Academic literature on the topic 'Antioxidant'
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Journal articles on the topic "Antioxidant"
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Gonokami, Mio, Yoshimasa Yamamoto, Oraphin Chaikumpollert, Yoshito Ohtake, and Seiichi Kawahara. "ANTIOXIDANTS FOR EPDM SEALS EXPOSED TO CHLORINATED TAP WATER." Rubber Chemistry and Technology 87, no. 1 (March 1, 2014): 1–9. http://dx.doi.org/10.5254/rct.13.87963.
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ABSTRACT A suitable antioxidant for a poly(ethylene-co-propylene-co-5-ethylidene-2-norbornene) (EPDM) seal in tap water applications was determined with respect to volatilization and decomposition of the antioxidants. Seals were prepared by mixing EPDM with 1 phr antioxidant and other ingredients followed by vulcanizing the mixture at 433 K for 20 min. The resulting EPDM seals were immersed into chlorinated water to investigate accelerated degradation. The change in antioxidant content was measured by gas chromatography/mass spectroscopy (GC/MS) and high-performance liquid chromatography (HPLC). The weight loss of amine antioxidants during vulcanization was quite low due to their low volatility and decomposition. Antioxidant weight loss during accelerated degradation depended on both the antioxidant's ability to trap radicals and solubility in chlorinated water.
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Buřičová, L., M. Andjelkovic, A. Čermáková, Z. Réblová, O. Jurček, E. Kolehmainen, R. Verhé, and F. Kvasnička. "Antioxidant capacity and antioxidants of strawberry, blackberry, and raspberry leaves." Czech Journal of Food Sciences 29, No. 2 (March 25, 2011): 181–89. http://dx.doi.org/10.17221/300/2010-cjfs.
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The total phenolic content (Folin-Ciocalteu method), free radical scavenging ability expressed as DPPH value, ferric reducing antioxidant capacity (FRAP), and oxygen radical absorbance capacity (ORAC) were determined in water extracts of leaves from Rosaceae family plants (Fragaria vesca L., Rubus fructicosus L., and Rubus idaeus L.). The antioxidant capacities of the extracts (in the order of the above mentioned methods) were 73.6–88.9%, 60.1–71.4%, 49.7–78.0% respectively, and 45.3–66.5% of that of green tea water extract. Further, the presence of 15 compounds (gallic acid, rutin, ellagic acid, caffeic acid, p-coumaric acid, quercetin, kaempferol, myricetin, quercetin-3-d-glucoside, ascorbic acid, (+)-catechin, (–)-epicatechin, epicatechingallate, epigallocatechin, procyanidin B1) was studied by HPLC-ECD and their antioxidant capacities were compared to the antioxidant capacity of the extracts. Out of the compounds studied, mostly (+)-catechin, ellagic acid, and (–)-epicatechin participated in the antioxidant capacities of the studied plant leaves water extracts. The antioxidant capacity of leaves infusions (determined by DPPH method) was lower than those of red wines and tea infusions, but comparable to the antioxidant capacities of white wines and fruit beverages.
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Shoker, Roaa M. H., Wasan Hamza Al-Shammery, and S. R. Al-Aidy. "A Review Article: Free Radical and Replacement Synthetic Antioxidant by Natural Antioxidant." Journal for Research in Applied Sciences and Biotechnology 2, no. 2 (May 11, 2023): 206–11. http://dx.doi.org/10.55544/jrasb.2.2.29.
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Free radical may be responsible of several pathophysiology disease for threatening human life, and they are produced from endogenous and exogenous sources. Using the balanced amount of nutritious diet lead to a good health, may be neutralizing or scavenging free radicals by antioxidants compounds. daily diet have large number of vitamin A, E and C, carotenoids, polyphenols, etc. as natural antioxidants, the main bases of them are fruits, cereals, vegetables, and beverages. Enzymatic and non-enzymatic antioxidant substances are two different kinds that lessen the reactions of free radicals. In order to protect itself from reactive oxygen species, the human body uses an enzyme antioxidant. The two kinds of non-enzymatic antioxidants are natural antioxidants and synthetic antioxidants. The aim of this review is to knowledge a reasons which causes the free radical and balance them by natural antioxidant constituents, and replacement synthetic antioxidant by natural antioxidant, due to daily diet have large amounts from natural antioxidants, and natural antioxidants more effective than synthetic antioxidants, in additional they occurrence in nature and more inexpensive.
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Smajić Bećić, Arnela, Ramzija Cvrk, Amela Kusur, Halid Junuzović, and Tijana Brčina. "Comparative analysis of the antioxidant capacity of some natural and synthetic antioxidants added to palm oil." Technologica acta 15, no. 2 (March 2023): 19–23. http://dx.doi.org/10.51558/2232-7568.2022.15.2.19.
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Various synthetic and natural antioxidants are used to reduce oxidation and its negative impact on the oil during the food frying process. Considering that some studies show the negative impact of synthetic antioxidants on the health of consumers, natural alternatives are being used more and more. BHA and BHT are synthetic antioxidants that are widely used in the food industryand a large number of natural compounds such as phenols, anthocyanins, flavonoids, vitamins, etc. show antioxidant properties. In this study, the antioxidant capacity of oregano and rosemary essential oil was tested and compared with the antioxidant capacity of BHA and BHT. The antioxidant capacity was evaluated by the removal of DPPH radicals and by iron reduction (FRAP). The results of this study showed that the studied essential oils exhibited antioxidant capacity. These oils have a high antioxidant capacity, however, compared to synthetic antioxidants, they show a significantly lower antioxidant capacity but they can be used as natural antioxidants during food processing. KEYWORDS:antioxidant capacity; essential oils; synthetic antioxidants; lipidoxidation
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Sadowska-Bartosz, Izabela, and Grzegorz Bartosz. "Effect of Antioxidants Supplementation on Aging and Longevity." BioMed Research International 2014 (2014): 1–17. http://dx.doi.org/10.1155/2014/404680.
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If aging is due to or contributed by free radical reactions, as postulated by the free radical theory of aging, lifespan of organisms should be extended by administration of exogenous antioxidants. This paper reviews data on model organisms concerning the effects of exogenous antioxidants (antioxidant vitamins, lipoic acid, coenzyme Q, melatonin, resveratrol, curcumin, other polyphenols, and synthetic antioxidants including antioxidant nanoparticles) on the lifespan of model organisms. Mechanisms of effects of antioxidants, often due to indirect antioxidant action or to action not related to the antioxidant properties of the compounds administered, are discussed. The legitimacy of antioxidant supplementation in human is considered.
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Pan, F. G., E. Q. Yang, J. Y. Xu, Y. F. Lu, C. X. Yang, Y. D. Zhang, S. Li, and B. Q. Liu. "Review on preparation methods, mechanisms and applications for antioxidant peptides in oil." Grasas y Aceites 73, no. 4 (December 15, 2022): e478. http://dx.doi.org/10.3989/gya.0560211.
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Natural antioxidants, especially those used in edible oil, are safer compared to chemically synthesized antioxidants. Therefore, research on natural antioxidants has become prevelant. Antioxidant peptides derived from food protein can effectively prevent oil oxidation. Protein hydrolyzation is widely applied for the production of antioxidant peptides in industry, and bioinformatics is employed nowadays to generate the desired peptide sequence. Furthermore, the mechanism of antioxidant peptides in the oil system is still controversial, which limits the further development of antioxidant peptides as food antioxidants. This review introduces the preparation method of antioxidant peptides and their mechanisms as well as applications in the oil. It will help to comprehensively understand the function of antioxidant peptides and promote their development in the oil field.
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Pastor, Rosario, and Josep A. Tur. "Antioxidant Supplementation and Adaptive Response to Training: A Systematic Review." Current Pharmaceutical Design 25, no. 16 (August 23, 2019): 1889–912. http://dx.doi.org/10.2174/1381612825666190701164923.
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Background: Antioxidant supplementation has become a common practice among athletes to theoretically achieve a reduction in oxidative stress, promote recovery and improve performance. Objective: To assess the effect of antioxidant supplements on exercise. Methods: A systematic literature search was performed up to January 2019 in MEDLINE via EBSCO and Pubmed, and in Web of Sciences based on the following terms: “antioxidants” [Major] AND “exercise” AND “adaptation”; “antioxidant supplement” AND “(exercise or physical activity)” AND “(adaptation or adjustment)” [MesH]. Thirty-six articles were finally included. Results: Exhaustive exercise induces an antioxidant response in neutrophils through an increase in antioxidant enzymes, and antioxidant low-level supplementation does not block this adaptive cellular response. Supplementation with antioxidants appears to decrease oxidative damage blocking cell-signaling pathways associated with muscle hypertrophy. However, upregulation of endogenous antioxidant enzymes after resistance training is blocked by exogenous antioxidant supplementation. Supplementation with antioxidants does not affect the performance improvement induced by resistance exercise. The effects of antioxidant supplementation on physical performance and redox status may vary depending on baseline levels. Conclusion: The antioxidant response to exercise has two components: At the time of stress and adaptation through genetic modulation processes in front of persistent pro-oxidant situation. Acute administration of antioxidants immediately before or during an exercise session can have beneficial effects, such as a delay in the onset of fatigue and a reduction in the recovery period. Chronic administration of antioxidant supplements may impair exercise adaptations, and is only beneficial in subjects with low basal levels of antioxidants.
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Singh, Poornima, Virginia Paul, and Ritu Dubey. "Antioxidant Foods." International Journal of Advances in Agricultural Science and Technology 9, no. 4 (April 30, 2022): 1–7. http://dx.doi.org/10.47856/ijaast.2022.v09i04.001.
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Antioxidant is any substance that delays, prevents or removes oxidative damage to a target molecule. It can be found in many foods, including fruits and vegetables. The role of antioxidants in foods is to retard or control oxidation. The process of autoxidation and development of rancidity in foods involves a free radical chain mechanism via initiation, propagation and termination steps. While radicals are produced in the ‘initiation’ step, they react with unsaturated fatty acids by abstracting a hydrogen atom from a site which requires the least energy that is the allylic or diallylic position in the ‘propagation’ steps. The reactions in the propagation step make up a chain reaction until a ‘termination’ reaction occurs. Due to high stability and low volatility, it helps to maintain the level of nutrients, the texture, colour, taste, freshness, functionality, aroma, and appeal to consumers such as the older person. Various antioxidants found in food viz. natural antioxidants, synthetic antioxidants, dietary antioxidant, endogenous antioxidant play an important role in preservation of food. Vitamin C, Vitamin E, α-carotene, Lycopene, Polyphenol etc. is main sources of antioxidants The benefits of antioxidants include whole foods and beverages (e.g., acai berry, gogi berry, green tea) as well as isolated substances sold primarily as dietary supplements (e.g., vitamin C, lycopene, selenium) or added to foods (e.g., vitamin E). It reduces the risk of developing certain diseases such as; cancer, heart disease, stroke, and arthritis etc.
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Butterfield, D. Allan, and Jeffrey N. Keller. "Antioxidants and antioxidant treatment in disease." Biochimica et Biophysica Acta (BBA) - Molecular Basis of Disease 1822, no. 5 (May 2012): 615. http://dx.doi.org/10.1016/j.bbadis.2012.02.020.
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Pokorný, J., Š. Schmidt, and H. T T Nguyen. "Functionality changes of natural antioxidants during food processing and storage." Czech Journal of Food Sciences 22, SI - Chem. Reactions in Foods V (January 1, 2004): S80—S83. http://dx.doi.org/10.17221/10617-cjfs.
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Food raw materials and products contain inhibitors of oxidation reactions, both in the lipidic phase and the aqueous phase. The most important inhibitors are phenolic antioxidants. During food processing and storage, concentrations of antioxidants in the two phases reach an equilibrium. Phenolics react with lipidic free radicals, being converted into antioxidant free radicals, quinones, polymers and copolymers. Some degradation products possess an antioxidant activity, too. The relative antioxidant activity decreases with decreasing concentration of oxygen in the system and with increasing temperature. Antioxidants are more rapidly decomposed in surface layers. Health aspects of antioxidant degradation products are often neglected as the safety of antioxidant degradation products is mostly unknown.
Dissertations / Theses on the topic "Antioxidant"
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Macuchová, Simona. "Studium aktivity enzymových a nízkomolekulárních antioxidačních systémů." Doctoral thesis, Vysoké učení technické v Brně. Fakulta chemická, 2010. http://www.nusl.cz/ntk/nusl-233305.
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Oxidative processes play important role in cell physiology and pathology as well. Balance of these processes is supplied by cooperating antioxidative systems; function of antioxidant defense systems depens on high levels of antioxidants in organism. Presented work is focused on developement and optimization of methods for analysis of important enzyme and non-enzyme antioxidants as well as total antioxidant capacity of selected types of biological material. Extractions and analyses of vitamin E, carotenoids, superoxide dismutase, catalase, peroxidase and lipoxygenase in barley and malt were optimized. RP-HPLC and HPLC/ESI-MS were used for analysis of vitamin E, phenolic and carotenoid content, spectrophotometry was used for enzymes activity analysis. A new methods for catalase and lipoxygenase activities were developed and compared with direct UV methods. Superoxide dismutase activity was determined by commercial diagnostic kit. A colorimetric method was used for peroxidase activity determination. Some kinetic parameters of enzymes were provided too. Optimized methods were used in the analyses of antioxidants in plant material - in barley and malt - in sets of samples of 6 varieties cultivated in four different locations for two years. Content of individual antioxidants differed depending on the variety, but usually were not found significant differences in the levels, depending on growing location. Perhaps climatic conditions have the greatest influence on levels of low molecular weight and enzymatic antioxidants at the specific location; oxidation processes are influenced both the quantity of moisture, both by sunlight, which induces oxidative processes in cultivated plants. The activity of antioxidants in barley caryopses is rapidly increasing during the malting process; an elevated temperature and moistness first induces activation the enzyme systems including antioxidant. In caryopsis is metabolic activity increased during which we can expect an increased production of radicals; for this purpose can antioxidant systems be activated that protect cells from damage by oxidative stress. In the second part of work optimized methods were applied in two clinical trials focused on study of the influence of exogenous antioxidants intake on metabolic and antioxidant status in human organism. In the first clinical study influence of food supplement containing polyunsaturated fatty acids and vitamin E on metabolism of hyperlipidaemics was evaluated. After 3-month supplemenation a lipid profile was improved and serum antioxidant levels increased. The second experiment was focused on enzyme and non-enzyme antioxidant levels in healthy subjects after temporarily intake of specific foods rich in antioxidants. After two-month intake plasma phenolic substances were slightly increased. Total antioxidant capacity and activities of enzyme antioxidants were not affected. Results of both clinical exeriments showed that supplying of antioxidants in natural form or in the form of food supplements does not markedly affect metabolism of healthy subjects, while in patients with chronic diseases antioxidant supplementation can positively influence metabolic status. Results of this work showed that optimized methods are suitable for analyses of antioxidant status parameters and also for monitoring of exogenous antioxidant intake.
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Jardini, Fernanda Archilla. "Avaliação da atividade antioxidante da romã (Punica granatum, L.) - participação das frações de ácidos fenólicos no processo de inibição da oxidação." Universidade de São Paulo, 2005. http://www.teses.usp.br/teses/disponiveis/9/9131/tde-30062008-163119/.
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Os antioxidantes de origem natural têm importância na área de alimentos, pois podem representar uma alternativa de substituição aos antioxidantes sintéticos. Os compostos fenólicos, presentes nos vegetais, desempenham importância na inibição da oxidação, A romã (Punica granatum, L.) é rica em compostos fenólicos como as antocianinas, flavonóides e ácidos fenólicos. Avaliou-se a atividade antioxidante da polpa e semente de romãs plantadas no Brasil (Pernambuco), e foi feita a obtenção dos extratos e frações de ácidos fenólicos da fruta, que foram submetidos aos testes de co-oxidação de substratos β- caroteno e ácido linoléico, em meio emulsionado, e ao método Rancimat, em meio lipídico. Também foi avaliado o comportamento cinético da atividade antioxidante para os extratos e frações de ácidos fenólicos. Verificou-se que os extratos aquosos da polpa e semente apresentaram significativa inibição da oxidação a concentrações baixas, em ambos os testes utilizados, fato atribuído à grande quantidade de compostos fenólicos presentes nestes extratos, em relação aos demais. A avaliação cinética dos extratos aquosos demonstrou que estes também foram mais eficientes ao longo do processo oxidativo, apresentando-se mais estáveis do que o antioxidante sintético BHT. As frações de ácidos fenólicos esterificados a compostos solúveis da polpa foi a fração que apresentou maior inibição da oxidação, e também maior quantidade de compostos fenólicos, apresentando uma atividade cinética bastante eficiente. Entretanto, as frações de ácidos fenólicos livres da polpa e semente apresentaram porcentagens de inibição da oxidação bastante altas a uma concentração menor. A semente da romã apresenta em sua composição de ácidos graxos o ácido graxo punícico. Este ácido é um isômero conjugado do ácido linolênico, e que constitui 58% da composição total de ácidos graxos da semente da fruta, sendo seu principal ácido graxo.The antioxidants of natural origin have an important role on food science, because they may substitute the synthetic antioxidants. The phenolic compounds of vegetables play an important role as oxidation inhibitors. The pomegranate (Punica granatum, L.) is rich in phenolic compounds as anthocianins, flavonoids and phenolic acids. The antioxidant activity of extracts and acid phenolic fractions obtained from the pulp and seeds of brazilian pomegranate (from Pernambuco) was evaluated, by the co-oxidation of β-carotene and linoleic acid assay and the Rancimat method. The kinetic behavior of the antioxidant activity of the extracts and acid phenolic fractions by the co-oxidation of β-carotene and linoleic acid test was evaluated, too. It was noted that the aquous extracts from the pulp and seeds have significant antioxidant activity at slow concentration. It was possible by the high content of phenolic compounds present on those extracts. The kinetic behavior showed that the aquous extracts was the most efficient along the oxidative process, showing larger stability than the antioxidant BHT. The pulp\'s of bound acid phenolic fraction by soluble compounds was the most efficient among the acid phenolic fractions, and it has major amount of phenolic compounds. The pomegranate seed has the punicic acid on its fatty acid composition. The punicic acid is a I conjugated inolenic acid isomer.The punicic acid is present at 58% from the total fatty acids from the fruit, being its principal fatty acid.
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Barošová, Michaela. "Sledování antioxidantů v sušeném ovoci." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2008. http://www.nusl.cz/ntk/nusl-216231.
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Presented diploma work is focused on study of antioxidants in different kinds of dried fruits. Analyses of ascorbate, tocopherols, carotenoids and flavonoids were performed using RP-HPLC with spectrophotometric detection. Analysis of dried fruits showed high level of vitamins and phenolocs mainly in berries. High level of carotenoids was observed in dried apricots and plums. Further, antioxidant activity of dried fruit extracts was tested by ABTS method. High antioxidant activity was found mainly in dried apples, cranberries and blueberries. The biological test with yeast Sascharomyces cerevisiae D7 was used for the analysis of antimutagenic efects of dried fruits. High antimutagenic activity exhibited dried cranberries and blueberries. Most of tested dried fruits with high antimutagenic effect exhibited also high antioxidant activity as well as high content of some antioxidants. No direct correlation was found among these parameters. Last part of this work was focused on study of influence of drying on antioxidant content in two types of apples. Drying at mild controlled conditions exhibited no significant negative effect on active substance content; in some samples their concentration was observed.
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Ferdová, Jitka. "Změny aktivit enzymů v ovoci v průběhu dlouhodobého uchovávání." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2010. http://www.nusl.cz/ntk/nusl-216605.
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This study is focused on study of changes of enzyme and low-molecular weight antioxidants in different fruits during long-term storage. In theoretical part individual low-molecular weight antioxidants and enzymes are described. The main causes of fruit decay and some possibilities of fruit preservation and storage are summarized. As biological material some common fruits were chosen - green and red apples, peaches, plums and white grapes. The fruits were stored in laboratory, cellar, in refrigerator and in freezer. In freezing experiments some ways of fruit preparation and processing were tested and their influence on fruit antioxidant status was compared. Shortened storage experiment was applied on blueberries, cranberries, raspberries and strawberries too. In fruits some group parameters – total antioxidant status, dry mass content, ascorbate level, total flavonoids and total phenolics were analyzed spectrophotometrically. Individual flavonoids and phenolics were determined by RP-HPLC/UV-VIS and on-line LC/PDA/ESI-MS. Antioxidant enzyme activities (superoxide dismutase SOD, catalase CAT, polyphenol oxidase PPO and lipoxygenase LOX) were measured by spectrophotometry. The surface microscopy and cultivation of moulds from fruit surface were performed too. Influence of storage conditions on biological activities is dependent on fruit sort. Freezing is the most suitable procedure for long-term storage without significant changes of active substance content. Long-term storage in controlled temperature conditions and/or atmosphere is usable for fruits with longer storage period. In these fruits stabile levels of antioxidant enzymes are stored for relatively long time. Some of enzymes act synergistically. Enzyme activities differed according to storage phase; at the beginning mainly high SOD and LOX activities were observed. CAT and PPO are probably activated as defence systems in rippened and/or damaged fruits. Levels of total as well as individual low molecular weight antioxidants varied during storage in all sorts, generally, increased course with longer storage period can be observed.
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Alves, Adriana Barreto. "Compostos antioxidantes em polpa de tomate : efeito do processamento e da estocagem." [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/255267.
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Orientador: Neura BragagnoloTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
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Resumo: Estudos epidemiológicos têm demonstrado que o consumo de frutas e vegetais tem um efeito benéfico na redução da incidência de várias doenças como o câncer e doenças cardiovasculares. Esse efeito tem sido relacionado com a presença de compostos antioxidantes nesses alimentos, sobretudo os flavonóides. O tomate (Lycopersicum esculentum Mill.) é um dos vegetais mais consumidos no mundo, in natura ou processado, e também é rico em compostos antioxidantes como carotenóides, vitaminas e flavonóides. Os alimentos processados, frequentemente, são tidos como menos nutritivos que os alimentos in natura, devido, principalmente, ao fato de que alguns nutrientes são degradados pelas altas temperaturas empregadas. Assim, torna-se importante avaliar o efeito do processamento e da estocagem sobre os compostos antioxidantes do tomate e também sobre sua atividade antioxidante. Um planejamento experimental foi realizado para otimizar as condições de extração dos compostos fenólicos e concentração dos flavonóides em polpa de tomate concentrada. O método otimizado foi validado para as determinações de compostos fenólicos totais e flavonóides totais por espectrofotometria e também para a determinação de flavonóides por cromatografia líquida de alta eficiência (CLAE). Os métodos espectrofotométricos foram validados nos parâmetros repetibilidade e exatidão. A determinação de flavonóides por CLAE foi validada nos parâmetros seletividade, linearidade, precisão, exatidão e sensibilidade. O efeito do processamento e da estocagem sobre os compostos antioxidantes do tomate foi avaliado. Foram analisados os teores de compostos fenólicos totais, flavonóides totais, flavonóides por CLAE, ácido ascórbico, licopeno e ß-caroteno, bem como a atividade antioxidante das frações hidrofílicas e lipofílicas pelos métodos ABTS e DPPH. Verificou-se que, durante o processamento, em geral, não houve perdas dos compostos antioxidantes. Durante o armazenamento, observou-se grande degradação do ácido ascórbico, porém, os demais compostos mantiveram-se estáveis, e não foi observada nenhuma alteração na atividade antioxidante. O efeito do processamento sobre a atividade antioxidante do extrato fenólico foi também avaliado por espectroscopia de ressonância de elétron-spin (ESR) usando sal de Fremy e em sistema-modelo de lipossomas. Esses e os outros resultados de atividade antioxidante obtidos previamente foram correlacionados com os teores de compostos fenólicos totais a fim de melhor estudar os mecanismos de ação antioxidante envolvidos. A ação antioxidante das amostras de tomate, coletadas em diferentes etapas do processamento, foi testada em carne de frango processada sob alta pressão a 300, 600 e 800 MPa e armazenada sob refrigeração por 15 dias. A adição de 0,30% de subproduto (pele + semente) ou 0,10% de polpa concentrada resultou em uma fase lag de 6 dias para a formação de produtos secundários da oxidação lipídica na carne de frango processada a 600 MPa. O subproduto apresentou efeito similar também para a carne de frango processada a 800 MPa. O resultado deste trabalho mostrou que, embora o processamento e a estocagem de polpa de tomate possam ter degradado substâncias mais sensíveis como o ácido ascórbico, os demais compostos antioxidantes não sofreram alterações deletérias, e, para alguns, o processamento foi benéfico, aumentando sua disponibilidade. De forma semelhante, as atividades antioxidantes dos produtos processados foram iguais ou maiores que as das amostras in natura e se mantiveram estáveis durante o armazenamento por um ano. Além disso, o subproduto do processamento pode ter boas chances de aplicação como antioxidante em outros produtos alimentícios
Abstract: Epidemiological studies have shown that the consumption of fruits and vegetables has a beneficial effect on reducing some diseases like cancer and cardiovascular diseases. These benefits have been associated to the presence of antioxidant compounds in those foods, mainly flavonoids. Tomato (Lycopersicum esculentum Mill.) is one of the most worldwide consumed vegetables, in natura or processed. Moreover, tomato is rich in many antioxidant compounds like carotenoids, vitamins and flavonoids. Frequently, thermoprocessed foods are taken as less healthy than in natura foods, mainly because nutrient losses caused by high temperature. So, it is very important to evaluate the effect of processing and storage on tomato antioxidant compounds and on their antioxidant activity. A response surface methodology was used to optimize the phenolics extraction conditions and flavonoids concentration from concentrated tomato paste. The optimized method was validated for total phenolics and total flavonoids spectrophotometric determinations and also for flavonoids quantification by high performance liquid chromatography (HPLC). The spectrophotometric methods were validated for repeatability and recovery. Flavonoids determination by HPLC was validated for selectivity, linearity, precision, recovery and sensibility. Processing and storage effect on tomato antioxidant compounds was evaluated. Total phenolics, total flavonoids, flavonoids by HPLC, ascorbic acid, lycopene and ß-carotene were determined and also the antioxidant activity of hydrophilic and lipophilic fractions were studied using ABTS and DPPH methodologies. It was observed that during processing, in general, there was no loss of the antioxidant compounds present in tomato. During the storage time there was a great loss of ascorbic acid, but all other antioxidant compounds were stable and no changes in their antioxidant activity were observed. The effect of tomato paste processing on the antioxidant activity of phenolic extract was also analyzed through electron-spin resonance spectroscopy (ESR) using Fremy¿s salt, and in a liposome model-system. These and the other antioxidant activity results previously obtained were correlated with the total phenolics content found in the samples in order to better study the antioxidant mechanisms involved. The antioxidant action of tomato samples, collected at different processing steps, was analyzed during 15 days chill storage of high-pressure treated chicken meat balls at 300, 600, and 800 MPa. Addition of 0.30% tomato waste (skin + seeds) or of 0.10% final tomato paste to minced meat led to a lag phase of 6 days for formation of secondary oxidation products in meat treated at 600 MPa. The waste product seemed especially efficient in protecting chicken meat pressurized at 800 MPa, as a notably lower rate of formation of secondary oxidation products was found. This work showed that, although processing and storage of tomato paste might result in loss of the most labile substances like ascorbic acid, the other antioxidant compounds were not affected, and, for some of them, processing increased their availability. Similarly, the antioxidant activities of final products were equal to or greater than the in natura ones and remained unaltered during one year storage. In addition, waste material may have good chances of application as antioxidant in other foods
Doutorado
Ciência de Alimentos
Doutora em Ciência de Alimentos
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Pires, Manoela Alves. "Avaliação da capacidade antioxidante de extratos comerciais de alecrim e chá verde e sua influência na estabilidade de hambúrguer de frango durante armazenamento congelado." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/74/74132/tde-06102014-110832/.
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A atividade antioxidante de dois extratos comerciais de alecrim e chá verde foi comparada com a atividade do sintético BHA para substituição total do sintético em hambúrguer de frango. A quantificação foi determinada pelos métodos Folin-Ciocalteau, FRAP e DPPH. De acordo com as análises de atividade antioxidante, as dosagens dos extratos naturais foram determinadas, utilizando-se como base o limite de dosagem do BHA (0,01% base gordura) e aplicadas em hambúrgueres de frango: T1: Controle; T2: 0,002% BHA; T3: 0,0038% Chá Verde; T4: 0,001% Chá Verde; T5: 0,048% Alecrim; T6: 0,00186% Alecrim. Foram realizadas análises de composição centesimal e pH e análises de estabilidade no armazenamento congelado: rendimento e redução do diâmetro, índice de TBARs, cor objetiva (parâmetros L*, a* e b*) e teste sensorial de aceitação. No método Folin-Ciocalteau, das análises de atividade antioxidante, o BHA não apresentou diferença com o chá verde (p > 0,05), no método FRAP o melhor (p < 0,05) desempenho foi do BHA e no DPPH o chá verde apresentou maior atividade (p < 0,05). Os resultados de TBARS, nos hambúrgueres, mostraram diferença significativa entre as amostras e também interação amostras x tempo do armazenamento (p < 0,05), sendo que após 120 dias o teste com maior dosagem do extrato de alecrim (T5) não diferiu do sintético (T2) (0,423 e 0,369 índice de TBARs, respectivamente). No aspecto sensorial as amostras não diferiram entre si (p>0,05) nem durante todo o período de armazenamento (p > 0,05). Dentro das condições experimentais pode-se afirmar que o extrato comercial de alecrim pode substituir totalmente o antioxidante BHA em hambúrguer de frango, garantindo a mesma estabilidade oxidativa e sem interferir em sua aceitação sensorial.The antioxidant activity of two commercial extracts, rosemary and green tea, were compared with the activity of the synthetic BHA for total replacement of the synthetic in chicken burger. The spectrometric quantification was determined by UV - VIS methods: Folin - Ciocalteu , FRAP and DPPH . In the Folin-Ciocalteau method the BHA showed no difference with green tea (p > 0.05), in the FRAP method the BHA obtained better (p < 0.05) performance and for DPPH the green tea showed greater activity (p < 0.05). According to the analysis of antioxidant activity, dosages of natural extracts were determined, using as basis the limit dosage of BHA (0.01 % fat base) and applied in chicken burgers: T1: Control, T2: 0.002 % BHA, T3: 0.0038 % Green Tea, T4: 0.001 % Green Tea, T5: 0.048 % Rosemary and T6: 0.00186 % Rosemary. Chemical-physical analysis of chemical composition and pH were made, and also stability analysis: cooking loss and reducing the diameter, TBARs index, objective color (parameters L *, a * and b *) and sensory acceptance test. The results of TBARS showed a significant difference between samples and also samples interaction x storage time (p < 0.05), after 120 days the test with higher dosage of rosemary extract (T5) did not differ from synthetic (T2) (0.423 and 0.369 TBARS index, respectively), thus better performance than the other tests. The sensory evaluation results showed that the samples did not differ during the storage period (p > 0.05). According the experimental conditions can be concluded that the commercial rosemary extract can completely replace the antioxidant BHA.
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Vicente, Silvio José Valadão. "Caracterização antioxidante do café (Coffea arabica, L.) e efeitos da sua administração oral em ratos." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/6/6133/tde-10092009-092017/.
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Introdução: Um dos fatores de risco para doenças crônicas não-transmissíveis é o excesso de espécies reativas causado pelo estresse oxidativo. Ácidos fenólicos atuam na defesa contra estas espécies, agindo como antioxidantes e como fatores de transcrição para as enzimas antioxidantes fase II (superóxido dismutase, catalase e glutationa peroxidase). Vários alimentos possuem ácidos fenólicos na composição porém o café se destaca pelo alto conteúdo dos mesmos e por ser consumido mundialmente. Objetivos: a) Comparar a capacidade antioxidante e a estabilidade dos cafés regular e descafeinado ao longo de seis meses; b) Verificar o tempo de resposta e possíveis correlações dose-resposta do efeito antioxidante em ratos após dose única de café; c) Avaliar o efeito antioxidante e possíveis danos hepáticos em ratos submetidos a doses repetidas de café durante 30 dias. Métodos: na etapa in vitro, foram analisados os compostos fenólicos totais, os principais ácidos fenólicos, a capacidade antioxidante (ORAC e DPPH) e a estabilidade destes parâmetros nos cafés regular e descafeinado durante seis meses. Na etapa in vivo, foram utilizados ratos machos Wistar, sendo dosadas as enzimas fase II e o ORAC, além do exame histopatológico e biomarcadores. Resultados: o café regular apresentou capacidade antioxidante inicial superior ao descafeinado com compostos fenólicos totais iguais e maiores teores de ácido fenólicos (15,3% cafêico, 17,0% p-cumárico e 38,1% ferúlico), ORAC (20,8%) e DPPH (3,9%). Após 6 meses, as amostras fechadas à vácuo praticamente não sofreram perdas, as abertas mantidas a 4oC apresentaram perdas medianas (9,6% fenólicos totais, 4,5-8,2% ácidos fenólicos, 21,3-21,6% ORAC e 2,8-3,2% DPPH) e as mantidas abertas a 20oC exibiram perdas elevadas (14,4-19,8% fenólicos totais, 11,9-19,6% ácidos fenólicos, 38,8-49,9% ORAC e 2,1- 3,8% DPPH). Após dose única de café para os ratos, o tempo de resposta máxima para as enzimas fase II e ORAC foi de 1 hora, com significância estatística para as enzimas (p=0,015 SOD e Cat, p=0,007 GPx e p=0,403 ORAC). Após diferentes doses, foram obtidas correlações dose-resposta positivas e com significância estatística para as enzimas (p=0,050 SOD, p=0,033 Cat, p=0,008 GPx e p=0,113 ORAC). Após doses repetidas (30 dias), a atividade das enzimas antioxidantes e o ORAC apresentaram grandes aumentos (74,8% SOD, 59,4% Cat, 135,2% GPx e 25,1% ORAC), todos estatisticamente significativos (p<0,001 para todos). O tecido hepático e os biomarcadores não apresentaram alterações em relação ao grupo controle. Conclusões: o café regular apresentou capacidade antioxidante superior ao descafeinado, os dois cafés não apresentaram perdas das características antioxidantes após seis meses se mantidos selados à vácuo e a administração oral de café regular aumentou a condição antioxidante dos ratos de maneira significativa, sem causar danos hepáticos.Introduction: A risk factor for several degenerative diseases is the excess of reactive species caused by oxidative stress. Phenolic acids share in the defense against those species, acting as antioxidants and as transcriptional factors for the phase II antioxidant enzymes (superoxide dismutase, catalase and glutathione peroxidase). Several foods have phenolic acids in their composition but coffee stands out by the high contend of them and to be consumed worldwide. Objectives: a) Compare the antioxidant capacity and the stability of regular and decaffeinated coffees along six months; b) Verify the time of response and possible dose-response correlations of antioxidant effect in rats after a single dose of coffee; c) Evaluate the antioxidant effect and possible hepatic damages in rats submitted to repetitive doses along 30 days. Methods: in the in vitro step, it was analyzed the total phenolic compounds, main phenolic acids, antioxidant capacity (ORAC and DPPH) and the stability of these parameters in regular and decaffeinated coffees along six months. In the in vivo step, it was used male Wistar rats, being analyzed phase II enzymes and ORAC, besides histopathologic examination and biomarkers. Results: regular coffee presented a higher initial antioxidant capacity than decaffeinated coffee with equal total phenolic compounds and higher contend of phenolic acids (15.3% caffeic, 17.0% p-coumaric and 38.1% ferulic), ORAC (20.8%) and DPPH (3.9%). After six months, closed samples kept under vacuum practically did not show any losses, opened samples kept at 4oC presented regular losses (9.6% total phenolic compounds, 4.5-8.2% phenolic acids, 21.3-21.6% ORAC and 2.8-3.2% DPPH) and opened samples kept at 20oC exhibited big losses (14.4-19.8% total phenolic compounds, 11.9-19.6% phenolic acids, 38.8-49.9% ORAC and 2.1-3.8% DPPH). After a single dose of coffee for rats, time for maximum response of phase II enzymes and ORAC was 1 hour, with statistic significance for enzymes (p=0.015 SOD and Cat, p=0.007 GPx and p=0.403 ORAC). After different doses, it was obtained positive dose-response correlations, with statistic significance for enzymes (p=0.050 SOD, p=0.033 Cat, p=0.008 GPx and p=0.113 ORAC). After repetitive doses (30 days), the activity of antioxidant enzymes and ORAC showed big increases (74.8% SOD, 59.4% Cat, 135.2% GPx and 25.1% ORAC), all with statistic significance (p<0.001 for all). Hepatic tissue and biomarkers did not show any change compared to control group. Conclusions: regular coffee presented higher antioxidant capacity than decaffeinated coffee, both coffees did not show any antioxidant losses after six months if kept sealed under vacuum and the oral administration of regular coffee increased significantly the antioxidant condition of rats, without any hepatic damages.
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Scott, Brigitte Clare. "Analysis of the antioxidant action of potential food antioxidants and therapeutic agents." Thesis, King's College London (University of London), 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.338445.
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Funari, Cristiano Soleo de [UNESP]. "Estudos químicos e biológicos de espécies do gênero Lippia (Verbenaceae) nativas no Cerrado paulista." Universidade Estadual Paulista (UNESP), 2010. http://hdl.handle.net/11449/105823.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
A criação de um modelo nacional de saúde pautado nas aptidões e carências brasileiras é tida como fundamental para tornar o acesso à saúde pública mais abrangente e de melhor qualidade. O histórico do desenvolvimento mundial de medicamentos, a biodiversidade e os conhecimentos tradicionais associados a esta, e as competências científicas existentes no Brasil evidenciam a importância da bioprospecção. O gênero Lippia é amplamente empregado em etnomedicina e é constituído principalmente por espécies aromáticas. As investigações químicas e farmacológicas estão majoritariamente concentradas nos seus óleos essenciais, mas alguns componentes fixos, como flavonóides, fenilpropanóides, naftoquinóides e iridóides glicosilados já foram relatados. O Brasil abriga a maioria das espécies deste gênero, mas diversos problemas taxonômicos dificultam o estabelecimento de dados precisos. O stress oxidativo é apontado como ponto central no desenvolvimento de processos degenerativos associados ao envelhecimento e a diversas doenças. Conseqüentemente, terapias antioxidantes estão sendo propostas para o seu tratamento ou prevenção. Este trabalho descreve o fracionamento de extratos de folhas e de ramos de L. salviaefolia guiado por testes antioxidantes que levou ao isolamento de 16 substâncias fenólicas, sendo 4 isômeros interconversíveis inéditos, 2S e 2R-3',4',5,6-tetraidroxi-7-O-β-glicopiranosil-flavanona (12a e 12b) e 2S e 2R-5,8,3',4'-tetraidroxi-7-O-β-glicopiranosil-flavanona (13a e 13b), que foram identificadas em mistura por estudos extensivos de Ressonância Magnética Nuclear e Espectrometria de Massas. Foram isoladas também 8 substâncias do extrato de raízes de L. lupulina, selecionado com base em estudos iniciais de desreplicação por Cromatografia Líquida de Alta Eficiência acoplada a Arranjo de Fotodiodos (CLAE-DAD). Os extratos...
The creation of a national model of health guided by need and capacity in Brazil is seen as fundamental to making access to public health more comprehensive and of better quality. The historical development of world medicine, the biodiversity and traditional knowledge associated with this, and the scientific expertise available in Brazil highlight the significance of bioprospecting in this country. The genus Lippia is widely used in ethnomedicine. Since most of its species are aromatic, the studies on the chemistry and pharmacology of this genus are mainly focused in essential oils, but some fix compounds, such as flavonoids, phenylpropanoids, naphthoquinoids and iridoids glucosides have also been reported. It is estimated that Brazil hosts most of Lippia species, but several taxonomical problems related to this species hamper the establishment of accurate data difficult. Oxidative stress has a central role in the development of degenerative processes associated to aging and several diseases, including cancer and inflammation. Consequently, antioxidant therapies are being proposed for their treatment or prevention. This work describes the fractionation procedures of L. salviaefolia leaves and stems extracts guided by simple antioxidant assays which led to 16 phenolic compounds, including 4 novel interconverting isomers (2S) and (2R)-3',4',5,6-tetrahydroxyflavanone-7-O-β-glucopyranoside (12a and 12b) and (2S) and (2R)-3',4',5,8-tetrahydroxyflavanone-7-O-β-glucopyranoside (13a and 13b), which were identified in mixture by extensive use of 1D and 2D NMR and MS techniques. Additionaly, other 8 compounds were isolated from the extract of roots of L. lupulina, which led to its selection for dereplication studies by High Pressure Liquid Chromatography-Photodiode Array Detector (HPLC-DAD). The bioactivity evaluation of extracts and isolated compounds from L. salviaefolia was initiated... (Complete abstract click electronic access below)
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Giada, Maria de Lourdes Reis. "Avaliação da capacidade antioxidante dos compostos fenólicos do cotilédone da semente de girassol (Helianthus annuus L.) rajada." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/9/9132/tde-22082017-093259/.
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No presente trabalho foi avaliada a capacidade antioxidante in vitro dos extratos do cotilédone da semente de girassol rajada, obtidos por extração seqüencial com solventes de diferentes polaridades, bem como avaliado o potencial antioxidante in vitro do extrato que apresentou maior capacidade in vitro. Todos os parâmetros in vitro (sistema β-caroteno/ácido Iinoléico, métodos FRAP, DPPH, ORAC e Rancimat) indicaram o extrato aquoso (EAq) como o de maior capacidade. Neste extrato, o ácido clorogênico (12,88%) foi identificado como o principal componente dos ácidos fenólicos. Na avaliação da capacidade antioxidante in vitro, ambas as determinações empregadas (TBARS e perfil de ácidos graxos) indicaram o EAq como capaz de exercer um efeito protetor sobre os ácidos graxos poliinsaturados dos tecidos adiposo, cerebral, hepático e plasmático de ratos Wistar machos recém-desmamados.The aims of this work were to evaluate the in vitro antioxidant capacity of listed sunflower cotyledon extracts, obtained by a sequential extraction with solvents of different polarities, and to evaluate the in vitro antioxidant potential of the sample extract with highest in vitro capacity. Ali the in vitro parameters (β-carotene/linoleic acid system, FRAP, OPPH, ORAC and Rancimat methods) indicated the aqueous extract (EAq) as the extract with highest capacity. In this extract, the chlorogenic acid (12.88%) was identified as the principal fraction of phenolic acids. In the in vitro antioxidant capacity evaluation, both determinations used (TBARS and fatty acids profile) gave indication that the EAq was capable to exerce a protective effect on the polyunsaturated fatty acids of the adipose, cerebral, hepatic and plasm tissues of Wistar male rats just-weaned.
Books on the topic "Antioxidant"
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Gupta, Dharmendra K., José M. Palma, and Francisco J. Corpas, eds. Antioxidants and Antioxidant Enzymes in Higher Plants. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-75088-0.
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Cirilo, Giuseppe, and Francesca Iemma, eds. Antioxidant Polymers. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2012. http://dx.doi.org/10.1002/9781118445440.
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The antioxidant recipe book. London: Thorsons, 1994.
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Prenzler, Paul D., Danielle Ryan, and Kevin Robards, eds. Handbook of Antioxidant Methodology. Cambridge: Royal Society of Chemistry, 2021. http://dx.doi.org/10.1039/9781839165337.
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Aftab, Tariq, and Khalid Rehman Hakeem, eds. Antioxidant Defense in Plants. Singapore: Springer Nature Singapore, 2022. http://dx.doi.org/10.1007/978-981-16-7981-0.
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Shahidi, Fereidoon, and Chi-Tang Ho, eds. Antioxidant Measurement and Applications. Washington, DC: American Chemical Society, 2007. http://dx.doi.org/10.1021/bk-2007-0956.
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Skinner, Carrie. Antioxidant supplementation during chemotherapy. Portland, Or: NCNM, 2007.
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1940-, Chow Ching Kuang, ed. Cellular antioxidant defense mechanisms. Boca Raton, Fla: CRC Press, 1988.
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Meeting, American Chemical Society. Antioxidant measurement and applications. Edited by Shahidi Fereidoon 1951-, Ho Chi-Tang 1944-, and American Chemical Society. Division of Agricultural and Food Chemistry. Washington, DC: American Chemical Society, 2007.
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1940-, Chow Ching Kuang, ed. Cellular antioxidant defense mechanisms. Boca Raton, Florida: C.R.C. Press, 1988.
Find full textBook chapters on the topic "Antioxidant"
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Bährle-Rapp, Marina. "antioxidant." In Springer Lexikon Kosmetik und Körperpflege, 41. Berlin, Heidelberg: Springer Berlin Heidelberg, 2007. http://dx.doi.org/10.1007/978-3-540-71095-0_707.
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Abrams, David B., J. Rick Turner, Linda C. Baumann, Alyssa Karel, Susan E. Collins, Katie Witkiewitz, Terry Fulmer, et al. "Antioxidant." In Encyclopedia of Behavioral Medicine, 105–6. New York, NY: Springer New York, 2013. http://dx.doi.org/10.1007/978-1-4419-1005-9_856.
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Nahler, Gerhard. "antioxidant." In Dictionary of Pharmaceutical Medicine, 9. Vienna: Springer Vienna, 2009. http://dx.doi.org/10.1007/978-3-211-89836-9_75.
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Gooch, Jan W. "Antioxidant." In Encyclopedic Dictionary of Polymers, 43–44. New York, NY: Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4419-6247-8_708.
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Aldred, Sarah. "Antioxidant." In Encyclopedia of Behavioral Medicine, 1. New York, NY: Springer New York, 2019. http://dx.doi.org/10.1007/978-1-4614-6439-6_856-2.
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Aldred, Sarah. "Antioxidant." In Encyclopedia of Behavioral Medicine, 124. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-39903-0_856.
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Gooch, Jan W. "Antioxidant." In Encyclopedic Dictionary of Polymers, 874. New York, NY: Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4419-6247-8_13152.
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Sun, Ting, and Joseph R. Powers. "Antioxidants and Antioxidant Activities of Vegetables." In Antioxidant Measurement and Applications, 160–83. Washington, DC: American Chemical Society, 2007. http://dx.doi.org/10.1021/bk-2007-0956.ch012.
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Xiong, Youling L. "Antioxidant Peptides." In Bioactive Proteins and Peptides as Functional Foods and Nutraceuticals, 29–42. Oxford, UK: Wiley-Blackwell, 2010. http://dx.doi.org/10.1002/9780813811048.ch3.
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Agarwal, Ashok, Damayanthi Durairajanayagam, Gurpriya Virk, and Stefan S. Du Plessis. "Antioxidant Strategies." In Strategies to Ameliorate Oxidative Stress During Assisted Reproduction, 23–38. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-10259-7_3.
Full textConference papers on the topic "Antioxidant"
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Hil'sher, M. S., and Anna Vesnina. "ANTIOXIDANT ACTIVITY OF CHLORELLA VULGARIS EXTRACTS." In I International Congress “The Latest Achievements of Medicine, Healthcare, and Health-Saving Technologies”. Kemerovo State University, 2023. http://dx.doi.org/10.21603/-i-ic-141.
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Peng, Han, and Fereidoon Shahidi. "Antioxidant activity of EGC (epigallocatechin) ester derivatives in food and biological model system." In 2022 AOCS Annual Meeting & Expo. American Oil Chemists' Society (AOCS), 2022. http://dx.doi.org/10.21748/qchb4629.
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Objective: Antioxidants retard oxidative processes in food and pharmaceuticals as well as in the body. However, potential adverse effects of synthetic antioxidants and insufficient efficacy of current natural/natural-derived antioxidant substitutes necessitate developing novel antioxidants. Thus, EGC, as one of the most widely distributed dietary flavanols, serves as an efficient natural antioxidant with numerous health effects, but it is relatively poorly soluble in lipophilic media. In this study, novel lipophilic EGC derivatives prepared via enzymatic esterification will be evaluated in controlling oxidation in food and biological systems.
Methods: EGC esters were prepared under optimized reaction conditions, including enzyme type, substrate ratio (Acyl acceptor/acyl donor), and reaction time. The purified products were then tested for their antioxidant ability using β-carotene bleaching, LDL (low-density lipoprotein) oxidation, and DNA scission assays.
Results: In the β-carotene bleaching assay, the oxidation inhibition of EGC and its esters was observed for about 80 min at 50℃ by maintain the yellow colour and then decreased gradually with time. Meanwhile, EGC monoesters (except EGC acetate and stearate) showed a significantly higher inhibition rate than EGC. In the LDL oxidation assay, a similar downtrend of antioxidant ability was observed. However, EGC exhibited higher antioxidant capacity compared to EGC monoesters. In the DNA scission test, the EGC acylated with short-chain fatty acids (C2-C6) showed the higher DNA stability than EGC or other EGC monoesters.
Conclusion: Overall, EGC monoesters displayed significant antioxidant activity in all three assays. The results in biological/food systems were in agreement with our previous chemical antioxidant tests. Moreover, the antioxidant ability of EGC as a natural antioxidant was retained or even enhanced after modification. Thus, acylated EGCs could serve as viable alternatives to traditional synthetic antioxidants.
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Bayram, Ipek, and Eric Decker. "Determination of Antioxidant Synergism Between Tocopherols and Myricetin in Bulk Oil." In 2022 AOCS Annual Meeting & Expo. American Oil Chemists' Society (AOCS), 2022. http://dx.doi.org/10.21748/gxns9591.
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Lipid oxidation is a series of reactions affecting food quality and shelf life since it impacts flavor, color, and nutrition. The food industry utilizes different antioxidants to retard oxidation. Interaction between antioxidants can improve the ability of the industry to protect foods if the antioxidant combination is synergistic. This research aims to determine the conditions where tocopherols and myricetin exhibit synergistic activity in bulk oils. Soybean oil was stripped to remove present endogenous antioxidants to better understand tocopherol-myricetin interaction. The oxidative stability of the oil was determined by spectroscopically measuring lipid hydroperoxides and monitoring aldehyde formation by gas chromatography. Antioxidant degradation was determined by HPLC. α or mixed tocopherols (50 µM), myricetin (10, 25, 50, 100, 250 µM), and their combinations were added to stripped oil to determine how antioxidant ratios impacted synergism. The interaction index is the ratio of the observed lag phase to the expected lag phase of the antioxidant combination. Interaction indexes were 1.14, 1.50, 1.55, 1.30, and 1.16 when tocopherol: myricetin ratio was 5:1, 2:1, 1:1, 1:2, and 1:5, respectively, implicating synergistic activity (interaction index >1). Synergism was greatest when antioxidant concentrations were similar. Tocopherol and myricetin degraded at different rates, suggesting that synergism could be due to either regeneration of one antioxidant by another or preferential oxidation of one antioxidant followed by another. Synergism could also occur by chelating properties of myricetin, which could decrease the tocopherol loss. Tocopherols were found to be completely degraded just before the oxidation of fatty acids. This suggests that modeling the rate of tocopherol degradation could predict shelf-life. This project is significant for the Lipid Oxidation and Quality Division since it supplies ideas and learning opportunities to members who share similar interests in synergistic activity, antioxidant degradation kinetics, and unique strategies to decrease food waste caused by lipid oxidation.
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Zhukovets, T. A., M. А. Khancheuski, I. V. Koktysh, E. I. Kvasyuk, and A. G. Sysa. "ANTIOXIDANT EFFECTS OF EMOXYPINE AS ADJUVANT OF ANTI-CANCER DRUGS." In SAKHAROV READINGS 2021: ENVIRONMENTAL PROBLEMS OF THE XXI CENTURY. International Sakharov Environmental Institute of Belarusian State University, 2021. http://dx.doi.org/10.46646/sakh-2021-2-52-55.
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Antioxidants are known to minimize oxidative stress by interacting with free radicals produced as a result of cell aerobic reactions. Oxidative stress has long been linked to many diseases, especially tumours. Therefore, antioxidants play a crucial role in the prevention or management of free radical-related diseases. However, most of these antioxidants have anticancer effects only if taken in large doses. Therefore, the combined use of antioxidants with chemotherapeutic agents is an attractive strategy to combat various tumours. This article focuses on the antioxidant effect of emoxypine. The contribution of this molecule in enhancing the anticancer potentials of nelarabine will be demonstrated.
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Sovrlić, Miroslav, Nedeljko Manojlović, Marijana Kosanić, Aleksandar Kočović, Jovica Tomović, and Perica Vasiljević. "Lichenochemical analysis and in vitro antioxidant activity of extracts and gyrophoric acid from lichen Umbilicaria grisea." In 2nd International Conference on Chemo and Bioinformatics. Institute for Information Technologies, University of Kragujevac, 2023. http://dx.doi.org/10.46793/iccbi23.515s.
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This research investigates the chemical composition, total phenolic and flavonoid content, and antioxidant activity of acetone, methanol, and ethanol extracts of the lichen Umbilicaria grisea, and its major secondary metabolite, gyrophoric acid. The extracts were analyzed using high-performance liquid chromatography (HPLC-UV) and spectrophotometric assays. The results showed significant levels of phenolic compounds and flavonoids, which contribute to the lichen’s antioxidant potential. The antioxidant activity was evaluated using in vitro assays such as DPPH and ABTS radical scavenging activity. The extracts demonstrated potent antioxidant activity, suggesting their potential as natural antioxidants. The identification of bioactive compounds, high phenolic and flavonoid content, and significant antioxidant activity support the potential use of U. grisea as a natural source of therapeutic agents. Further studies are needed to elucidate the underlying mechanisms responsible for these biological activities and evaluate the efficacy and safety of these extracts for potential pharmaceutical applications.
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Chizzola, Remigius, Harinder Makkar, Ellen McGrath, and Papu Haroon. "EXTRACTION OF ANTIOXIDANTS FROM MORINGA OLEIFERA LEAVES, STABILITY OF THE RESULTING ANTIOXIDANTS, AND USE OF THE REMAINING RESIDUE AS LIVESTOCK FEED." In 23rd SGEM International Multidisciplinary Scientific GeoConference 2023. STEF92 Technology, 2023. http://dx.doi.org/10.5593/sgem2023v/6.2/s25.27.
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Moringa oleifera, commonly known as horse radish tree or drumstick tree is a perennial multipurpose tropical tree. It can be used as medicine, cosmetic and functional food, among others. The benefits of using the leaves are ascribed to the presence of a number of antioxidants. Nowadays it is widely cultivated and naturalized in many countries. Simple methods to extract antioxidants from Moringa leaf are lacking, which were established, stability of antioxidants was assessed, and residue left after extraction was explored for use as animal feed, with the aim to scale-up the process to industrial scale. A natural source antioxidant-rich fraction prepared in this study could have applications in protecting against free radical mediated damage, to enhance shelf-life of products, and to prevent and/or cure diseases. Antioxidants are known to have anti-diabetic, antiinflammatory, anti-aging, cardio-and neuro-protective, intestinal microbiota regulatory effects, among others. The optimized procedure consisted of ultrasonication or extraction in a shaking water bath for 40 minutes at 30�C in 45% aq. ethanol at 1:10 (w/v) plant:solvent ratio. A high extraction yield by weight of 31-33% was obtained. The preparation was rich in antioxidants. On dry weight (DW) basis, total phenolics were from 19.6 to 33.5 mg catechin equivalents/g, FRAP (Ferric Reducing Antioxidant Power) from 83.3 to 140.7 nmol FeSO4 equivalents/g and DPPH (2,2-diphenyl-1-picrylhydrazyl) activity from 8.9 to 18.2 mg Trolox equivalents/g. The HPLC fingerprinting showed the presence of more than a dozen compounds, and the UV spectra were typical for flavonoids and phenolic acids, containing high amounts of chlorogenic acid and rutin. The antioxidants in a liquid state or after freezedrying were stable for over 3 months at room temperature, 4-6�C or - 18�C. The residue left after extraction had 42% crude protein and the essential amino acids contents were as high as that in soymeal. The residue can replace soymeal in dairy and beef cattle diets at 1:1 level by weight, and in fish diet at 30% replacement of fishmeal protein. This can decrease cost of animal feeding by 20-35%, giving higher profit to farmers and industry. Also, this residue is likely to provide health benefit to the animals being rich in catechin and kaempferol. The method developed is low-cost and easy to scale up, especially in a developing country settings. Good stability of the antioxidant preparation makes its attractive for use in cosmetic, pharmaceutical and food industries. It can also be a replacer of synthetic antioxidants in food and feed applications including ethoxyquin (used in fish feed), banned in many countries including the EU. The moringa antioxidant-rich fraction obtained in this study that corresponded to 1 g each of ascorbic acid, ethoxyquin or butylated hydroxytoluene (BHT) (all synthetic antioxidants) was 3.64 g, 4.3 g and 2.1 g, respectively. This antioxidant potential of moringa is very high, among other known oxidants isolated from plant parts. The study is an important step towards industrial scale development of isolating antioxidant-rich fraction and of incorporating the residue in animal diets, with zero waste � a vital requisite for circular economy.
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Du, Zhenjiao, Donghai Wang, and Yonghui Li. "Comprehensive Evaluation and Comparison of Machine Learning Methods in QSAR Modeling of Antioxidant Tripeptides." In 2022 AOCS Annual Meeting & Expo. American Oil Chemists' Society (AOCS), 2022. http://dx.doi.org/10.21748/oppq6042.
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Due to their multiple beneficial effects, antioxidant peptides have attracted increasing interest. Currently, the identification of antioxidative peptides and screening bioactive peptides are based on wet-chemistry methods which are time-consuming and highly rely on many advanced instruments and trained personnel. Compared to wet chemistry methods for preparation and screening bioactive peptides, quantitative structure-activity relationship (QSAR) analysis as an in silicon method can be more efficient and cost-effective. However, model performance of QSAR studies on antioxidant peptides was still poor due to the difficulties from data set division to regression methods. The objective of this study was to compare most popular and promising machine learning methods for antioxidant activity modeling and screening of tripeptides and identify the critical amino acid features that determine the antioxidant activity. We adopted 553 numerical indices of amino acids to characterize 130 tripeptides with known antioxidant activity from published literatures, and then six advanced feature selection methods plus pairwise correlation were used to screen the most important indices for antioxidant activity and model building. Fourteen machine learning methods were used to build models based on the six feature selection methods, respectively. Among the 84 models, the best model with R2Test of 0.847 and MSETest of 0.393 for tripeptide antioxidants was obtained based on FI-RFR plus XGB. Based on the predicted antioxidant values of 7870 unknown tripeptides, the potential high antioxidant activity tripeptides all have a tyrosine, tryptophan, or cysteine at the C-terminal position. In addition, results also showed that C-terminal amino acids contributed the most to antioxidant activity, while the central amino acid contributed the least. Non-linear regression methods were more suitable for QSAR study on antioxidant activity.
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Todorović, Jovana D., Aleksandra D. Vesić, Nevena N. Petrović, and Marijana M. Kosanić. "Edible mushrooms as promising antioxidants." In 2nd International Conference on Chemo and Bioinformatics. Institute for Information Technologies, University of Kragujevac, 2023. http://dx.doi.org/10.46793/iccbi23.300t.
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Antioxidant activity of the acetone extracts of the mushrooms Macrolepiota procera and Chlorophyllum rhacodes has been screened in vitro by using different methods (DPPH radical scavenging and reducing power assay), and also it has been determined the total phenolic compounds as total flavonoid content. The research findings indicate that the acetone extract of M. procera demonstrated superior antioxidant activities when compared to C. rhacodes. Similarly, the mushroom M. procera displayed a more pronounced effect on reducing power. In addition, the total content of phenol and flavonoid in extracts were determined as pyrocatechol equivalent, and as rutin equivalent, respectively. A higher content of total phenols and flavonoids was detected in the extract of M. procera. The strong relationships between total phenolic and flavonoid contents and the antioxidative activities of tested extracts imply that these compounds have a significant impact on antioxidant activity. The present study highlights that the tested mushroom species exhibit potent antioxidant properties and can be regarded as valuable sources of natural antioxidants.
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Nandasiri, Ruchira, Olamide Fadairo, Thu Nguyen, and N. A. Michael Eskin. "Valorization of Oilseeds: Impact of Ph, Hot Air, and Pressurized Cooking on Major Phenolic Derivatives." In 2022 AOCS Annual Meeting & Expo. American Oil Chemists' Society (AOCS), 2022. http://dx.doi.org/10.21748/caol6088.
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The phenolic compounds in canola and mustard, sinapine, sinapic acid, and canolol, are recognized for their antioxidant, anti-inflammatory, and anti-carcinogenic health-promoting effects. Previous studies demonstrated the effectiveness of different pretreatment conditions on the extraction process by enhancing the yield of phenolic antioxidants such as canolol. In the present study, different pre-treatment conditions were evaluated, including pH, hot air, and pressurized cooking, to optimize the extraction of phenolic compounds from canola and mustard seeds. Sautéing for 10 minutes prior to the extraction was found to significantly increase the canolol content of the mustard seeds. Whereas hot air pre-treatment at 190oC for 10 minutes prior to extraction increased the canolol content of the canola seeds. These findings confirmed that different pre-treatment techniques prior to the extraction of oils from the oilseeds increased their antioxidant potential and their economic value. These results also confirmed that changes in the pH conditions from acidic (pH < 7) to neutral (pH = 7) had a positive impact on the extraction of phenolic antioxidants including canolol. These results will benefit both the canola and mustard industry by producing better quality oils with enhanced antioxidant properties and shelf-lives.
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Fomenko, M. P., A. M. Menzheritsky, and G. V. Karantysh. "INFLUENCE OF PINEALON ON EXPRESSION OF GENES OF PRO- AND ANTIOXIDANT ENZYMES AND FREE RADICAL PROCESSES IN RATS IN THE MODEL OF SUGAR DIABETES." In STATE AND DEVELOPMENT PROSPECTS OF AGRIBUSINESS Volume 2. DSTU-Print, 2020. http://dx.doi.org/10.23947/interagro.2020.2.232-234.
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The article presents an analysis of the effect of pinealon on free radical processes and the level of expression of the SOD1, GPX4 and GSR genes in the rat hippocampus in a model of streptozotocininduced diabetes (type I diabetes mellitus). It has been established that when modeling diabetes in the hippocampus, intensification of radically radical processes is observed: the level of prooxidants increases, the level of antioxidants decreases, as well as the level of expression of antioxidant genes. With the introduction of pinealone in dosages of 50 or 100 ng/kg in the model of diabetes mellitus, the pro-antioxidant balance shifts towards a decrease in the production of free radicals and an increase in antioxidant protection. Pinealon at a dosage of 100 ng/kg is more effective.
Reports on the topic "Antioxidant"
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Paul, Satashree. Oxidative Stress: A Cause of Male Infertility. Science Repository OÜ, October 2020. http://dx.doi.org/10.31487/sr.blog.10.
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Watkins, Chris B., Susan Lurie, Amnon Lers, and Patricia L. Conklin. Involvement of Antioxidant Enzymes and Genes in the Resistance Mechanism to Postharvest Superficial Scald Development. United States Department of Agriculture, December 2004. http://dx.doi.org/10.32747/2004.7586539.bard.
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The objective of this research project was to evaluate the involvement of antioxidant enzymes and genes in the resistance mechanism to postharvest superficial scald development using two primary systems: 1. Resistant and susceptible progenies of an apple cross between a scald resistant crab apple, ‘White Angel’ and a scald susceptible cultivar, ‘Rome Beauty’; 2. Heat-treatment of ‘Granny Smith’, which is known to reduce scald development in this cultivar. In 2002 we asked for, and received (October 14), permission to revise our initial objectives. The US side decided to expand their results to include further work using commercial cultivars. Also, both sides wanted to include an emphasis on the interaction between these antioxidant enzymes and the á-farnesene pathway, with the cooperation of a third party, Dr. Bruce Whitaker, USDA-ARS, Beltsville. Background: Superficial scald is a physiological storage disorder that causes damage to the skin of apple and pear fruit. It is currently controlled by use of an antioxidant, diphenylamine (DPA), applied postharvest by drenching or dips, but concern exists about such chemical usage especially as it also involves application of fungicides. As a result, there has been increased emphasis on understanding of the underlying mechanisms involved in disorder development. Our approach was to focus on the oxidative processes that occur during scald development, and specifically on using the two model systems described above to determine if the levels of specific antioxidants and/or antioxidant enzyme activities correlated with the presence/absence of scald. It was hoped that information about the role of antioxidant-defense mechanisms would lead to identification of candidate genes for future transgenic manipulation. Major conclusions, solutions, achievements: Collectively, our results highlight the complexity of superficial scald developmental processes. Studies involving comparisons of antioxidant enzyme activities in different crab apple selection, commercial cultivars, and in response to postharvest heat and 1-methylcyclopropene (1-MCP) treatments, show no simple direct relationships with antioxidant contents and susceptibility of fruit to scald development. However, a correlative relationship was found between POX activity or isoenzyme number and scald resistance in most of the studies. This relationship, if confirmed, could be exploited in breeding for scald resistance. In addition, our investigations with key genes in the á-farnesenebiosynthetic pathway, together with antioxidant processes, are being followed up by analysis of exposed and shaded sides of fruit of cultivars that show different degrees of scald control by 1-MCP. These data may further reveal productive areas for future research that will lead to long term control of the disorder. However, given the complexity of scald development, the greatest research need is the production of transgenic fruit with down-regulated genes involved in á- farnesene biosynthesis in order to test the currently popular hypothesis for scald development.
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Zhu, Chao-Zhi, Joseph G. Sebranek, and Dong U. Ahn. Antioxidant Peptides in Commercial Dry-Cured Hams. Ames (Iowa): Iowa State University, January 2016. http://dx.doi.org/10.31274/ans_air-180814-1388.
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Ananieva, Kalina, Emilia Gesheva, Kiril Mishev, and Marina Stanilova. Antioxidant Capacity of Two Endemic Verbascum Species. "Prof. Marin Drinov" Publishing House of Bulgarian Academy of Sciences, June 2020. http://dx.doi.org/10.7546/crabs.2020.06.08.
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Cuellar, Jr, and J. P. Fuel Property and Antioxidant Effects on Elastomer Integrity. Fort Belvoir, VA: Defense Technical Information Center, March 1988. http://dx.doi.org/10.21236/ada200250.
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Prasad, Kedar. Antioxidant Micronutrients: Therapeutic Counter Measures for Chemical Agents. Fort Belvoir, VA: Defense Technical Information Center, March 2011. http://dx.doi.org/10.21236/ada554277.
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Kanner, Joseph, Edwin Frankel, Stella Harel, and Bruce German. Grapes, Wines and By-products as Potential Sources of Antioxidants. United States Department of Agriculture, January 1995. http://dx.doi.org/10.32747/1995.7568767.bard.
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Several grape varieties and red wines were found to contain large concentration of phenolic compounds which work as antioxidant in-vitro and in-vivo. Wastes from wine production contain antioxidants in large amounts, between 2-6% on dry material basis. Red wines but also white wines were found to prevent lipid peroxidation of turkey muscle tissues stored at 5oC. The antioxidant reaction of flavonoids found in red wines against lipid peroxidation were found to depend on the structure of the molecule. Red wine flavonoids containing an orthodihydroxy structure around the B ring were found highly active against LDL and membrane lipid peroxidation. The antioxidant activity of red wine polyphenols were also found to be dependent on the catalyzer used. In the presence of H2O2-activated myoglobin, the inhibition efficiency was malvidin 3-glucoside>catechin>malvidin>resveratol. However, in the presence of an iron redox cycle catalyzer, the order of effectiveness was resveratol>malvidin 3-glucoside = malvidin>catechin. Differences in protein binding were found to affect antioxidant activity in inhibiting LDL oxidation. A model protein such as BSA, was investigated on the antioxidant activity of phenolic compounds, grape extracts, and red wines in a lecithin-liposome model system. Ferulic acid followed by malvidin and rutin were the most efficient in inhibiting both lipid and protein oxidation. Catechin, a flavonal found in red-wines in relatively high concentration was found to inhibit myoglobin catalyzed linoleate membrane lipid peroxidation at a relatively very low concentration. This effect was studied by the determination of the by-products generated from linoleate during oxidation. The study showed that hydroperoxides are catalytically broken down, not to an alcohol but most probably to a non-radical adduct. The ability of wine-phenolics to reduce iron and from complexes with metals were also demonstrated. Low concentration of wine phenolics were found to inhibit lipoxygenase type II activity. An attempt to understand the bioavailability in humans of antocyanins from red wine showed that two antocyanins from red wine were found unchanged in human urine. Other antocyanins seems to undergo molecular modification. In hypercholesterolemic hamsters, aortic lipid deposition was significantly less in animals fed diets supplemented with either catechin or vitamin E. The rate of LDL accumulation in the carotid arteries was also significantly lower in the catechin and vitamin E animal groups. These results suggested a novel mechanism by which wine phenolics are associated with decreased risk of coronary heart diseases. This study proves in part our hypothesis that the "French Paradox" could be explained by the action of the antioxidant effects of phenolic compounds found at high concentration in red wines. The results of this study argue that it is in the interest of public health to increase the consumption of dietary plant falvonoids. Our results and these from others, show that the consumption of red wine or plant derived polyphenolics can change the antioxidant tone of animal and human plasma and its isolated components towards oxidative reactions. However, we need more research to better understand bioavailability and the mechanism of how polyphenolics affect health and disease.
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Kumar, A. P. Antioxidant Prophylaxis in the Prevention of Prostatic Epithelial Neoplasia. Fort Belvoir, VA: Defense Technical Information Center, February 2009. http://dx.doi.org/10.21236/ada503781.
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Sebranek, Joseph G., Vincent J. H. Sewalt, Kristen L. Robbins, and Terry A. Houser. Antioxidant Effectiveness of Natural Rosemary Extract in Pork Sausage. Ames (Iowa): Iowa State University, January 2004. http://dx.doi.org/10.31274/ans_air-180814-955.
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Aleksandrov, A. V., L. N. Shilova, N. V. Aleksandrova, I. V. Cherkachina, E. E. Mozgovaya, N. I. Emelianov, V. A. Aleksandrov, and M. V. Nikitin. On the antioxidant status in patients with rheumatoid arthritis. FilodirittoEditore, 2018. http://dx.doi.org/10.18411/978-88-85813-04-5-2018-10-413-419.
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