioxidants contained in Moringa leaves which slow the oxidation down in used cooking oil so that it can be stored longer. Formulation of the problem in this study was whether there was an inhibitory test on Moringa oleifera Leaves powder on the peroxide value in used cooking oil. The purpose of this study was to determine the inhibition of Moringa leaves powder to peroxide value on used cooking oil. This type of research was an experimental i.e. to determine whether there was the inhibition of Moringa leaves powder to the peroxide value in used cooking oil. The sample in this study was 5 samples from 6 fried traders, and repeated 5 times so that the total sample was 25 samples. Peroxide levels could be decreased due to the antioxidant content found in Moringa leaves. Antioxidants found in Moringa leaves are phenolic components. Phenolic components can inhibit free radicals and inhibit peroxide value to decrease. Moringa was suitable for areas where strong and long winds, drought occur simultaneously, and cause serious soil erosion. Nutrient content in deciduous leaves could fertilize and improve marginal soil quality (Dudi, 2015). Therefore, Moringa leaves not only have high antioxidants but also could be found easily in Surabaya. From the results of peroxide levels test, it was known that the average peroxide value in used cooking oil without Moringa leaves was equal to 23,9957 mEq and with Moringa leaves by different time variation i.e. 1 day (14,3182 mEq), 2 days (10,7987 mEq), 3 days (6,1593 mEq), 4 days (3,0397 mEq). Statistical analysis with Anova test showed the inhibition of Moringa leaves powder to decrease in peroxide value on used cooking oil with a value of p (sig) = 0,000 which was less than 0.05. Based on the results of the Tukey HSD test, the most effective soaking of Moringa leaves powder for 4 days was to reduce peroxide levels in used cooking oil by giving 5gr Moringa leaf powder with 100ml used cooking oil. Keywords : Levels of Peroxide Value, Moringa Leaves, Used Cooking Oil

APA, Harvard, Vancouver, ISO, and other styles

20

Dobriyan, E. I. "Dairy antioxidant system." Proceedings of the Voronezh State University of Engineering Technologies 82, no. 2 (September 18, 2020): 101–6. http://dx.doi.org/10.20914/2310-1202-2020-2-101-106.

Full text

Abstract:

A review of dairy antioxidants was done based on local and international sources. Oxidative processes of fat are the main cause of chemical spoilage of milk and dairy products. Lipid oxidation is associated mainly with the amount of unsaturated fatty acids in the shells of fat globules and plasma phospholipids, as well as with the amount of free fat. The products of oxidative reactions at different stages of lipid oxidation with atmospheric oxygen are fatty acid hydroperoxides, peroxides, aldehydes, ketones, hydroxy acidswhich not only worsen the organoleptic characteristics of milk, but some of them are toxic substances. The antioxidant ability of milk is due to vitamins A, C, E, carotenoids, enzymes, lactoferin, sulfur-containing amino acids. One of the most powerful natural antioxidants is ascorbic acid, which is able to absorb superoxide anion radicals, alkoxyl radicals, superoxide, iron oxide, nitric oxide. Group E vitaminsare described, being the primary fat-soluble antioxidants. Among this group of substances, the most biologically active form is ?-tocopherol. The contribution of carotenoids to antioxidant protection has been determined. Beta carotene is considered as a preventive antioxidant, as it can block singlet oxygen which ishighly toxic. The mechanisms of antioxidant action of various enzymes are disclosed. Xanthioxidase has been shown to oxidize various aldigides and purine bases to the corresponding acids. Lactoperoxidase catalyzes the oxidation of thiocyanate with hydrogen peroxide to form thiociagen. Catalase oxidizes hydrogen peroxide to form water and molecular oxygen. Glutathione peroxidase is capable of rapidly removing hydrogen peroxide and other peroxides. The mechanism of the antioxidant action of lactoferrin is described which is based on iron the chelation by it. The functions of sulfur-containing amino acids due to the binding of free radicals are disclosed. Determining the total antioxidant activity can be a biomarker of its biological value, which will allow to choose the most perspective areas of milk processing..

APA, Harvard, Vancouver, ISO, and other styles

21

Liang, Pengjuan, Chaoyin Chen, Shenglan Zhao, Feng Ge, Diqiu Liu, Binqiu Liu, Qimeng Fan, Benyong Han, and Xianfeng Xiong. "Application of Fourier Transform Infrared Spectroscopy for the Oxidation and Peroxide Value Evaluation in Virgin Walnut Oil." Journal of Spectroscopy 2013 (2013): 1–5. http://dx.doi.org/10.1155/2013/138728.

Full text

Abstract:

Recent developments in Fourier transform infrared spectroscopy-partial least squares (FTIR-PLSs) extend the application of this strategy to the field of the edible oils and fats research. In this work, FT-IR spectroscopy was used as an effective analytical tool to determine the peroxide value of virgin walnut oil (VWO) samples undergone during heating. The spectra were recorded from a film of pure oil between two disks of KBr for each sample at frequency regions of 4000–650 cm−1. Changes in the values of the frequency of most of the bands of the spectra were observed and used to build the calibration model. PLS model correlates the actual and FT-IR estimated value of peroxide value with a correlation coefficient of 0.99, and the root mean square error of the calibration (RMSEC) value is 0.4838. The methodology has potential as a fast and accurate way for the quantification of peroxide value of the edible oils.

APA, Harvard, Vancouver, ISO, and other styles

22

Syafrudin, Intan Permata Sari, Asterina Asterina, and Russilawati Russilawati. "Kandungan Bilangan Peroksida Minyak Goreng Pedagang di Jalan Perintis Kemerdekaan Kota Padang." Jurnal Ilmu Kesehatan Indonesia 1, no. 3 (May 24, 2021): 364–70. http://dx.doi.org/10.25077/jikesi.v1i3.86.

Full text

Abstract:

Background. Indonesian usually using repeatedly cooking oil for deep frying process. The repeated use of cooking oil can be found among street vendors. Consumption of repeatedly cooking oil could lead to hepatic disorder, cardiovasular disorder and even cancer. Objective. The research aims to describe and analyze peroxide value in cooking oil used by street vendors in Perintis Kemerdekaan street in Padang City. Methods. This is a descriptive research. The reseacrh objects were taken by purposive sample method and 23 samples cooking oil used by traders. This research was conducted at Clinical Laboratory of West Sumatera from October 2019 to May 2020. Results. This research found out 14 from 23 of cooking oil used by street vendors have peroxide value above the Indonesian National Standard (abbreviated SNI) 01-3741-2013. Cooking oil used by fritter street vendors have average peroxide value is 15.10 mEq O2/kg while pecel catfish and chicken street vendors is 10.29 mEq O2/kg. The avarage peroxide value in each type of cooking oil are bulk 10,81 mEq O2/kg, branded 14,64 mEq O2/kg and mixture 16,28 mEq O2/kg. Conclusion. More than half of the samples tested had exceed the maximum peroxide values (> 10 mEq O2/kg) and the highest average are found in fritter street vendor and mixture of bulk and branded cooking oil.

APA, Harvard, Vancouver, ISO, and other styles

23

HARA, Setsuko, Katsuhiko SHIMIZU, and Yoichiro TOTANI. "Potentiometric Determination of Low Peroxide Value of Lipids. VI." Journal of Japan Oil Chemists' Society 37, no. 12 (1988): 1153–57. http://dx.doi.org/10.5650/jos1956.37.1153.

Full text

APA, Harvard, Vancouver, ISO, and other styles

24

HARA, Setsuko, Masaki SHIDA, and Yoichiro TOTANI. "Poteritiometric Determination of Low Peroxide Value of Lipids. IV." Journal of Japan Oil Chemists' Society 37, no. 2 (1988): 119–23. http://dx.doi.org/10.5650/jos1956.37.119.

Full text

APA, Harvard, Vancouver, ISO, and other styles

25

HARA, Setsuko, Masaki SIDA, and Yoichiro TOTANI. "Potentiometric Determination of Low Peroxide Value of Lipids. V." Journal of Japan Oil Chemists' Society 37, no. 6 (1988): 427–30. http://dx.doi.org/10.5650/jos1956.37.427.

Full text

APA, Harvard, Vancouver, ISO, and other styles

26

HARA, Setsuko, Yoko KURODA, Shinsuke NAKAGAWA, and Yoichiro TOTANI. "Modified Potentiometric Method with Isooctane for Peroxide Value Determination." Journal of Japan Oil Chemists' Society 43, no. 1 (1994): 18–22. http://dx.doi.org/10.5650/jos1956.43.18.

Full text

APA, Harvard, Vancouver, ISO, and other styles

27

TAKESHITA, Yasuhiko, Satoshi YONEYAMA, Satoshi TANABE, Shigehisa MIKI, Akiko ARAKAWA, Kazuo IIMURA, Tatsuo SHIKAMA, et al. "Determination of Peroxide Value by Acetic Acid-Isooctane Method." Journal of Japan Oil Chemists' Society 43, no. 7 (1994): 586–93. http://dx.doi.org/10.5650/jos1956.43.586.

Full text

APA, Harvard, Vancouver, ISO, and other styles

28

Mortensen, Grith, John Sørensen, and Henrik Stapelfeldt. "Comparison of Peroxide Value Methods Used for Semihard Cheeses." Journal of Agricultural and Food Chemistry 50, no. 18 (August 2002): 5007–11. http://dx.doi.org/10.1021/jf0200220.

Full text

APA, Harvard, Vancouver, ISO, and other styles

29

Yadav, R. S. S., K. S. Yadav, and H. S. Yadav. "Luffa aegyptiaca (Gourd) Fruit Juice as a Source of Peroxidase." Enzyme Research 2011 (July 24, 2011): 1–5. http://dx.doi.org/10.4061/2011/319105.

Full text

Abstract:

Peroxidases have turned out to be potential biocatalyst for a variety of organic reactions. The research work reported in this communication was done with the objective of finding a convenient rich source of peroxidase which could be used as a biocatalyst for organic synthetic reactions. The studies made have shown that Luffa aegyptiaca (gourd) fruit juice contains peroxidase activity of the order of 180 enzyme unit/mL. The Km values of this peroxidase for the substrates guaiacol and hydrogen peroxide were 2.0 and 0.2 mM, respectively. The pH and temperature optima were 6.5 and 60°C, respectively. Like other peroxidases, it followed double displacement type mechanism. Sodium azide inhibited the enzyme competitively with Ki value of 3.35 mM.

APA, Harvard, Vancouver, ISO, and other styles

30

Sunmonu, M. O., E. O. Ajala, M. M. Odewole, S. Morrison, and A. M. Alabi. "Comparative Analysis of Physico-Chemical Properties of Oil Extract From Two Varieties of Fluted Pumpkin Seeds Using Different Extraction Methods." Kathmandu University Journal of Science, Engineering and Technology 13, no. 2 (October 8, 2018): 48–60. http://dx.doi.org/10.3126/kuset.v13i2.21283.

Full text

Abstract:

This study investigates physical and chemical properties two seeds namely Ugba (Telfairia pedata) and Ugwu (Telfairia occidentalis) using soaking soxhlet methods of extraction. The physical properties examined are moisture content, ash content, crude protein, fat and oil, crude fibre and carbohydrates. The chemical properties examined are Acid value (mgKOH/g), saponification value, iodine value, free fatty acid, peroxide and refractive index. Higher mean values of moisture content, ash content, crude fibre and carbohydrates were noticed in Ugwu than in Ugba under soaking method. However, the trend was reversed for crude protein and free fatty acid, in whose case they appear to be higher in Ugba than in Ugwu. For soxhlet method, moisture content, ash content, crude fibre and carbohydrates seems to have higher mean values in Ugwu seed compared to when Ugba seed was used. However, crude protein and fat and oil content were higher using Ugba seed than Ugwu seed oil. For soaking method, Ugba seed seem to produce higher mean values of sap value, iodine value, and refractive index when compared with Ugwu seed. On the other Ugwu, seems to produce acid value, free fatty acid and peroxide value when compared with ugba for soaking method. Using soxhlet apparatus however, Ugba seed produces higher mean values for acid value, sap value, iodine value, and free fatty acid compared to Ugwu. The reverse was the case with peroxide and refractive index, still with soxhlet apparatus.Kathmandu University Journal of Science, Engineering and TechnologyVol. 13, No. 2, 2017, page: 48-60

APA, Harvard, Vancouver, ISO, and other styles

31

Marto, Carlos Miguel, Mafalda Laranjo, Anabela Paula, Ana Sofia Coelho, Ana Margarida Abrantes, João Casalta-Lopes, Ana Cristina Gonçalves, et al. "Cytotoxic Effects of Zoom® Whitening Product in Human Fibroblasts." Materials 13, no. 7 (March 25, 2020): 1491. http://dx.doi.org/10.3390/ma13071491.

Full text

Abstract:

Tooth whitening procedures are increasing; however, side effects can occur, such as damage to pulp cells, by the whitening products. This study aims to assess the cellular effects promoted by a whitening product, namely, the oxidative stress fostered by the active agent hydrogen peroxide, with and without photoactivation. Additionally, if cellular recovery occurred, we intended to determine the time point where cells recover from the tooth whitening induced damage. Human fibroblasts were exposed to hydrogen peroxide, Zoom®, Zoom® + irradiation, and irradiation alone. The following analysis was performed: metabolic activity evaluation by the MTT assay; cell viability, mitochondrial membrane potential, peroxides production, superoxide radical production, and reduced glutathione expression by flow cytometry. We determined the IC50 value for all groups, and a dose-dependent cytotoxic effect was verified. At the times analyzed, hydrogen peroxide groups showed no metabolic activity recovery while a cell recovery was observed after 24 h (Zoom®) and 48 h (Zoom® + irradiation). Cell death was seen in hydrogen peroxide and Zoom® + irradiation groups, mainly by apoptosis, and the irradiation had a cytotoxic effect per se. This in vitro study supports that whitening products with moderate hydrogen peroxide (HP) concentration have a temporary effect on cells, allowing a cellular recovery.

APA, Harvard, Vancouver, ISO, and other styles

32

Saeed, R., and S. Naz. "Effect of heating on the oxidative stability of corn oil and soybean oil." Grasas y Aceites 70, no. 2 (February 14, 2019): 303. http://dx.doi.org/10.3989/gya.0698181.

Full text

Abstract:

The effects of conventional and microwave heating on the oxidative properties of corn and soybean oil were evaluated. The results showed that acid value, peroxide value, oxidative indices, total oxidation value, and p-anisidine values changed significantly with the rise in temperature (p < 0.05). The peroxide and p-anisidine values for corn oil (PV: 50.670 meqO2/kg, p-AV: 8.248) were greater than soybean oil (PV: 41.694 meqO2/kg, p-AV: 7.566) for conventional heating. The peroxide and p-anisidine values for soybean oil (PV: 6.545 meqO2/kg, p-AV: 76.539) were greater compared to corn oil (PV: 5.074 meqO2/kg, p-AV: 65.360) for microwave heating. The results concluded that microwave heating had a greater impact on the chemical degradation of the fatty acids of the oil. The FT-IR spectra showed peak changes at 3743 cm-1 and 1739 cm-1 and confirmed the rancidity of the oils from microwave heating due to the formation of secondary oxidation products. It was concluded that corn oil showed more oxidative changes compared to soybean oil.

APA, Harvard, Vancouver, ISO, and other styles

33

Gonçalves, Maria Fernanda Donato, and Sueli Regina Baggio. "Evaluation of quality of butter from different provenance." Food Science and Technology 32, no. 3 (August 14, 2012): 629–35. http://dx.doi.org/10.1590/s0101-20612012005000091.

Full text

Abstract:

Butter samples were evaluated for free fatty acids, peroxide value, cholesterol, and fatty acid composition focusing on the trans isomer and conjugated linoleic acid (CLA). Sixty six samples were analyzed. Thirty six were collected in Brazil, eighteen in France, and twelve in Argentina. Samples were evaluated by free fatty acids, peroxide value, total lipid, cholesterol and fatty acid composition. The free fatty acid content varied from 0.16 to 0.46 g.100 g-1 and the peroxides value levels from 0.35 to 1.80 meq.kg-1. The cholesterol content varied from 192.8 to 226.3 g.100 g-1 and the total lipid content varied from 81.8 to 86.8 g.100 g-1. The levels of saturated, monounsaturated, and polyunsaturated fatty acids varied from 43.86 to 52.74, from 21.65 to 23.34, and from 2.11 to 2.89 g.100 g-1, respectively. The conjugated linoleic acid (CLA) content varied from 0.56 to 0.86 g.100 g-1 and the levels of total trans isomer varied from 2.18 to 3.81 g.100 g-1.

APA, Harvard, Vancouver, ISO, and other styles

34

Ha, Jaeho, Minseon Koo, and Hyunee Ok. "Determination of the Constituents of Sesame Oil by near Infrared Spectroscopy." Journal of Near Infrared Spectroscopy 6, A (January 1998): A371—A373. http://dx.doi.org/10.1255/jnirs.227.

Full text

Abstract:

The important factors of sesame oil on its quality are acid value, peroxide value, and fatty acid composition. Acid value and peroxide value are determined by a wet analysis and fatty acid compositions by a gas chromatographic method. This study was carried out to ascertain the potential for utilizing NIR spectrophotometry as a means of rapid and non-destructive method to determine the constituent of sesame oil. Using both a fixed type and a grating-type device, the calibration obtained from the samples of sesame oil was successfully applied to the determination of the constituents such as acid value, peroxide value and fatty acids.

APA, Harvard, Vancouver, ISO, and other styles

35

Cayuela, José A. "Assessing olive oil peroxide value by NIRS, and on reference methods." NIR news 28, no. 3 (April 30, 2017): 12–16. http://dx.doi.org/10.1177/0960336017703238.

Full text

Abstract:

Peroxide value is a basic parameter used for the olive oil quality characterization. We report trials to establish an NIR or Vis/IR spectroscopy technique to allow the satisfactory determination of the olive oil peroxide value. In relation to this, the possibility is considered if the NIR technique can offer greater accuracy and precision than the reference method. The NIR or Vis/NIR technique would avoid the large consumption of reagents and solvents needed in the usual method, also facilitating a faster and potentially multi-parametric measurement.

APA, Harvard, Vancouver, ISO, and other styles

36

Lehukov, Konstantin A., and Sergei S. Tsikin. "A STUDY ON AN EFFECT OF THE GREEN TEA EXTRACT ON QUALITY AND SHELF LIFE OF ANIMAL FATS DURING STORAGE." Theory and practice of meat processing 5, no. 1 (April 16, 2020): 32–42. http://dx.doi.org/10.21323/2414-438x-2020-5-1-32-42.

Full text

Abstract:

An analysis of an effect of the green tea extract on quality and shelf life of animal fats is presented. It is shown that the rate and depth of fat hydrolysis depend on a storage temperature. The higher the storage temperature, the higher the rate of fat hydrolysis and, consequently, the acid value. During storage for more than 3 days at any temperature, fats (except mutton fat) begin to change their properties. Mutton fat shows the first signs of spoilage (an increase in the acid value of more than 2.2 mg КОН, MAC ND) after 10 days of storage. An insignificant variation in the peroxide value of all tested fats during 10 days of storage, which was within the range of MAC, was established. After 10 days of storage, the rate of formation of peroxides and hydroperoxides rose sharply, which was confirmed by the peroxide value of these fats. Addition of antioxidants of the green tea extract in an amount of 10 g per 100 kg fat ensured appropriate storage of all fat types upon storage conditions that corresponded to the normative and technical documentation.

APA, Harvard, Vancouver, ISO, and other styles

37

Seweh, Emmanuel Amomba, Zou Xiaobo, Feng Tao, Shi Jiachen, Haroon Elrasheid Tahir, and Muhammad Arslan. "Multivariate analysis of three chemometric algorithms on rapid prediction of some important quality parameters of crude shea butter using Fourier transform-near infrared spectroscopy." Journal of Near Infrared Spectroscopy 27, no. 3 (February 20, 2019): 220–31. http://dx.doi.org/10.1177/0967033519830061.

Full text

Abstract:

A comparative study of three chemometric algorithms combined with NIR spectroscopy with the aim of determining the best performing algorithm for quantitative prediction of iodine value, saponification value, free fatty acids content, and peroxide values of unrefined shea butter. Multivariate calibrations were developed for each parameter using supervised partial least squares, interval partial least squares, and genetic-algorithm partial least square regression methods to establish a linear relationship between standard reference and the Fourier transformed-near infrared predicted. Results showed that genetic-algorithm partial least square models were superior in predicting iodine value and saponification value while partial least squares was excellent in predicting free fatty acids content and peroxide values. The nine-factor genetic-algorithm partial least square iodine value calibration model for predicting iodine value yielded excellent ( R2 cal = 0.97), ( R2 val = 0.97), low (root mean square error of cross-validation = 0.26), low (root mean square error of Prediction = 0.23), and (ratio of performance to deviation = 6.41); for saponification value, the nine-factor genetic-algorithm partial least square saponification value calibration model had excellent R2 cal (0.97), R2 val (0.99); low root mean square error of cross-validation (0.73), low root mean square error of Prediction (0.53), and (ratio of performance to deviation = 8.27); while for free fatty acids, the 11-factor partial least square free fatty acids produced very high R2 cal (0.97) and R2 val (0.97) with very low root mean square error of cross-validation (0.03), low root mean square error of Prediction (0.04) and (ratio of performance to deviation = 5.30) and finally for peroxide values, the 11-factor partial least square peroxide values calibration model obtained excellent R2 cal (0.96) and R2val (0.98) with low root mean square error of cross-validation (0.05), low root mean square error of Prediction (0.04), and (ratio of performance to deviation = 5.86). The built models were accurate and robust and can be reliably applied in developing a handheld quality detection device for screening, quality control checks, and prediction of shea butter quality on-site.

APA, Harvard, Vancouver, ISO, and other styles

38

PELIN, George, Cornel STOICA, Cristina Elisabeta PELIN, and Raluca BALASA. "High concentration hydrogen peroxide for rocket fuel applications." INCAS BULLETIN 12, no. 3 (September 1, 2020): 151–57. http://dx.doi.org/10.13111/2066-8201.2020.12.3.12.

Full text

Abstract:

This paper presents the experimental study of the distillation of hydrogen peroxide to increase the concentration of the solution, in order to use it as rocket fuel in space applications. The process of obtaining the desired concentration required for the operation of the wind tunnel model rocket engine was obtained using the vacuum distillation method. The process consists in removing a calculated value of the water content from the hydrogen peroxide solution with a concentration of 35%, thus increasing its concentration up to the value of 90%. The key factors that contribute in obtaining the desired concentration were evaluated and experimental results were compared with the calculated values.

APA, Harvard, Vancouver, ISO, and other styles

39

LEVRI, ELVIO A., LUCIA PATRASCU, and WILLIAM J. KELCH. "Peroxide Stability in Shortening: A Useful Reference Material." Journal of Food Protection 54, no. 11 (November 1, 1991): 897–99. http://dx.doi.org/10.4315/0362-028x-54.11.897.

Full text

Abstract:

Vegetable shortening was studied to determine if its peroxide value was stable enough after storage for one year to be used as a quality control reference material. Shortening samples were deliberately oxidized to contain low, medium, and high levels of peroxide and were then stored at 4°C for one year. Peroxide value was measured approximately every 14 d during this year. A total of 27 different determinations was made at each of the three different peroxide levels. The results indicated minimum variability within each level of peroxide during the year, and suggested that shortening would serve well as a reference material for quality control in the fats and oils industry and in food and nutrition research.

APA, Harvard, Vancouver, ISO, and other styles

40

Odiko, A. E., and E. Joseph. "Effect of storage periods and packaging materials on the proximate and chemical properties of frozen blue whiting (Micromesistius poutassou) at different exposure time." Journal of Applied and Natural Science 9, no. 3 (September 1, 2017): 1881–93. http://dx.doi.org/10.31018/jans.v9i3.1457.

Full text

Abstract:

This research seeks to determine the effect of storage periods and packaging materials on the proximate and chemical properties of frozen blue whiting (Micromesistius poutassou) at different exposure time – 0 hour, 2 hours and 4 hours, on arrival at the laboratory. Frozen M. poutassou were bought and stored in a commercial cold room for 12 weeks at -10oC and packed in different packaging materials (Ziploc bag, foil paper and carton) with un-wrapped samples for analysis which lasted 90 days and was conducted every 14 days to measure the moisture, protein, fat, ash, fibre and nitrogen free extract (NFA) content of the fish sample as well as iodine value, peroxide value, saponification value, acid value, free fatty acid and hydroxyl value of fish oil. The result clearly reveals that during storage, the different packaging materials showed significantly (p<0.05) decreasing trend in protein, lipid, ash, fibre and NFA content with increasing storage period and time of analysis except for the moisture content that showed opposite trend. For the chemical properties, the saponification value, peroxide value, free fatty acid, acid value and hydroxyl value showed significantly (p<0.05) increasing trend in the different packaging materials with increasing storage period and time of analysis. While the iodine value decreased with increasing period of storage and time of analysis; the iodine, saponification, peroxide and hydroxyl values were not within the acceptable limits.

APA, Harvard, Vancouver, ISO, and other styles

41

Sabolová, Monika, Václav Zeman, Gabriela Lebedová, Marek Doležal, Josef Soukup, and Zuzana Réblová. "Relationship between the fat and oil composition and their initial oxidation rate during storage." Czech Journal of Food Sciences 38, No. 6 (December 23, 2020): 404–9. http://dx.doi.org/10.17221/207/2020-cjfs.

Full text

Abstract:

Until now, the relationship between the fat and oil composition and their oxidation stability has been studied only at elevated temperatures (typically above 100 °C). Therefore, the initial oxidation rates of 19 edible fats and oils were determined as an increase in the peroxide value during storage in the dark at 35 °C with free access to air (oxygen). The initial oxidation rates of fats and oils were compared with parameters characterising these fats and oils (peroxide value, acid value, fatty acid composition, antioxidant capacity, and tocochromanol content). Using a simple correlation analysis, the initial oxidation rate correlated the most strongly with the peroxide value of the analysed fats and oils (P < 0.01). A highly reliable model (P < 0.0001) was obtained by multivariate statistical analysis. According to this model, the initial oxidation rate is affected mainly by the peroxide value and then by total trans fatty acid content, and antioxidant capacity.

APA, Harvard, Vancouver, ISO, and other styles

42

Islami, Nadya, Debby Saputera, and Rahmad Arifin. "THE SOAKING EFFECT OF 100% SMALL WHITE GINGER EXTRACT ON THE VALUE OF THE FLEXURAL STRENGTH OF ACRYLIC BASE (Flexural Strength Value of Acrylic Base Using Acrylic Resin Heat Cured Type)." Dentino : Jurnal Kedokteran Gigi 5, no. 1 (March 12, 2020): 10. http://dx.doi.org/10.20527/dentino.v5i1.8114.

Full text

Abstract:

Background: The denture base material that is widely used is heat cured acrylic resin. One of mechanical properties of acrylic resin that must be considered in the selection of the basic denture material is flexural strength. Flexural strength is needed, among others, to resist the chewing power that must be received by dentures. The commonly used denture cleanser is Alkaline peroxide. 100% small white ginger extract can be used as natural denture cleanser. Objective: This study aimed to compare the flexural strength of heat cured acrylic base which in soaked 100% small white ginger extract with Alkaline peroxide solution as artificial denture cleanser. Method: This study was a pure laboratory experimental study with post test only with control group design, using simple random sampling. The sample was rectangular with a size of 65x10x2,5 mm. The number of samples used was 24 heat cured resin acrylic which was divided into 3 immersion groups, 100% small ginger extract, Alkaline peroxide, and aquades. The immersion carried out for 3 days 19 hours 25 minutes, obtained from 5 minutes denture cleanser presentation every day for 3 years. Flexural strength was tested using a Universal Testing Machine 3 Point Bending. Result: The everage flexural strength value of heat cured acrylic resin after soaked in 100% small white ginger extract was 70,98, in Alkaline peroxide 87,37, and 91,05 in aquades. The data was annalyzed using parametric One Way ANOVA test and Post Hoc Bonferroni test. Conclusion: The flexural strength of heat cured acrylic resin that soaked in 100% small white ginger extract is smaller than Alkaline peroxide after immersed for 3 days 19 hours 25 minutes.

APA, Harvard, Vancouver, ISO, and other styles

43

Brzezińska, Rita, Agata Górska, Kinga Gotowicka, Joanna Bryś, Ewa Ostrowska-Ligęza, and Magdalena Wirkowska-Wojdyła. "Quality Assessment of Avocado Pulp Oils during Storage." Proceedings 70, no. 1 (November 9, 2020): 14. http://dx.doi.org/10.3390/foods_2020-07694.

Full text

Abstract:

Recently, consumers’ awareness is becoming a crucial aspect driving the food industry to develop new products with high nutritional value. The oil industry explores the use of less well-known plant materials such as avocado fruit which is a rich source of bioactive compounds. The objective of this study was to assess the quality and oxidative stability of avocado pulp oils during a 2-month storage period. Two avocado varieties, Hass and Reed, were selected and oil extraction was performed with the use of hexane. The extent of oxidative deterioration and oil stability were tested by measuring the acid value and peroxide value. The PDSC method was applied to evaluate the oxidative induction time. The composition of fatty acids and their distribution in internal (sn-2) and external (sn-1 and sn-3) positions in triacylglycerols were also analyzed. The acid value and the peroxide value of fresh extracted avocado oils reached approximately 0.6 mg KOH g−1 fat and 5 meq O2 kg−1 fat, respectively. Generally, during avocado oil storage both the acid values and the peroxide values were in accordance with Codex Alimentarius requirements (the limit for acid value is 4 mg KOH g−1, while for peroxide value it is 15 meq O2 kg−1). The Hass avocado pulp oil was characterized by a higher value of the oxidative induction time, about 111 min, compared to the oil extracted from Reed avocado pulp (61 min). The GC analysis revealed that avocado pulp oil could be considered a source of monounsaturated fatty acids. The dominant fatty acid found in this group was oleic acid with a percentage share of above 60%. In accordance with the results of fatty acids distribution in triacylglycerol molecules, the main fatty acids in the sn-2 position were linoleic acid and oleic acid and their percentage share in this item was up to 59% and 34%, respectively. It was also noticed that after a 2-month storage period, the acid value and the peroxide value increased about 7-fold and 2-fold, the oxidative induction time decreased about 2-fold and the percentage shares of fatty acid groups changed. In conclusion, the results obtained in this research indicate that storage period has a significant impact on avocado pulp oil quality.

APA, Harvard, Vancouver, ISO, and other styles

44

Zeleňáková, Lucia, Mária Angelovičová, Marek Šnirc, Jana Žiarovská, Stanislav Kráčmar, Branislav Gálik, and Simona Kunová. "Thermo-degradative changes of rapeseed and sunflower oils during deep-frying French fries." Potravinarstvo Slovak Journal of Food Sciences 13, no. 1 (February 27, 2019): 138–49. http://dx.doi.org/10.5219/1080.

Full text

Abstract:

The purpose of this study was to investigate changes in TPCs, acid value and peroxide value as well as fatty acids composition in edible oils during french fries production. Lower TPCs content was found in rapeseed oil (3.3%) and the threshold (24%) was achieved on the fourth day. The total time for the deterioration of deep-frying rapeseed oil was 23½ hours. On the contrary, in fresh sunflower oil at the first day was TPCs content 5.5% and the limit of 24% was reached on the third day. The total time for the deterioration of deep-frying sunflower oil was 17½ hours. The results indicated significant differences (<0.05) in TPCs content between rapeseed and sunflower oils during deep-frying process. At the beginning of deep-frying French fries in rapeseed oil, the acid number was 0.374 mg KOH.g-1 and 1.271 mg KOH.g-1 at the fourth day of deep-frying. The measured peroxide value was 4.3 mEq O2.kg-1 at the beginning and at the end of deep-frying 10.5 mEq O2.kg-1. The initial peroxide and acid values were higher in sunflower oil compared with rapeseed oil, respectively. It should be note, then the acid values and peroxide values, respectively, in the two fresh oils used in this study were below the limit of refined oil according to Slovak legislation (peroxide value - not more than 10 mEq O2.kg-1, acid value - not more than 0.6 mg KOH.g-1). However, detected values varied during deep-frying process. Monounsaturated fatty acids were predominantly observed in fresh rapeseed oil (61.22%) wherever in sunflower oil they were much lower (29.77%). A slight increase of MUFA was found in both oils. The initial content of saturated fatty acids in rapeseed oil was 6.94%, in fresh sunflower oil was observed slightly higher content of SFA (10.37%). The major groups of fatty acids in fresh sunflower oil were polyunsaturated fatty acids (PUFA) which have in principle a significant effect on oil deterioration. A slight decrease of PUFA was observed in both oils throughout the frying period. The content of PUFA was reduced by about 9.42% in rapeseed oil and by 10.8% in sunflower oil. The initial content was 28.14% and 58.91%, respectively.

APA, Harvard, Vancouver, ISO, and other styles

45

Lachman, Jaromír, Alena Hejtmánková, Zora Kotíková, Martin Dědina, Radomíra Střalková, and Vladimír Hönig. "Stability of Grape Seed Oil and its Antioxidant Tocotrienols." Advanced Materials Research 1030-1032 (September 2014): 370–73. http://dx.doi.org/10.4028/www.scientific.net/amr.1030-1032.370.

Full text

Abstract:

For the experiment three different storage conditions were chosen: storage at room temperature of 22 °C in the light and in the dark and in the dark in a refrigerator at 4 °C. Parameters monitored were: peroxide value and changes in the content of α-, γ-and δ-tocotrienols and α - and γ-tocopherols during storage for 210 days (30 weeks). The peroxide value is an indicator of the content of primary oxidation products of oils. From analytical analyses results that the greatest destruction of grape oil occurs during storage at room temperature and access of light, where a peroxide value increased up to 484 meq. O2/kg oil). The least intrusive method of storage was in terms of temperature refrigerator (4 °C) in the dark, when during 30 days of storage peroxide value had risen only to 71.9 meq. O2/kg oil. Between these values were values stored at room temperature in the dark (after 30 weeks storage 196 meq. O2/kg oil). From these parameters is clearly showed that to the stability of oil contribute significantly both factors - temperature and light conditions. The same trend was also found in tocotrienols. At room temperature and access of light was complete decomposition of α-tocotrienol in the 9th week of storage, γ-tocotrienol at 30 weeks of storage and δ-tocotrienol in the 18th week of storage. The most stable seems γ-tocotrienol > δ-tocotrienol > α-tocotrienol. When stored in the refrigerator in the dark, there was practically no decomposition of α-, γ-and δ-tocotrienols whose contents remained completely unchanged.

APA, Harvard, Vancouver, ISO, and other styles

46

&NA;. "Benzoyl peroxide best value for acne in UK community setting." Inpharma Weekly &NA;, no. 1470 (January 2005): 4. http://dx.doi.org/10.2165/00128413-200514700-00008.

Full text

APA, Harvard, Vancouver, ISO, and other styles

47

van de Voort, F. R., A. A. Ismail, J. Sedman, J. Dubois, and T. Nicodemo. "The determination of peroxide value by fourier transform infrared spectroscopy." Journal of the American Oil Chemists' Society 71, no. 9 (September 1994): 921–26. http://dx.doi.org/10.1007/bf02542254.

Full text

APA, Harvard, Vancouver, ISO, and other styles

48

Li, Hui, F. R. van de Voort, A. A. Ismail, and R. Cox. "Determination of peroxide value by fourier transform near-infrared spectroscopy." Journal of the American Oil Chemists' Society 77, no. 2 (February 2000): 137–42. http://dx.doi.org/10.1007/s11746-000-0023-7.

Full text

APA, Harvard, Vancouver, ISO, and other styles

49

Magalhães, K. T., T. S. Tavares, T. M. C. Gomes, and C. A. Nunes. "Multi-target response surface optimization of the aqueous extraction of Macauba kernel oil." Grasas y Aceites 71, no. 4 (December 30, 2020): 377. http://dx.doi.org/10.3989/gya.0788191.

Full text

Abstract:

Macauba (Acrocomia aculeata) is a promising tropical palm for the production of vegetable oil for both the food and non-food sectors. In this work, a multi-target response surface optimization of the aqueous extraction of Macauba kernel oil aimed to maximize the oil yield and minimize the free acidy and peroxide value. High yield was achieved at a high pH, long extraction periods and moderate temperatures, but these conditions contributed to elevating the peroxide value of the oil. On the other hand, pH presented the only significant effect on the oil’s acidity, which decreased with the increase in pH in the aqueous medium. Therefore, the multi-target response surface optimization based on a desirability approach showed that pH 11, room temperature (25 °C) and a 60 min agitation time was preferred to obtain high yield and low free acidity and peroxide values. These conditions resulted in 30% yield (63.1% of the yield obtained by solvent extraction), 0.3% free acidity, and a peroxide value of 2.9 meqO2/kg. The oil from the optimized aqueous extraction had a higher saturated fatty acid content compared to that from solvent extraction, especially fatty acids with < 14 carbon atoms, which can make the oil harder and more useful for producing special fats for specific food applications.

APA, Harvard, Vancouver, ISO, and other styles

50

Ma, Yanping, Chaoye Wang, Chaobin Liu, Jiawei Tan, Huiling Ma, and Jin Wang. "Physiochemical Responses of the Kernel Quality, Total Phenols and Antioxidant Enzymes of Walnut in Different Forms to the Low-Temperature Storage." Foods 10, no. 9 (August 28, 2021): 2027. http://dx.doi.org/10.3390/foods10092027.

Full text

Abstract:

Fresh walnut is obtaining high attention due to its pleasant taste and health benefits. This study aimed to evaluate the influence of storage temperatures (0 °C and −20 °C) on the kernel quality, total phenols, and antioxidant enzyme activities of walnuts in three forms (fresh kernels, walnuts with green husk, and walnuts with shell). For a short storage within 3 months at 0 °C, the results revealed that walnuts with green husk provided a better walnut kernel quality resulting from its lower acid value and peroxide value, together with a higher total phenol content and total antioxidant activity, compared with other forms of walnuts. In comparison, frozen storage at −20 °C for a long duration (up to 10 months), found that walnuts with shell showed advantages in improving the kernel quality (fatty acid content, total phenols, and total antioxidant activity) and antioxidant enzyme (peroxidase, catalase, and superoxide dismutase) activities in the kernels, leading to an acceptable range of acid value and peroxide value, compared with other forms of walnuts. Thus, frozen storage at −20 °C showed a potential application in maintaining the walnut kernel quality, especially the walnuts with shell.

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Peroxide value'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles