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Compound Contents (compound + content)
Selected AbstractsPHENOLIC COMPOUND CONTENT, ANTIOXIDANT AND RADICAL-SCAVENGING PROPERTIES OF METHANOLIC EXTRACTS FROM THE SEED COAT OF CERTAIN THAI TAMARIND CULTIVARSJOURNAL OF FOOD BIOCHEMISTRY, Issue 5 2010MANEEWAN SUKSOMTIP Methanolic extracts from the seed coats of five major tamarinds (Srichomphu, Sithong-nak, Sithong-bao, Priao-yak and Khanti) cultivated in Thailand were investigated for their content of phenolic compounds and their antioxidative properties. Antioxidative properties were evaluated by various different methods: scavenging effect on the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl radical, anti-lipid peroxidation and reducing power assay. The phenolic compound contents were determined by spectrophotometric methods. Extract of Priao-yak with the highest tannin content showed the strongest reducing power, while extract of Khanti with the highest proanthocyanidin content revealed high scavenging ability on both DPPH and hydroxyl radicals. Stronger antioxidative activity measured by most assays was noted for the extract of Sithong-bao with a high content of total phenols, proanthocyanidin and tannins. The results suggest that specific phenolic constituents in the extract could be responsible for the different antioxidant properties observed in different cultivars. Furthermore, seed coat extract of Sithong-bao may be a potential source of natural antioxidant to be developed into nutraceuticals. PRACTICAL APPLICATIONS Components of Tamarindus indica L., a tree indigenous to India and South-East Asia, have long been used as a spice, food component and traditional medicine. According To traditional medicine, the tamarind pulp is used as a digestive, carminative, laxative, expectorant and blood tonic; the seeds are used as an anthelmintic, antidiarrheal and emetic. In addition, the seed coat is used to treat burns and aid wound healing as well as as an antidysenteric. Recent studies have demonstrated polyphenolic constituents with more potent antioxidant and anti-inflammatory activities of T. indica seed coat extract. Therefore, seed coat extracts of T. indica have economic potential for development into health promotion products as well as natural preservatives to increase the shelf life of food by preventing lipid peroxidation. [source] EFFECT OF STORAGE TEMPERATURE AND TIME ON QUALITY IN MINIMALLY PROCESSED LITCHI FRUIT (LITCHI CHINENSIS SONN.)JOURNAL OF FOOD QUALITY, Issue 3 2010ELIA NORA AQUINO BOLAÑOS ABSTRACT Rind browning is the most serious marketing problem for litchi (Litchi chinensis Sonn.) fruit, although it has no effect on the quality of the edible aril portion. Physicochemical, biochemical and subjective quality evaluations were done in minimally processed (peeled and vacuum-packed) litchi cv. Racimo Rojo fruit stored 18 days at 2, 5 or 10C. Little change was observed in total soluble solids, titratable acidity and pH, independent of storage temperature. Polyphenol oxidase (PPO) activity decreased, total phenolic compound content remained unchanged and peroxidase (POD) activity increased during storage. Correlation was low (<0.63) between color parameters (L*, a*and b*) and PPO and POD activities, and phenolic compounds. The minimally processed fruit stored at 2C exhibited characteristics similar to fresh fruit, whereas those stored at 5 and 10C emitted disagreeable odors that lowered their subjective quality. PRACTICAL APPLICATIONS The insignificant physicochemical changes observed here suggest that when stored at 2C, litchi fruit can be offered as a minimally processed product with characteristics similar to fresh fruit. Unlike most other minimally processed fruit products and other litchi varieties, pulp browning was not a significant problem in litchi cv. Racimo Rojo after peeling, providing it a potential commercial advantage. [source] Improving Grape Quality Using Microwave Vacuum Drying Associated with Temperature ControlJOURNAL OF FOOD SCIENCE, Issue 1 2007C. D. Clary ABSTRACT:, Microwave (MW) vacuum dehydration using temperature to control the level of MW power demonstrated potential in improving the performance of the process. Product surface temperature measured by an infrared temperature sensor was used to control MW power at any level between 0 and 3 kW. Multiple linear regression analysis indicated an r2= 0.942 for prediction of final moisture content and r2= 0.985 for prediction of puffed character of grapes based on product temperature, time, specific energy, fresh fruit sugar, and fresh fruit moisture content. Temperature was found to be the most significant predictor. The elemental and compound contents of grapes dried using MW vacuum was compared to sun-dried raisins. The grapes dried using MW vacuum exhibited better preservation. Vitamin A was found in the MW-vacuum-dried grapes but none was detected in the raisins, and Vitamin C, thiamine, and riboflavin were also higher in the MW-vacuum-dried grapes than in the raisins. [source] Antioxidant and antimicrobial activities of Polygonum cognatum Meissn extractsJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 1 2003Ali Y Abstract The antioxidant activities, reducing powers, 2,2-diphenyl-l-picrylhydrazyl (DPPH) radical-scavenging activities, total phenolic compound contents and antimicrobial activities of ether, ethanol and hot water extracts of Polygonum cognatum Meissn were studied in vitro. The highest antioxidant activity was found in the water extract. However, there were no statistically significant differences among 15,µg,ml,1 extract-containing samples in linoleic acid emulsion (0.02,M, pH 7.0) during 120,h of incubation (P,>,0.05). The reducing power of the water extract was the highest, but its reducing power was markedly lower than that of ascorbic acid. The highest DPPH radical-scavenging activity was found in the water extract, with 50% DPPH radical scavenging at a concentration of 100,µg,ml,1 dried water extract, while at the same concentration of dried ethanol extract the value was 12%. Surprisingly, no DPPH radical-scavenging activity was observed in the ether extract. The concentrations of phenolic compounds found were 0.48, 0.50 and 0.01,µg,ml,1 gallic acid equivalent in 10,µg,ml,1 water, ethanol and ether extracts respectively. The ether and ethanol extracts showed antimicrobial activity against Staphylococcus aureus and Bacillus subtilis. The water extract did not show antimicrobial activity against the studied micro-organisms. © 2002 Society of Chemical Industry [source] Loss of tocopherols and formation of degradation compounds at frying temperatures in oils differing in degree of unsaturation and natural antioxidant contentJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 14 2002Daniel Barrera-Arellano Abstract Samples of oils of different degrees of unsaturation, namely palm olein, olive oil, high-linoleic sunflower oil, high-oleic sunflower oil, rapeseed oil and soybean oil, were heated at 180,°C for 2, 4, 6, 8 and 10,h in the presence or absence of their natural antioxidants. Also, tocopherol-stripped oils were supplemented with ,-tocopherol (500,mg,kg,1), ,-tocopherol (500,mg,kg,1) or a mixture of ,-, ,-, ,- and ,-tocopherols (250,mg,kg,1 each) and heated under the same conditions. Losses of tocopherols and formation of polymeric triacylglycerols were followed. Total polar compounds were also evaluated after 10,h of heating. Results demonstrated that tocopherols were lost very rapidly, in the expected order, with ,-tocopherol being the least stable. Polymeric and polar compound formation during heating was inhibited to a variable extent, being more dependent on the natural content and type of tocopherols than on the degree of unsaturation of the oil. For example, polymeric and polar compound contents in soybean oil were significantly lower than those found in high-linoleic sunflower oil. However, the expected influence of the degree of unsaturation was evident when oils were unprotected or possessed identical initial antioxidant contents. Finally, levels of degradation compounds after 10,h of heating were not dependent on the remaining content of antioxidants. © 2002 Society of Chemical Industry [source] | ||||||||||