Effects of Combined Pure Cultures of Rhizopus sp. (Rhizopus oryzae, Rhizopus oligosporus, and Rhizopus stolonifer) on Tempeh Extract Yogurt as a Functional Food

Background Tempeh Extract Yogurt offers an alternative to raw tempeh in a new method for developing yogurt that can be used as a functional product to benefit human health. This study aimed to determine the functional food potential of yogurt made with tempeh extract combined with the use of mixed cultures of Rhizopus and lactic acid bacteria. Methods This method evaluated five specific ratios of three Rhizopus species for making tempeh, including Rhizopus oryzae, Rhizopus oligosporus, Rhizopus stolonifer inoculums of 1:1:1, 1:2:1, 2:1:2, 1:1:2, and 2:1:1. RAPRIMA tempeh starter was used as a control group, fermented with Lactic Acid Bacteria to produce tempeh extract yogurt. Results Tempeh extract yogurt has characteristics determined by the Indonesian National standard (SNI 2891:2009) such as thick liquid, specific aroma, sour taste, and homogeneous consistency. The highest content of vitamin B-12 and folate in tempeh extract yogurt was at a 1:2:1 ratio (0.072 g/100 mL and 0.059 g/100 mL), and the genistein isoflavone in RAPRIMA was 3.669 g/100 mL with a pH value of 4.2 and a total bacterial content of 14,3 x 10(8) CFU/mL. Conclusion Tempeh extract yogurt contains several beneficial characteristics, including vitamin B-12, folate, isoflavones, and total bacteria. Therefore, tempeh extract yogurt is available as a healthy, functional food.