| Summary: | 碩士 === 靜宜大學 === 食品營養研究所 === 95 === The objectives of this study were to evaluate the antioxidant activities of tempeh fermented for different days and isolate antioxidant peptides from tempeh. Rhizopus oligosporus was inoculated to soybean Kaohsiung No. 10, and fermented for 0, 1, 2, 5 and 10 days. Lyophilized tempeh powder were extracted with different solvents including hexane, ether, petroleum ether, 95% ethanol and water. Antioxidant activities of different extracts were evaluated with various model systems including DPPH scavenging activity, reducing power, superoxide anion scavenging activity and inhibition of lipid peroxidation. Antioxidant peptides were isolated from water extracts of 10-day fermented tempeh using ultrafiltration, size exclusion chromatography, chromatofocusing chromatography and reverse high performance performance liquid chromatography. The results reveals that the DPPH scavenging effects of all tempeh extracts were superior to unfermented soybean except for water extracts. Although there was no significant difference in the DPPH scavenging activities of water extracts between tempeh and unfermented soybean (p＞0.05), the IC50 value of 10-day fermented tempeh was lower than that of unfermented soybean definitely. Except for water extract from 10-day fermented tempeh, the 95% ethanol and water extracts of tempeh obtained higher reducing power, superoxide anion scavenging activity and inhibition of lipid peroxidation than unfermented soybean. These results indicate that tempeh, microbial fermented soybean, exhibited higher antioxidant activities than soybean. Three antioxidant peptides consisting of 2, 3 or 4 amino acids were isolated from water extract of 10-days fermented tempeh. However, because of the technique limitation on that a single sample contains more than 2 peptides is not able to be sequenced by the Edman degradation, the amino acid sequence of isolated antioxidant peptides are still unknown.
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