Abstract:

This study aims to optimize the fermentation process for preparing fermented feed from Huangjiu lees. Through single-factor experiments, using small peptides and lactic acid as primary fermentation products, the optimal feed-to-water ratio, microbial inoculum volume, microbial inoculum ratio, and fermentation time were determined. A three-factor three-level orthogonal experiment was conducted to investigate the effects of feed-to-water ratio, microbial inoculum volume, and fermentation time on small peptide and lactic acid contents in fermented products. The results of single-factor analysis showed that adding 5% molasses significantly enhanced small peptide contents, with optimal parameters being feed-to-water ratio of 1∶0.4, microbial inoculum volume of 1.0%, microbial inoculum ratio of 1∶1∶1, and fermentation time for 6 d. The orthogonal experiment demonstrated that the highest small peptide content of 119.11 mg·g^-1 and lactic acid content of 0.53 g·kg^-1 were achieved under feed-to-water ratio of 1∶0.4, microbial inoculum volume of 1.5%, and fermentation time for 5 d. The optimized fermentation process was determined as 80% Huangjiu lees, 20% wheat bran, 5% molasses, feed-to-water ratio of 1∶0.4, microbial inoculum volume of 1.5%, microbial inoculum ratio of 1∶1∶1, and fermentation time for 5 d.

Key words: Huangjiu lees, solid-state fermentation, fermentation process, orthogonal experiment