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

Tempeh is a fermented product made from soybeans or other types of legumes usingRhizopus oligosporus and Rhizopus oryzae moulds. Soybean contains phenoliccompounds. Phenolic compounds found in soybeans partially act as an antioxidant.Antioxidants are components that are able to inhibit the oxidation process. Soybean alsocontains aflatoxins. Tempeh made from fermented soybeans may indicate to containaflatoxins. This study used a Completely Randomized Design (CRD) with treatments offour soybean types, namely imported “Bola” brand soybean (A1), local Dena 1 typesoybean (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 activityanalysis show that the highest activity is found in Anjasmara tempeh at 38.62±0.22% andthe lowest in Dena 1 tempeh at 29.83±0.12%. The results of the total phenolic analysisshowed that the highest activity is found in Anjasmara tempeh at 16.26±0.29 mg GAE/gextract and the lowest in Dena 1 tempeh at 13.96±0.29 mg GAE/g extract. The results ofaflatoxin 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, whileDevon 1 material was confirmed to contain B1 and B2 types. The lowest aflatoxinconcentration is found in tempeh made from Devon 1 at 2.53 x 10-7 ppb of the B2 aflatoxintype.