Steaming Process Does Not Affect the Antioxidant Activities of Tempeh Ethanol Extract

Abstract

Tempeh is an Indonesian fermented traditional food made from soybeans. It exhibits antioxidant activities mainly due to phytochemicals known as isoflavones. Since tempeh is mainly consumed cooked, this study investigated the influences of steaming process at three different times (10 min, 30 min and 60 min) on the antioxidant activities of tempeh. While a subtle decrease in antioxidant activities was observed in tempeh aqueous extracts, tempeh ethanol extracts did not differ in antioxidant activities. The results suggested that steaming process, even when applied for an hour, caused very minimal decrease in tempeh antioxidant activities. Such a decrease was particularly observed in the water-soluble fraction but not in the ethanol-soluble fraction. Therefore, steaming could be opted as a good cooking method for tempeh to keep its antioxidant-related health benefits.