Nutrition & Food Science
Permanent URI for this communityhttp://hdl.handle.net/1903/2267
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Item Promoting the production and consumption of wheat-based functional foods rich in antioxidants.(2008-11-20) Luther, Marla West; Yu, Liangli; Food Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The present study evaluated the effects of solid state yeast treatment and thermal processing on the extractability and in-vitro bioavailability of antioxidants from wheat bran and whole-wheat pizza crusts, and developed sample outreach materials for promoting the consumption of whole-wheat functional foods. The first section analyzed the effect of solid-state yeast treatment on the extractable antioxidant properties of wheat bran. Wheat bran was treated with ten commercially available food grade yeasts under solid state conditions. Antioxidant properties were evaluated by measuring total phenolic content, and radical scavenging capacities against the cation ABTS, peroxyl (ORAC), DPPH (RDCS), and hydroxyl (HOSC) radicals. Results showed that under the selected conditions, yeast strain LBE.11 was able to increase ORAC and HOSC radical scavenging by 50% and 67%, respectively. The second part of this study evaluated the impact of bran particle size, fermentation time, and baking time and temperature on the 100% ethanol extractable antioxidant capacities of whole wheat pizza crust. Results showed that pizza crusts produced with reduced bran particle size maintained antioxidant capacity throughout thermal processing. At 18 hrs of fermentation RDSC and TPC values of the pizza crusts were increased by 17% and 23%, respectively. Increasing baking temperature increased RDSC values by 14 and 17% for pizza crusts prepared with Lakin and Trego variety wheat, respectively. The third part of this study analyzed the in-vitro bioavailability of wheat antioxidants in baked pizza crusts. Antioxidant properties were evaluated by measuring total phenolic content, and radical scavenging capacities against the cation ABTS, peroxyl (ORAC), DPPH (RDCS), and hydroxyl (HOSC) radicals. Pizza crusts with higher available antioxidants may have a greater level of bio-available antioxidants. The final segment of this research was to develop a tri-fold for promoting the consumption of whole wheat foods. The tri-fold was designed to include food-specific knowledge, consumption consequences knowledge in addition to recipes and directions, and nutritional facts. Integrating research findings into outreach materials may be an effective way to increase functional food consumption. Results from these studies indicate that there are numerous ways to increase antioxidant levels in the diet.Item Enhancing the availability of natural antioxidants in wheat-based food ingredients and food products through improved post-harvest treatments and processing conditions(2007-04-20) Moore, Jeffrey Calvin; Yu, Liangli; Food Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Wheat grain has significant antioxidant contents concentrated in the bran fraction, most of which may not be bioavailable in humans because they are not released from matrix materials during digestion. The present study developed solid-state enzymatic and yeast post-harvest treatments, and investigated the effects of these treatments and food processing on the extractable antioxidant properties of whole-wheat based food ingredients and food products. Antioxidant properties investigated in this study included scavenging capacities against cation ABTS radicals, peroxyl radicals (ORAC), hydroxyl radicals, and DPPH radicals, and total phenolic contents and phenolic acid compositions. The first part of this research developed and validated a high-throughput fluorometric hydroxyl radical scavenging capacity (HOSC) assay. The HOSC assay utilized a Fe(III)/H2O2 Fenton-like reaction to generate hydroxyl radicals, fluorescein as detector probe, trolox as an antioxidant standard, and area under the curve measurements to quantify scavenging capacity. The hydroxyl radical purity and potential solvent interference in the assay system were evaluated using electron spin resonance. The HOSC assay was found to have acceptable performance characteristics including linear range, accuracy, and reproducibility. The second part of this study investigated the potential of solid-state enzyme and yeast treatments to improve wheat bran antioxidant properties. Both enzyme and yeast treatments were capable of increasing available wheat bran antioxidant properties. Reaction parameters found to influence the effectiveness of these treatments to enhance wheat bran antioxidant properties included enzyme preparation and reaction moisture content for enzyme treatments, and yeast preparation along with dose and treatment time for yeast treatments. The final part of this research evaluated the effects of processing conditions including bran particle size, fermentation time, and baking conditions on the antioxidant properties of a whole-wheat pizza crust. Baking increased extractable antioxidant properties up to 82%. Fermentation time caused some significant increases, while bran particle size had no influence on extractable whole-wheat pizza crust antioxidant properties. This study suggests that post-harvest treatment of wheat bran and optimized processing conditions for whole-wheat food products are potential approaches for increasing their extractable antioxidant properties.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.