纳豆激酶豆乳液体发酵条件优化

Optimization of Liquid Fermentation Conditions for Soybean Milk with Nattokinase

心脑血管疾病已经严重威胁人类健康,其发病率和死亡率均居各种疾病之首。纳豆激酶作为一种理想的预防和治疗血栓的天然功能食品被广泛关注,因此研究纳豆激酶的规模化生产对于推进溶栓类功能食品的开发具有重要意义。在前期发酵豆乳工艺优化的基础上,对因素顺序及因素水平稍作调整,以全豆豆乳为发酵基质,以纳豆激酶为功能评价指标,发酵后出渣率及终点pH为参考指标,通过单因素及正交试验确定最佳发酵工艺。结果表明,发酵豆乳的最佳工艺条件为:发酵时间30 h,装液量5%,初始pH5.5,接菌量1.5%。在此发酵条件下,酶活可高达660 184.14 IU/mL,是优化前(79 434.68 IU/mL)的8.31倍,是前期最佳工艺下纳豆激酶表达量(429 869.34 IU/mL)的1.54倍。与前期全豆豆乳最佳工艺条件相比,通过调整初始pH和接菌量的先后顺序,可以在更低接菌量(前期研究,最佳接菌量为1.75%)的基础上,显著增加纳豆激酶表达量。通过本实验研究既节约了成本也提升了纳豆激酶的表达量,对纳豆激酶的规模化生产具有重要意义。

Cardio-cerebrovascular diseases have seriously threatened human health,and morbidity and mortality from them are the highest among all kinds of diseases.Nattokinase is widely concerned as an ideal naturally functional food for prevention and treatment of thrombosis,thus the research on the scale production of nattokinase is of great significance to promote the development of thrombolytic functional food.Based on the previous optimization study of fermented soybean milk technology and slightly adjusting the factor sequence and factor level,the fermentation conditions were optimized by single factor and orthogonal experiments,while using whole soybean milk as fermentation medium,nattokinase as function evaluation index,and the slag rate and finial pH as auxiliary indexes.Result showed that the optimal fermentation conditions were determined as follows:the fermentation time was 30 h,the liquid volume in flask was 5%,the initial pH was 5.5,and the amount of bacteria was 1.5%.The nattokinase activity was 660 184.14 IU/mL under this condition,which was 8.31 times of that before optimization(79 434.68 IU/mL)and 1.54 times of previous optimized study(429 869.34 IU/mL).The enzyme production significantly increased by adjusting initial pH and the order of inoculation even with lower amount of inoculation,compared to the optimized process of whole bean milk with inoculation 1.75%.This study confirmed that the cost can be eliminated while the nattokinase production can be improved,which is significant for the large-scale production of nattokinase.