Antioxidant activities of the water-soluble fraction in tempeh-like fermented soybean (GABA-tempeh).
Tempeh is a traditional fermented soyfood native to Central Java, Indonesia; tempeh is prepared by salt-free aerobic fermentation using Rhizopus. Similar to miso, tempeh is also reported to be antioxygenic. In this study, we used a tempeh-like fermented soybean. First, soybean was incubated aerobically and then successively incubated anaerobically. Because the gamma-amino butyric acid (GABA) content was increased remarkably, we named this tempeh GABA-tempeh. The contents of other free amino acids and peptides were significantly higher in GABA-tempeh than in conventional tempeh. In this study, we compared the antioxidant activity of the water-soluble fraction in GABA-tempeh with that of soybean and conventional tempeh. The order of the antioxidant activity was shown as follows: GABA-tempeh > conventional tempeh > soybean. The components responsible for the antioxidant activity of GABA-tempeh were isoflavone aglycones, free amino acids, and peptides, which increased during aerobic and anaerobic fermentations.
Watanabe
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Department of Food Science and Nutrition, Faculty of Human Ecology, Showa Women's University, 1-7-57 Taishido, Setagaya, Tokyo, Japan. nakamich@swu.ac.jp
Fujimoto
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K
Aoki
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H
D000596:Amino Acids / Q000032:analysis; D000975:Antioxidants / Q000032:analysis*; D005285:Fermentation; D005524:Food Technology / Q000379:methods*; D007214:Indonesia; D007529:Isoflavones / Q000032:analysis; D010455:Peptides / Q000032:analysis; D012233:Rhizopus; D045730:Soy Foods / Q000032:analysis*; D013025:Glycine max; D005680:gamma-Aminobutyric Acid / Q000032:analysis
D000596:Amino Acids; D000975:Antioxidants; D007529:Isoflavones; D010455:Peptides; D005680:gamma-Aminobutyric Acid