The Influence of Germination on Macronutrient Composition and Isoflavones Profile in Boiled Fermented Grobogan Soybean (Tempe)

High temperature treatment and fermentation are two major preparation methods applied by consumers to make soybean more edible. Germination is a simple way to induce certain bioactive compounds in soybeans. Objective: This study aimed to determine the impact of germination on macronutrient compositions and isoflavones’ level in boiled tempe. Method: Grobogan soybean samples were sprouted at room temperature before the fermentation. The samples were fermented using 0.2% and 0.4% inoculum contained Rhizopus oligosporus before the boiling process. Fat, protein, and carbohydrate compositions were estimated by the soxhlet extraction, the Kjeldahl method, and spectrophotometric respectively. Genistein and daidzein contents in the samples were analysed by high-performance liquid chromatography (HPLC). Result: In comparison with ungerminated Grobogan tempe samples, based on dry weight, the germinated Grobogan tempe samples described a significant reduction in protein (24-hour germination period, p=0.002) and carbohydrate (24-hour and 48-hour germination periods, p