共固定甘氨酸甜菜碱与植物乳杆菌在高盐稀态酱油酿造中的应用

摘要

报道了甘氨酸甜菜碱对高渗条件下植物乳杆菌(Lactobacillus plantarum YSQ18)形态的影响,并研究了甜菜碱与乳杆菌共固定化技术对提高高盐稀态酿造酱油蛋白质转化率、缩短酱油发酵周期等的作用.利用包埋法将甜菜碱与乳杆菌制成共固定化颗粒,加入酱醪自然发酵.电镜观察显示,外源添加甜菜碱时,处在高盐环境的植物乳杆菌YSQ18生长良好,细胞形态与正常培养相近.发酵结果表明,共固定化组氨基酸态氮、全氮相比空白组分别增加0.234 g/100 mL和0.358 g/100 mL.氨基酸态氮生成率和蛋白质转化率比空白组分别提高1.7％和6.7％,比单独固定乳杆菌和添加游离乳杆菌与甜菜碱的实验组平均提前约1周时间达到发酵终点,与空白组相比提前幅度更为明显.因此,该共固定化技术在酱油酿造中具有较好的应用价值.%The effects of glycine betaine (GB) (one of compatible solutes) on the morphology of Lactobacillus plantarum under high osmotic pressure were studied.Co-immobilized GB with lactic acid bacterium,Lactobacillus plantarum,were used in a pilot scale high salt liquid-state soy sauce fermentation process to improve the conversion rate of the protein and shorten the fermentation period.The embedding method of sodium alginate was conducted for the co-immobilizing of GB and lactic acid bacterium into particles which was added to the fermented soy sauce mash,and measured the total acid and amino acid during the fermentation process.It was showed by electron microscopy that Lactobacillus plantarum with GB grew well under high salt condition,and the cell morphology was similar to the one with normal culture.The soy sauce pilot showed that,compared to the normal control group,the amino acid nitrogen of the co-immobilized group increased 0.234 g/100mL,the total nitrogen content increased 0.358 g/100mL,and the amino acid conversion and protein utilization increased by 1.7％ and 6.7％ compared to the normal control group.The fermentation period for co-immobilized group was shorten by 1 week compared to single fixed lactobacillus group and the test group with addition of free lactobacillus and betaine,and this phenomena was more obvious compared to blank group.It's concluded that co-immobilized GB with lactic acid bacteria has positive effect on soy sauce brewing process.