Antioxidant activity, total phenolic, and aflatoxin contamination in tempeh made from assorted soybeans (Glycine max l merill)

Abstract

Tempeh is a fermented product made from soybeans or other types of legumes using Rhizopus oligosporus and Rhizopus oryzae moulds. Soybean contains phenolic compounds. Phenolic compounds found in soybeans partially act as an antioxidant. Antioxidants are components that are able to inhibit the oxidation process. Soybean also contains aflatoxins. Tempeh made from fermented soybeans may indicate to contain aflatoxins. This study used a Completely Randomized Design (CRD) with treatments of four soybean types, namely imported “Bola” brand soybean (A1), local Dena 1 type soybean (A2), local Devon 1 type soybean (A3), and local Anjasmara type soybean (A4). Each treatment was repeated three times. Analyses carried out include antioxidant activity, total phenolic compounds and aflatoxin contamination. The results of antioxidant activity analysis show that the highest activity is found in Anjasmara tempeh at 38.62±0.22% and the lowest in Dena 1 tempeh at 29.83±0.12%. The results of the total phenolic analysis showed that the highest activity is found in Anjasmara tempeh at 16.26±0.29 mg GAE/g extract and the lowest in Dena 1 tempeh at 13.96±0.29 mg GAE/g extract. The results of aflatoxin analysis, using the LC-MS/MS method confirmed that tempeh raw materials (USA-imported, Dena 1, and Anjasmara) contain aflatoxin of B1, B2 and G1 types, while Devon 1 material was confirmed to contain B1 and B2 types. The lowest aflatoxin concentration is found in tempeh made from Devon 1 at 2.53 x 10-7 ppb of the B2 aflatoxin type.