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Antioxidant Components (antioxidant + component)
Selected AbstractsCompositional Characteristics and Antioxidant Components of Cherry Laurel Varieties and PekmezJOURNAL OF FOOD SCIENCE, Issue 1 2005Cesarettin Alasalvar ABSTRACT: Cherry laurel is a popular fruit in the Black Sea region of Turkey. Two native cherry laurel varieties, namely kiraz and findik, together with pekmez (made from concentrated juice of the kiraz variety by boiling/ heating) were examined for their proximate composition, antioxidant activity, total anthocyanins, phenolics, and carotenoids, as well as phenolic acids and sugar composition. A linear correlation existed between antioxidant activity and total content of phenolics (r2= 0.99). The antioxidant activity and total content of phenolics were the highest in pekmez, followed by findik, and kiraz. A significant (P < 0.01) proportion of anthocyanins and carotenoids was lost during heat processing in the production of pekmez. Ten phenolic acids (free and bound) and 6 sugars were identified among samples. These results suggest that cherry laurel varieties and pekmez serve as a good source of natural antioxidant, which could potentially be used in food and nutraceutical supplement formulations. [source] Effect of different cooking methods on the antioxidant activity of some vegetables from PakistanINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 3 2008Bushra Sultana Summary The effects of different cooking methods (boiling, frying and microwave cooking) on the antioxidant activity of some selected vegetables (peas, carrot, spinach, cabbage, cauliflower, yellow turnip and white turnip) were assessed by measuring the total phenolic contents (TPC), reducing power and percentage inhibition in linoleic acid system. TPC (gallic acid equivalents g/100 g of dry weight) and reducing power of the methanolic extracts of raw-, microwaved-, boiled- and fried vegetables ranged 0.333,2.97, 0.52,2.68, 0.48,2.08, 1.00,2.02 and 0.391,2.24, 0.822,1.10, 0.547,1.16, 0.910,4.07, respectively. The level of inhibition of peroxidation ranged 71.4,89.0, 66.4,87.3, 73.2,89.2 and 77.4,91.3%, respectively. Antioxidant activity of the vegetables examined was appreciably affected because of varying cooking treatments. TPC of vegetables, generally, decreased by boiling, frying and microwave cooking. There was a significant (P < 0.05) increase in reducing power as a result of frying. However, boiling and microwave cooking did not affect reducing power. Inhibition of peroxidation increased by boiling and frying, whereas, in contrast it was decreased by microwave cooking. The results of the present investigation showed that all the cooking methods affected the antioxidant properties of the vegetables; however, microwave treatment exhibited more deleterious effects when compared with those of other treatments. Thus an appropriate method might be sought for the processing of such vegetables to retain their antioxidant components at maximum level. [source] SUBCRITICAL WATER EXTRACTION OF CAFFEINE FROM BLACK TEA LEAF OF IRANJOURNAL OF FOOD PROCESS ENGINEERING, Issue 3 2008ANVAR SHALMASHI ABSTRACT This study examines subcritical water extraction (SCWE) of caffeine from black tea leaf. The effects of various operating conditions such as water temperature (100, 125, 150 and 175C), water flow rate (1, 2 and 4 g/min), mean particle size (0.5, 1 and 2 mm) on extraction yield and rate were determined. SCWE at 175C, water flow rate of 2 g/min and mean particle size of 0.5 mm were found to be able to recover 3.82% (w/w) of caffeine present in the black tea leaf within 3 h of extraction. In comparison to the SCWE, conventional hot water extraction showed 3.30% (w/w) extraction yield. It was found also that pressure had no effect on extraction yield and rate. PRACTICAL APPLICATIONS Recently, subcritical water has become of great interest as an alternative solvent for extraction of natural active compounds. Subcritical water, as a green solvent, can be used in many different fields of applications. In recent years, extraction of flavors, fragrances and antioxidant components from plant materials, and hydrolysis of carbohydrates, vegetable oils and fatty acids have been widely investigated by many researchers. Using subcritical water for analytical purposes, for soil remediation and applying it as a reaction media are some other interesting fields for practical applications. Subcritical water is an excellent solvent for caffeine as well as many other organic compounds but is safer than the organic solvents that are used for caffeine extraction. [source] EFFECTS OF ACIDIFICATION ON PE ACTIVITY, COLOR AND ANTIOXIDANT PROPERTIES OF COLD BREAK TOMATO JUICEJOURNAL OF FOOD QUALITY, Issue 1 2008FALLOU SARR ABSTRACT Turbidity maintenance, high antioxidant activity and attractive red color are important attributes of good tomato juice. Acidification was found effective in pectin esterase (PE) inactivation and turbidity maintenance. However, no information related to the changes of antioxidant properties after enzyme inactivation by acidification has been reported. In this article, acidification of cold break tomato juice to pH 2 or 3 was conducted after extraction. The changes of antioxidant properties (content and activity) and their correlation with PE activity and color in the juice were studied. Results indicated that acidification enhanced the viscosity of tomato juice by decreasing its PE activity. Significant increases of the main antioxidant contents (lycopene, polyphenols and vitamin C) and antioxidant activities (1,1-diphenyl-2-picrylhydrazyl scavenging, ferrous ion chelating ability [FICA] and reducing power), as well as red color, were also found. In addition, the acidified cold break tomato juice exhibited better FICA and reducing power than butylated hydroxyanisole and, -tocopherol. This finding reveals the possibility of producing tomato juice with high antioxidant capacities by acidification. PRACTICAL APPLICATIONS The consumers' demand for healthy products with high quality toward fresh and health has increased remarkably these years. Tomato is one of the most popular vegetable juices, and its important quality aspects are color, stability and antioxidant capacity. Pectin esterase is the principal agent responsible for tomato juice stability. In addition, the goal of tomato juice processors is to optimize processing conditions by prevention of heat and oxidative damages on antioxidant components. Our results indicated that acidification may stabilize tomato juice and improve its color characteristics and main nutritional factors. Therefore, the acidification treatment could be used as a tool for providing the attractive color and enhancing the nutritional value and health-promoting properties of cold break tomato juice. [source] Physicochemical, Nutritional, and Functional Characterization of Fruits Xoconostle (Opuntia matudae) Pears from Central-México RegionJOURNAL OF FOOD SCIENCE, Issue 6 2010Salvador H. Guzmán-Maldonado Abstract:, Xoconostle cv. Cuaresmeño (Opuntia matudae) has attracted domestic and international industry attention; however, variations of composition from xoconostle structures have not been evaluated. Industries discard the pulp (endocarp) and peel (pericarp) as wastes and utilize the skin (mesocarp), which is the edible portion. The physicochemical, nutritional, and functional characterization of structures from xoconostle pear from 3 major sites of production in Mexico were assessed. Skin yield ranged from 58% to 64% and was higher to that of peel (22% to 24%) and pulp (12% to 18%) yields. pH, °Brix, and acidity were similar among xoconostle structures. Total fiber showed by peel (18.23% to 20.37%) was 2-fold higher than that of skin. Protein and ether extract were higher in xoconostle pulp compared to that showed by peel and skin. Iron content of xoconostle peel (6 to 9.6 mg/100 g, DWB) was higher to that of skin and pulp and prickly pear pulp. Soluble phenols of peel (840 to 863 mg GAE/100 g, DWB) were almost similar to that of skin (919 to 986 mg GAE/100 g, dry weigh basis); meanwhile, ascorbic acid concentration of skin was 2-fold higher compared to that of peel. The phenolic fraction of xoconostle structures consisted of gallic, vanillic, and 4-hydroxybenzoic acids; catechin, epicatechin, and vanillin were also identified by high-performance liquid chromatography,didoe array detection (HPLC-DAD). Xoconostle peel showed higher antioxidant activity (TEAC) compared to that of skin (2-fold) and pulp (6-fold) of commonly consumed fruits and vegetables. The potential of xoconostle peel and pulp for the production of feed or food is promissory. Practical Application:, Outstanding nutritional and functional properties of xoconostle cv. Cuaresmeño fruits are demonstrated. Increased consumption could contribute positively to improve the diet of rural and urban consumers. The high fiber, mineral, and antioxidant components of xoconostle peel and pulp suggest that these fruit structures, which are currently discarded as waste, have promissory use as feed or food by industry. [source] Rapid identification and preparative isolation of antioxidant components in licoriceJOURNAL OF SEPARATION SCIENCE, JSS, Issue 4-5 2010Yeon Sil Lee Abstract This study employed the online HPLC-2,2,-azinobis-(3-ethylbenzothiazoline-6-sulfonate radical cation (ABTS+·) bioassay to rapidly determine antioxidant compounds occurring in the licorice extract of Glycyrrhiza uralensis. The negative peaks of the ABTS+· radical scavenging detection system, which indicated the presence of antioxidant activity, were monitored by measuring the decrease in absorbance at 734,nm. The ABTS+ -based antioxidant activity profile showed that three peaks exhibited antioxidant activity, and then the high-speed counter-current chromatography technique of preparative scale was successfully applied to separate the three peaks I-III in one step from the licorice extract. The high-speed counter-current chromatography was performed using a two-phase solvent system composed of n -hexane,ethyl acetate,methanol,water (6.5:5.5:6:4, v/v). Yields of the three peaks, dehydroglyasperin C (I, 95.1% purity), dehydroglyasperin D (II, 96.2% purity), and isoangustone A (III, 99.5% purity), obtained were 10.33, 10.43, and 6.7% respectively. Chemical structures of the purified dehydroglyasperin C (I), dehydroglyasperin D (II), and isoangustone A (III) were identified by ESI-MS and 1H- and 13C-NMR analysis. [source] Effect of plant phenolics, tocopherol and ascorbic acid on oxidative stability of pork pattiesJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 8 2009Lindsey Haak Abstract BACKGROUND: There is great interest in the use of naturally occurring antioxidants to delay oxidation in meat products. The effect of rosemary extract (RE), green tea extract (TE), tocopherol, trolox, ascorbic acid (AA) and ascorbyl palmitate (AP), at levels of 50,200 ppm of antioxidant components, on colour (CIE L*a*b*), lipid (TBARS) and protein oxidation (thiol groups) in fresh, frozen and cooked pork patties during illuminated chill storage was investigated. Individual components of RE and TE were also tested. RESULTS: RE, TE, AP, tocopherol and trolox equally inhibited lipid oxidation in fresh and frozen patties, whereas for cooked patties RE was most effective. AA stimulated lipid oxidation. No dose effect in the range of 50,200 ppm was found for fresh and frozen patties, whereas for cooked patties higher doses of RE and TE more efficiently prevented lipid oxidation. Protein oxidation was hardly influenced by antioxidant treatment. Colour stability decreased as follows: tocopherol, AA and AP > RE and TE > trolox. Antioxidant properties of the extracts and their major antioxidant components were comparable. CONCLUSION: The relative effect of the antioxidants depends on the oxidation parameter assessed, the applied dose and the hydrophilic/lipophilic character. Copyright © 2009 Society of Chemical Industry [source] Differential response of antioxidant compounds to salinity stress in salt-tolerant and salt-sensitive seedlings of foxtail millet (Setaria italica)PHYSIOLOGIA PLANTARUM, Issue 4 2000N. Sreenivasulu The modulation of antioxidant components was comparatively analysed in a salt-tolerant (cv. Prasad) and salt-sensitive (cv. Lepakshi) cultivar of foxtail millet (Setaria italica L.) under different NaCl concentrations. Under conditions of salt stress, the salt-tolerant cultivar exhibited increased total superoxide dismutase (SOD) and ascorbate peroxidase (APX) activity, whereas both enzyme activities decreased in acutely salt-stressed seedlings of the sensitive cultivar. At 200 mM NaCl, the tolerant foxtail millet cultivar responded with induction of cytosolic Cu/Zn-SOD and the Mn-SOD isoform at the protein level. The induced accumulation of the cytosolic Cu/Zn-SOD protein/activity is positively correlated with an elevated level of the cytosolic APX gene activity. The elevated cytosolic Cu/Zn-SOD and cytosolic APX activity correlates with an induced accumulation of their transcripts. Tolerant 5-day-old seedlings grown during high salinity treatment (200 mM NaCl) contained a lower amount of Na+ ions and showed a lower electrolyte leakage than sensitive seedlings. In conclusion, our comparative studies indicate that salt-induced oxidative tolerance is conferred by an enhanced compartment-specific activity of the antioxidant enzymes in response to compartment-specific signals. [source] Genomics of berry fruits antioxidant componentsBIOFACTORS, Issue 4 2005E. D'Amico Abstract Reactive oxygen and nitrogen metabolites, which are side products of cell metabolism, can produce a lot of damage in biological macromolecules and tissues, producing a number of chronic illnesses. On the other hand, antioxidant metabolites usually accumulated in fruits and vegetables can provide an effective protection by neutralizing these reactive molecules. Among comestible vegetables, berry fruits are considered one of the richest sources of antioxidant metabolites; hence, they represent a good model for molecular and biochemical investigations about the biosynthesis and the functional role of antioxidants in plants. This review illustrates how recent developments in the fields of genomics and bioinformatics can provide powerful tools to better understand the molecular mechanisms that trigger biosynthesis and accumulation of antioxidant metabolites in berries. [source] | |||||||||||||