The Effects of Duration of Fermentation on Total Phenolic Content, Antioxidant Activity, and Isoflavones of The Germinated Jack Bean Tempeh (Canavalia Ensiformis)

The daily consumption pattern of people in Indonesia is very close to the consumption of side dishes derived from legumes, especially those consumed in the form of tempeh food products. The purpose of this study was to determine the content of total phenolic compounds, flavonoids, antioxidant activity and isoflavone content of germinated jackbean tempeh with a fermentation duration of 0–5 days. Isoflavone extract was obtained by the extraction method using 70% alcohol. The total content of phenolic compounds was measured by the method of Folin ciocalteau, antioxidant activity was measured with DPPH and isoflavone content was determined using High Performance Liquid Chromatography (HPLC). The total content of phenolic compounds (TPC), antioxidant activity and isoflavone was analyzed using the ANOVA assay and differences between treatments compared to the Smallest Real Difference test with a meaningfulness level of 5%. The total phenolic compound content and the highest antioxidant activity during the tempeh fermentation process were obtained on the 5th day fermentation period of 10.70±0.31 (mg. GAE/g) for total phenolic and 457.04±151.91(%) for IC50 values with intergroup test results showed significant differences. The highest isoflavone deposits were also obtained at day 5 tempeh fermentation duration for all isoflavones i.e. daidzein, glycitein, genistein and factor-2 and there were significant differences between treatment groups. The isoflavone content was 4.6341±1.7431 mg/kg for daidzein, 5.4483±2.2936 mg/kg for glycitein, 0.9236±0.3288 mg/kg for genistein and 0.458±0.209 for factor-2. This study shows that the germination and fermentation process of tempeh causes changes in the content of total phenolic compounds and antioxidant activity as well as increasing and influencing the isoflavone profile.