Characterization of isoflavone bioactive compounds and antioxidant activity test of ethanol extract of tempe made from Glycine soja, Lablab purpureus, and Phaseolus lunatus

Abstract

Sulistiani HR, Handayani S, Pangastuti A. 2012. Characterization of isoflavone bioactive compounds and antioxidant activity test of ethanol extract of tempe made from Glycine soja, Lablab purpureus, and Phaseolus lunatus. Biofarmasi 14: 62-72. The aim of this research was: (i) finding out the content of the isoflavone compounds of daidzein, genistein, glisitein, and factor-2, (ii) conducting the test of antioxidant activity of the tempeh made of black soybean, hyacinth bean, and lima bean with the variations of length of fermentation (0,1,2, 3, 4 day(s)), and (iii) comparing the antioxidant activity of the black soybean, hyacinth bean, and lima bean and their tempeh product with both the ethanol extract of the yellow soybean and its tempeh product and several natural antioxidants (α- tocoferol, ß carotene, ascorbic acid) and BHT synthetic antioxidant. The materials used for the research were black soybean, hyacinth bean, and lima bean with the variations of seed measure (whole seed and chopped seed) and length of fermentation (0,1,2, 3, 4 day(s)). The method used to extract the isoflavone compounds was maceration, and the method used to identify the isoflavone compounds was that of HPLC. The test of antioxidant activity used the method of DPPH. The calculation of the antioxidant activity used the computer program of SPSS, Version 15. General Model – Univariate and One Way – Anova. The results of the research showed that both the whole black soybean and hyacinth bean genistein, while the whole lima bean contained daidzein. The largest total contents of isoflavone were in the 2-day fermentation of the black soybean, in the 1-day fermentation of the hyacinth bean, in the 3-day fermentation of the lima bean, and in the 2-day fermentation of the yellow soybean. The highest antioxidant activity in the 3-day fermentation of the black soybean, hyacinth bean, lima bean, and yellow soybean; the black soybean highest antioxidant activity compared to other compounds such as ß-carotene, α- tocopherol, vitamin C, and BHT synthetic antioxidant. Thus, the black soybean and its tempeh product fermented for three days were potential to be used as a natural antioxidant.