Optimization of production parameters for preparation of natto-pigeon pea with immobilized Bacillus natto and sensory evaluations of the product

In the present investigation, the production parameters for the preparation of natto-pigeon pea with immobilized Bacillus natto were optimized and its sensory evaluations were analyzed. The optimal immobilization conditions for Bacillus natto were as follows: alginate concentration 7%, CaCl2 concentration 2.5%, concentration of bacteria 7.4 log cfu/mL and alginate bead diameter 5.0mm. Fermentation parameters of natto-pigeon pea were optimized by single-factor experiments and central composite design with the index of fibrinolytic activity. The fibrinolytic activity of natto-pigeon pea reached 1895.05±0.24IU/g under the optimal conditions: wet weight of beads with Bacillus natto 0.8g/g material, ratio of liquid to solid 15: 1mL/g, pH6.5, temperature 38°C and time 48h. Moreover, the sensory evaluations of the natto-pigeon pea were superior to that of natto-soybean because of the advantages of pigeon pea on fermentation. Sensory results indicated that the method was an accepted procedure for the production of natto-pigeon pea.