Nutrition & Food Science
Permanent URI for this communityhttp://hdl.handle.net/1903/2267
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Item Nutraceutical Properties of Low alpha-Linolenic Soybeans Grown in Maryland(2009) Whent, Monica; Yu, Liangli; Food Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Eight soybean genotypes grown in Maryland were analyzed for total phenolic content (TPC), antioxidant capacity, isoflavone composition, lutein content, tocopherol composition, and fatty acid profile. The soybean samples consisted of seven low alpha-linolenic (18:3n-3) experimental lines and one standard cultivar for comparison. 18:3n-3 levels were negatively correlated with oleic acid (18:1n-9). The isoflavones daidzein and genistein were positively correlated with 18:3n-3 levels. Alpha-tocopherol, gamma-tocopherol, and total tocopherols were negatively correlated with 18:3n-3. Two of the reduced 18:3n-3 lines contained significantly higher lutein levels than the ordinary cultivar. All low alpha-linolenic lines contained similar antioxidant capacity to the non-modified genotype. The results of this study show that the Maryland-grown low 18:3n-3 soybeans are sources of antioxidants and isoflavones and may be consumed for health benefits. Specific genotypes may be selected for food production to obtain the most desirable combination of nutritional, nutraceutical, and chemical properties.Item Effects of Post-harvest Treatment and Heat Stress on the Antioxidant Properties of Wheat(2006-08-03) Su, Lan; Yu, Liangli; Food Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)This research examined and compared grain, bran, and micronized bran samples of Ankor and Trego wheat stored at 25, 60 and 100oC for their free radical scavenging properties, total phenolic content (TPC) and phenolic acid compositions. Bran and micronized bran samples stored at 100oC showed decreased TPC and free radical scavenging activities over 9 days of treatment, while there was no significant change observed for grain samples. Because of smaller particle size, micronized bran was more sensitive to heat stress when compared to bran at the two elevated temperatures. In addition, extractable phenolic acids were increased during storage for all kinds of samples on a per dry weight basis. These results demonstrate that whole grain is a preferred form of long-term storage for better antioxidant preservation, and reducing particle size may accelerate the loss of natural antioxidants in wheat bran during storage and heat treatment.Item PHYTOCHEMICAL PROFILES AND ANTIOXIDANT PROPERTIES OF WHEAT(2005-07-28) Zhou, Kequan; Yu, Liangli; Food Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The present study examined and compared wheat grain, bran, aleurone, and micronized aleurone for their antioxidant properties and phytochemical profiles. The results showed that wheat antioxidants were concentrated in bran fraction, particularly in the aleurone layer of wheat bran. Micronized aleurone demonstrated the highest antioxidant activities (scavenging activities against ABTS+, DPPH, ORAC, and chelating activity), and the highest total phenolics and phenolic acids concentration, suggesting that post-harvest treatment may affect the availability of wheat antioxidants. The present +study also investigated bran samples of seven wheat varieties from four different countries for their antioxidant properties and phytochemical profiles. The bran samples exerted enormous differences in concentrations among their phenolic acids, tocopherols and carotenoids. Their antioxidant activities were also notably different from 13% (scavenging capacity against O2-) to 99% (ORAC). These data suggest that wheat varieties and growing conditions might alter wheat antioxidant properties and phytochemical compositions. In addition, eight selected Maryland grown soft wheat varieties or experimental lines were examined for potential beneficial components and antioxidant properties. These soft wheat varieties significantly differed in their ABTS+ scavenging activity and chelating activity. Significant amount of phenolic acids have been demonstrated in all soft wheat grain. But their phenolic acid content markedly differed among different varieties which mainly (89% - 94%) existed as the insoluble bound form with ferulic acid as the predominant phenolic acid. These data suggest the possibility to produce soft wheat varieties rich in selected health beneficial factors for optimum human nutrition through breeding programs. Finally, five phenolic acids commonly present in wheat grain and fractions were examined and compared for their radical scavenging properties and chelating capacities using spectrophotometric and electron spin resonance measurements. These phenolic acids differed in their properties to react with and quench HO, O2-, ABTS+, and DPPH, as well as their capacities to form chelating complexes with transition metals. Strong structure-activity relationships were observed in the present study. Both substitutes on the phenyl ring and the conjugated carbon skeleton may influence the antioxidant properties of these phenolic acids.