Evaluation of thermo-mechanical and microbial-facilitated processing on the chemical composition of soybean meal

Abstract

A laboratory experiment was conducted to examine the effects of microbial fermentation using Bacillus subtilis and Aspergillus oryzae on the chemical composition of a commercial soybean meal (SBM). Five quadruplicate samples of SBM were subjected to four treatments with one batch serves as a control. The treatments were steam conditioning treatment (P1) where the other three groups were further fermented with B. subtilis (P2), A. oryzae (P3), and the combination of B. subtilis + A. oryzae (P4). The results showed that bacterial and fungal inoculation increased crude protein (CP) content when compared to control (p<0.05). In addition, fiber fractions including neutral detergent fiber (NDF) and acid detergent fiber (ADF) were concomitantly decreased with fermentation (p<0.05). In this study, no significant difference was observed on CP and NDF content with heating treatment (P1, p>0.05). However, this treatment decreased ADF content (p<0.05). Ether extract (EE), ash, non-fibrous carbohydrates (NFC), and total phosphorus contents were not affected by the treatments. To conclude, fermentation either with bacterial or fungal inoculants was effective to improve the chemical composition of SBM as indicated by increasing CP and decreasing fiber contents of SBM.