Utilization of tofu waste from Indonesian small scale industry as fish feed through a fermentation process

Abstract

Tofu waste is a by-product from the soybean processing industry like tofu and tempeh in Indonesia. The high amount of waste from tofu processing creates problems for the environment, both in aesthetics and odor. Therefore, the utilization and treatment of waste from tofu processing industry activities is needed to reduce the negative impact of the resulting waste. One of them is to use it as a raw material for fish feed. Tofu waste has a good nutrient content (protein content is around 21.3 - 27%), so a potential source of fish raw material. However, tofu waste has low digestibility because of its high fiber (16-23%) and antinutrient substances content. Therefore, improving the quality of tofu waste by fermentation was needed. Fermentation can change a substrate or raw material into the desired product with better quality. It can reduce the levels of crude fiber, increase digestibility, and increase levels of soluble protein and crude protein from raw material. This research aimed to evaluate the quality of tofu waste fermented using Bacillus sp PAS7 as raw material for fish feed production. This research used a completely randomized design (CRD) with four treatments and three replicates. The treatment for determining inoculum doses used concentrations of 0, 2, 4, and 6% per gram (weight) of tofu waste (v / w). The time of the fermentation process was three days at 37oC. The parameters measured were reducing sugar, dissolved protein, proximate analysis, and in vitro protein digestibility. The results showed that tofu waste fermentation using Bacillus sp PAS7 isolate improved the nutrient quality of the material. It can be seen from the increased levels of dissolved glucose and protein, decreased fiber content, and increased in vitro protein digestibility. Fermentation using Bacillus sp PAS7 with a dose of 2% was adequate to improve the quality of tofu waste.