基于培养基优化和保护剂筛选的直投式酸奶发酵剂的研制

Study on the direct-to-vat culture based on culture medium optimization and protective agent screening

利用正交试验确定了嗜热链球菌和保加利亚乳杆菌培养基优化,冷冻保护剂筛选实验的最佳条件。添加1.0%番茄汁+0.3%玉米浆+2.0%乳糖的优化培养基具备良好生理特性,谷氨酸钠与脱脂乳对菌种活性在冷冻过程中有明显保护作用。在优化工艺下,冻干后活菌数分别达到4.3×10^(11)cfu·g^(-1)和4.2×10^(11)cfu·g^(-1);冻干粉复配成直投式发酵剂后具有良好的发酵特性,完全符合发酵高粘度酸奶用直投式发酵剂的要求。

In this paper, the optimization experiment condition of culture medium optimizing and cryoprotecrants screening was determined for Streptococcus.thermophilus and Laetobacillus bulgaricus by orthogonal experiment. and the best of the. Optimized medium has good physical properties with adding mixture of 1.0% tomato juice, 0.3% corn pulp and 2.0% lactose.Sodium glutamate and skimmed milk have obvious protective effects on bacterial activity in the freezing process. In the optimization process, their viable count can separately reach 4.3×1011cfu·g^-1 and 4.2×1011cfu·g^-1 in the freeze-dried microbial powder. The Direct-to-vat cultures, consistted of both freezedried microbial powder, had good characteristics in compliance with the high viscosity yogurt fermentation.