米曲霉1228制曲条件的优化及酱油酿造的研究

以米曲霉1228为发酵菌种,豆粕和麸皮为原料制曲,通过单因素试验和正交试验,优化制曲工艺条件;采用低盐固态发酵工艺,进行酱油酿造试验。结果表明:豆粕与麸皮以6:4配比,采用90%加水量和0.5%接种量制曲32 h,成曲的中性蛋白酶酶活为1473 U/g;发酵20 d后,测得酱油的氨基酸态氮含量为6.90 mg/mL,可溶性无盐固形物含量为163.60 mg/mL,酱油色泽棕红,酱香浓郁。

Optimization Conditions of Koji Making by Aspergillus oryzae 1228 and Study on Soy Sauce Brewing

Using soya bean meal and wheat bran as material, Aspergillus oryzae 1228 was selected for koji making. By single factor test and orthogonal experiment, the optimum processing conditions of koji making were obtained. The brewing experiment of soy sauce was conducted by low-salt solid- state fermentation. The best conditions were as follows: soya bean meal to wheat bran ratio 6:4, water content 90%, inoculating scale 0.5% and koji making for 32 h. Under the optimized conditions, the neutral protease activity in koji was 1473 U/g. After 20 days for fermentation, the contents of amino acid nitrogen and soluble saltless solid were 6.90 mg/mL and 163.60 mg/mL respectively in the soy sauce. The soy sauce showed good flavor and color.