粗酶水解全脂豆粉提取油脂和蛋白

Oil and protein simultaneously extracted from soybean using crude enzyme produced by microbial fermentation

水酶法提取大豆油和蛋白是一项可替代溶剂浸提制油工艺的绿色环保技术,但是商品酶的价格较高且酶活易受外界环境影响,使水酶法制油技术的应用受到限制。该试验在优化过的培养基中接种枯草芽孢杆菌发酵培养42h,所得发酵液经测定含有碱性和中性两种蛋白酶,所得粗酶经透析浓缩后,在碱性蛋白酶活为(2000±200)U/mL,中性蛋白酶活为(1500±200)U/mL时,在酶液中接入挤压膨化豆粉水解。通过对酶解条件的优化,试验证实在温度55℃,料液比1∶8g/mL,起始pH值为10的条件下水解6h,总油提取率有最大值,达到了94.2%,总蛋白提取率为90.1%,跟商品Alcalase碱性蛋白酶提取相比,总油提取率增加了1.9%,总蛋白提取率降低了2%。通过对粗酶和商品Alcalase酶水解豆粉过程产生的乳状液破乳后油的品质分析,发现二者所得油的性能指标没有明显区别,品质均优于浸提法制油,粗酶提取的水解蛋白比用Alcalase碱性蛋白酶水解的分子量更小,范围分布更广。

Enzyme-assisted aqueous extraction processing （EAEP） is an environmentally friendly alternative technology to hexane extraction of soybean oil,EAEP has significant challenges, however, that must be overcome before becoming practical： the high price of enzyme, activity is influenced significantly by conditions, which has discouraged industrial adoption of EAEP. In this study Bacillus subtilis was inoculated into the optimal medium and fermented for 42 h, it was found that the broth contained alkaline and neutral protease. Extruded full fat soybean flour was hydrolyzed by the crude enzyme obtained from fermentation liquid after condensation at alkaline protease activity of （2 000±200） U/mL, neutral protease of （1 500±200） U/mL. The total oil extraction yield reached the highest value of 94.2%, and 90.1% of total protein yield was obtained under conditions that were temperature 55℃, solid/liquid ratio 1：8 g/mL, the initial pH value 10, hydrolysis time 6 h. As compared to the commercial Alcalase protease , the total oil recovery enhanced by 1.9%, the protein recovery reduced by 2% with crude enzyme extraction,and the hydrolyzed protein molecular weights were smaller and distributed wider. The use of crude enzyme resulted in better oil quality as compared with solvent extraction, though no significant difference was observed between the treatments of crude enzyme and Alcalase protease .