Enhancement of soluble protein, polypeptide production and functional properties of heat-denatured soybean meal by fermentation of Monascus purpureus 04093

The aim of this study was to investigate the effect of fermentation parameters on heat-denatured soybean meal by Monascus purpureus 04093 on the soluble protein and polypeptide production and to evaluate the antioxidant activity and functional properties of the fermented products. The optimal fermentation parameters were obtained as follows: 11.25% soybean meal loaded in a 80 g/500 mL flask with 0.02 g/L Na2SO4 at 28°C and pH 6.5 for 96 h. The soluble protein and polypeptide yield reached 290.9 ± 3.4 mg/g and 106.6 ± 0.9 mg/g, respectively, which was 3.25 and 12.25 times that of the control, respectively. Moreover, the polysaccharide and amino acid contents, the antioxidant activities, the emulsifying properties and foaming capacities were significantly enhanced by Monascus fermentation (P < 0.05). The results indicated the viability of soybean meal in combination with Monascus for producing proteins with desirable characteristics as functional ingredients utilized in the food industry.