Enzymolysis of Fermented Corn Meal to Prepare Natural Umami Flavoring

In this study, corn meal was fermented by Corynebacterium glutamicum to produce a new natural flavoring materia. Firstly, the enzymatic hydrolysis process of corn meal was optimized by single factor experiment and orthogonal experiment. Then, the fermentation conditions of C. glutamicum GL-6 were optimized at shaking flask level to determine the best nitrogen source and content and the best addition amount of corn meal enzymolysis solution. Then verification was carried out at the level of 20 L fermenter. 5% Maltodextrin was added into the supernatant of fermentation broth and spray dried to obtain the umami sample. Finally, the composition of the sample was detected and evaluated. The results showed that the optimal enzymatic hydrolysis conditions were solid-liquid ratio 1:4, enzyme dosage 1%, temperature 90 ℃, time 3 h, under which the enzymatic hydrolysis degree DE value reached 60.84%. The optimal nitrogen source for glutamate production by C. glutamicum GL-6 fermentation was yeast extract FIG12LS 30 g/L, and the optimal addition amount of corn meal hydrolysate was 50%（v/v）. The content of MJ glutamate was 43.9 g/100 g, and the total content of amino acid was 44.8 g/100 g, which increased by 24.0% and 23.4%, respectively, compared with that of CK without corn meal enzymolysis fermentation. In addition, sample MJ was rich in nutty and coffee-flavored pyrazines. Compared with sample CK, its umami content and nutritional value were improved, and its flavor was richer. This study provides a new idea for the production of umami flavoring by fermentation of natural plant materials and improves the market competitiveness of the product.