Physicochemical and Antioxidant Properties of Germinated Soybean Tempe after Two Days Additional Fermentation Time

Abstract

Tempe contains antioxidant components, which will increase if the soybean is germinated. Tempe is usually consumed in the fresh form two days after the fermentation process, even though its antioxidant level is higher after extending for 2 days. This study aimed to evaluate the changes in physicochemical and antioxidant properties of germinated soy tempe due to 2-days additional fermentation time. The six samples from germination (germinated and non-germinated soybean) and additional fermentation time (0, 1, and 2 days) treatments were analyzed for their physicochemical (sensory, texture, color, acidity, proximate content) and antioxidant components (antioxidant capacity, total free phenolic compound, and isoflavones). The results showed the decline in sensory properties of tempe due to additional fermentation time, but this food was still worth eating, without any "dislike" score overall. The decline was linear with the decrease in texture and increase in pH. The proximate content, color, and water activity experienced no changes. Meanwhile, antioxidant components increased during the additional fermentation time. The effects of soybean germination on antioxidant components were not dominant, except for isoflavones. In conclusion, the additional fermentation time only slightly decreased the sensory quality without changing the proximate composition with an increase in the antioxidant properties.