Fungi, bacteria, and chemical components in the fermentation process of various maturity levels of drumstick trees (Moringa oleifera Lam.) in making tempeh, a fermented soybean food

This research focuses on the role of fungi and bacterial inhibition on the chemical quality of tempeh made from Horseradish (drumstick trees) tree seeds (Moringa oleifera Lam.) at various levels of maturity. The tempeh produced using these seeds harvested at different maturity stages as treatments before fermentation, namely: B0 = soybeans (control), B1 = mature/old seeds, B2 = medium seeds, and B3 = young seeds, with four replications, composing of totally sixteen test units. There were several stages carried out before the fermentation, namely: soaking, boiling, drying, inoculating, wrapping and then fermenting. In the preparation of yeast (starter culture), a method of Nurrohmah (2013) was applied and modified, while in the preparation of Moringa oleifera, the method of Jubaidah et al. (2016) was adopted and modified. The results showed that Rhizopus sp. could ferment Moringa seeds at all maturity stages. The higher the maturity level of the Moringa seeds, the faster Rhizopus sp. grew and developed, thereby better in inhibiting the growth of bacteria, particularly coliform bacteria. Regarding chemical quality parameters, tempeh made from medium and mature Moringa seeds contained better water (B3 contained 75.73% water), protein (B1 contained 17.21% protein), and fiber (B3 contained 9.39% fiber). Meanwhile, soybeans (B0) contained the highest ash (1.38%), fat (6.41%), and carbohydrate (17.60%) compared to all maturity levels of Moringa seeds.