本文研究了纳豆菌液态发酵时间对纳豆菌生物量、蛋白酶酶活、纳豆激酶酶活的影响。在此基础上，研究添加四种谷物（糙薏仁、玉米、荞麦和糙米）对纳豆菌液态发酵产蛋白酶酶活、纳豆激酶酶活、谷物总酚迁移率、总酚残留率以及发酵产物抗氧化活性的影响。结果表明：添加糙米和荞麦可显著促进纳豆菌产蛋白酶（2444.19、1813.71 U/mL）、纳豆激酶（719.67、681.38 U/mL），且以荞麦为底物所产发酵产物的谷物总酚迁移率最高（0.64 mg/g干谷物）、抗氧化活性最强(30.37 μmol trolox equiv/mL)；采用浸泡蒸煮处理四种谷物、延长发酵时间可显著提高其发酵产物的蛋白酶酶活、纳豆激酶酶活、谷物总酚迁移率以及抗氧化活性。采用浸泡蒸煮处理荞麦，利用纳豆菌液态发酵其48 h，可制备富含纳豆激酶、谷物多酚、肽类物质且具有强溶栓、抗氧化活性的功能性食品。

The effects of Bacillus natto liquid fermentation time on biomass and enzyme activities of nattokinase and protease were studied. In addition, the effects of four grains (brown adlay, corn, buckwheat, brown rice) on enzyme activities of protease and nattokinase, migration ratios and residue ratios of grain total phenols, and antioxidant activities of fermentation products by Bacillus natto liquid fermentation were also evaluated. The results showed that buckwheat and brown rice could significantly promote the enzyme activities of protease (2444.19, 1813.71U/mL) and nattokinase (719.67, 681.38 U/mL). The fermentation products obtained by Bacillus natto liquid fermentation with buckwheat possessed the highest of migration ratio of total phenols (0.64 mg/g dry grain) and exhibited the strongest antioxidant activity (30.37 μmol trolox equiv/mL). The enzyme activities of protease and nattokinase, migration ratios and residue ratios of grain phenols and antioxidant activities of fermentation products could be significantly improved by soaking and cooking four grains and extending fermentation time. The functional food rich in nattokinase, grain phenolics, and peptides possessed strong thrombolytic and antioxidant activity could be obtained by Bacillus natto liquid fermentation for 48 h with buckwheat pretreated by soaking and cooking.

广东省自然科学基金项目（2015A030310494）；广州市科技计划项目（20160402172、201710010060）