Production of a water-soluble protein powder from anchovy and soybean meal by endogenous enzymatic hydrolysis and solid-state fermentation

Abstract

Anchovy (Engraulis japonicus), a small, low-valued, marine fish, and soybean meal (Glycine max), a by-product of soybean oil extraction, are both abundant protein resources (approximately 65 and 46 g per 100 g dry weight, respectively). In this study, water-soluble protein powder from anchovy and soybean meal was obtained by two processes, anchovy endogenous enzymatic hydrolysis (stage 1), and solid-state fermentation of anchovy hydrolysis residue and soybean meal (stage 2). The parameters of hydrolysis stage were optimized with single factor experiments and fermentation stage was optimized using central composite design and validated. Maximum protein recovery (91%) was achieved. The protein was successfully converted into a low molecular weight powder for potential use in supplementation of animal and human diets. Furthermore, anti-nutritional factors mainly composed of 7S, 11S globulin and oligosaccharide in soybean meal were effectively degraded. This work provides a value-added method for novel protein from anchovy and soybean meal. Practical applications: Obtaining protein yields from readily available resource materials is essential in overcoming the protein resource shortage. This work provides a novel technique for the advanced utilization of low-value resources. The product obtained in this study contained abundant peptides, and the amino acid composition, such as the percentage of essential amino acid and flavor amino acid in water-soluble protein was more reasonable than the raw material. The results of this study are suitable for the industrial production of food or feed additive.