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The antioxidant properties of methanolic extracts from soybean obtained with germination, wounding, and application of biotic elicitors were evaluated. Also, the relationship between observed antioxidant properties and compositional changes in isoflavone content was determined. The 2 biotic elicitors used in this study were the food-grade fungus Aspergillus sojae and A. sojae cell wall extract. Isoflavone content was determined by C18 reverse phase high-performance chromatography coupled with a photodiode array detector. Antioxidant activities of the extracts were measured using 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging and β-carotene cooxidation in a linoleate system. Higher antioxidant activities were observed in wounded and elicitor-treated extracts when compared with nonwounded control extracts. In addition, the phenolic content was higher in extracts from wounded and elicitor-treated soybean. Germination for 3 d slightly decreased total isoflavone content (–4.3%); however, wounding increased total isoflavone content (25.8%). The soybean extracts from seeds treated with A. sojae biotic elicitors had the highest total isoflavone contents (9.8 to 11.6 mg/g extract) and displayed the highest antioxidant activities in both the DPPH and β-carotene assays. Also identified in the wounded and elicitor-treated extracts were the induced isoflavones glyceollins that contributed to the higher isoflavone contents observed. [ABSTRACT FROM AUTHOR]

The article presents a study on the antioxidant properties of methanolic extracts of rice ingredients and other selected plant seeds including corn, soybean and cotton seed, and the effects on lipid oxidation into beef patties. It notes the benefit of antioxidants in food storage, preventing rancidity of food due to lipid oxidation which negatively affects the food's flavor, nutritional quality and safety. It finds that methanolic extracts of milled-rice co-products are effective antioxidants.