腐乳发酵过程中酶活力和化学组分变化研究

通过发酵罐培养高大毛霉MHC-7，并对腐乳发酵过程中酶活力及化学组分变化规律进行研究。结果表明：MHC-7 在发酵罐扩大培养条件下，最佳发酵时间是30h。蛋白酶、α- 淀粉酶、α- 半乳糖苷酶、谷氨酰胺酶、纤维素酶、脂肪酶、糖化酶和果胶酶活力在豆坯上产酶的峰值时间分别是48、36、48、48、66、36、30 和72h；在腐乳后发酵中除谷氨酰胺酶呈上升趋势，其它几种酶都呈下降趋势，粗蛋白、粗脂肪和还原糖含量随着发酵时间的延长不断下降，氨基态氮、游离脂肪酸和总酸含量不断增加；当达到谷氨酰胺酶≥ 86.3U/g、总酸≥ 1.0%、氨基态氮≥ 0.45%、还原糖≤ 1.1% 及黏度≤ 2 × 105mPa·s 时可以作为为判断腐乳成熟的标准。

Study on Change of Enzyme Activity and Chemical Composition of Sufu during Fermentation

In this study, Mucor mucedo MHC-7 was cultured in fermentor for producing sufu. During the fermentation, the change of enzyme activity and chemical composition of sufu were investigated. The results showed that: the best fermentation time of MHC-7 in fermentor is 30 h; the activity peak time of protease, α-amylase, α-galactosidase, glutaminase, cellulase, lipase, glucoamylase and pectolase in soybean billet is 48, 36, 48, 48, 66, 36,30 and 72 h; except α-galactosidase activity increasing, the activities of the other enzymes decrease; and the contents of crude protein, crude fat and reducing sugar decline with fermentation time extending, but the contents of amino nitrogen, free fatty acids and total acid increase unceasingly. In conclusion, α-galactosidase activity ≥ 86.3 U/g, total acid content ≥ 1.0%, amino nitrogen content ≥ 0.45%, sugar content ≤ 1.1% and viscosity ≤ 2 × 105 mPa·s can be taken as the signs of maturity of sufu.