纳豆芽孢杆菌(Bacillus natto)发酵鱿鱼碎肉的工艺优化

Optimization of Fermentation Conditions of Minced Squid Meat by Bacillus natto

为进一步提高鱿鱼碎肉的利用价值,本实验以鱿鱼碎肉作为纳豆芽孢杆菌发酵基质,研究料液比、葡萄糖添加量、发酵pH值、发酵时间和发酵温度对鱿鱼碎肉发酵效果的影响。在以单因素试验确定发酵时间72 h和发酵温度37℃的条件后,再对料液比、发酵pH值和加糖量进行三因素三水平的Box-Behnken响应面试验分析,以发酵液的氨基态氮含量为响应值,得到纳豆芽孢杆菌发酵鱿鱼碎肉最佳条件为:料液比1:1.2(m/V)、发酵pH 8.8和加糖量3.13%。在最优发酵条件下,鱿鱼碎肉发酵液的氨基态氮实际含量达到2.457 mg/mL。氨基酸分析结果显示鱿鱼碎肉发酵液富含具有鲜味和甜味特征的谷氨酸(84.141 mg/g)、天冬氨酸(49.480 mg/g)和甘氨酸(49.425 mg/g),达到氨基酸总量的39.05%。必需氨基酸总量为149.320 mg/g,占氨基酸总量的31.86%。Sephadex G25凝胶过滤层析显示鱿鱼碎肉纳豆芽孢杆菌发酵液由多肽、小肽及游离氨基酸组成。

In the present study,minced squid meat was used as the fermentation substrate for Bacillus natto to improve the application value of squid minced meat.The effects of liquid-solid ratio（1：2-1：5）,glucose concentration（0.5%-3.5%）,initial pH（6.0-9.0）,fermentation time（24-96 h） and fermentation temperature（27-42℃） on the amino nitrogen content of fermented broth were evaluated.Using one-factor-at-a-time method,the fermentation time and temperature were selected as 72 h and 37 ℃,respectively.Subsequently,three variables including solid to liquid ratio（m/V）,initial pH and glucose concentration were optimized by response surface methodology based on Box-Behnken design using the amino nitrogen content of fermented broth as the response.The optimal conditions for solid to liquid ratio,initial pH and glucose concentration were determined as 1：1.2,8.8 and 3.13%,respectively.Experiments carried out under these conditions led to an amino nitrogen content of 2.457 mg/mL.Moreover,amino acid composition analysis demonstrated that the fermented squid minced meat was rich in glutamic acid（84.141 mg/g）,aspartic acid（49.480 mg/g） and glycine（49.425 mg/g）.These amino acids were responsible for umami and sweet taste characteristics with total content of 39.05%.The total essential amino acid concentration was 149.320 mg/g,accounting for 31.86%of all determined amino acids.In addition,the relative molecular weight distribution indicated that the fermented squid minced meat was composed of polypeptides,small peptides and free amino acids.