黑纳豆固态发酵工艺优化的研究

纳豆是大豆经蒸煮后接种纳豆芽孢杆菌发酵而得到的一种微生态健康食品。纳豆不仅含有丰富的营养物质,而且具有预防和治疗“三高”、心血管疾病的功效。但是传统纳豆口感一般,在我国不受消费者喜爱。文章以优质的黑色大豆为原料,对黑豆纳豆的发酵工艺进行优化,对纳豆品质进行改良。该研究以纳豆激酶纤溶活性和感官评价为指标进行单因素试验,探究各种因素对纳豆品质的影响情况,选取对发酵工艺影响最大的4个因素,利用正交法对发酵条件进行优化。最终确定浸泡15 h,蒸煮30 min,纳豆菌接种量4%,37℃发酵18 h为最优的发酵条件。优化后的黑纳豆没有了难闻的氨味,豆粒饱满,有光泽,口感软糯且纳豆激酶纤溶酶活达到6116.67 U/mg。

Study on Optimization of Solid-state Fermentation Technology of Black Natto

Natto is a kind of microecological healthy food produced by fermentation of Bacillus natto after stewing.Natto is not only rich in nutrients,but also has the effect of preventing and treating cardiovascular diseases such as“three highs”.However,the taste of traditional natto is general,and is not popular with the consumers in China.In this paper,high-quality black soybeans are used as the raw materials,and the fermentation process of natto is optimized,the quality of natto is improved.In this study,the fibrinolytic activity of nattokinase and sensory evaluation are used as the indicators to conduct single-factor experiments to explore the effects of various factors on the quality of nattokinase.Four factors with the greatest impact on fermentation technology are selected to optimize the fermentation conditions by orthogonal experimental method.Finally,it is determined that the optimum fermentation conditions are the soaking time of 15 hours,the cooking time of 30 minutes,the inoculum amount of Bacillus natto of 4%,the fermentation temperature of 37℃and the fermentation time of 18 hours.The optimized black natto has no unpleasant ammonia odour,and the grains are plump,shiny,soft and the fibrinolytic activity of nattokinase reaches 6116.67 U/mg.