喷雾干燥生产酸奶粉工艺研究

Study on the Technology of Producing Yogurt Powder by Spray Drying

本研究对单菌发酵剂的制备、发酵参数以及喷雾参数进行优化,获得酸奶粉的最佳生产工艺.菌种比例(保加利亚乳杆菌:嗜酸乳杆菌:嗜热链球菌)为2∶2∶3,接种量为牛奶体积的5%(保加利亚乳杆菌:6.85×10~6cfu/mL,嗜酸乳杆菌:7.71×10~6cfu/mL,嗜热链球菌:1.35×10~7cfu/mL),发酵时间为8h,是酸奶发酵的最佳条件.此时酸奶中的的菌数为6.0×10~8cfu/mL;喷雾干燥机进口温度为150℃,进料流量为300mL/h,β-环糊精含量为0.015g/mL,是酸奶粉喷雾干燥的最佳条件.酸奶粉中的活菌率为78.4%,成品呈乳白略带淡黄色.

In this study,the preparation,the fermentation parameters and the spray parameters of the single bacteria fermentation agent were optimized,and the best production process of the yogurt pow-der was obtained.The best condition of yogurt fermentation is as following：the proportion of bacteria （Lactobacillus bulgaricus,Lactobacillus acidophilus,Streptococcus thermophilus） is 2∶2∶3,the in-oculation of milk volume is 5% （Lactobacillus bulgaricus：6.85×10^6cfu/mL,Lactobacillus acidophi-lus：7.71×10^6cfu/mL,Streptococcus thermophilus：1.35×10^7cfu/mL）,and the fermentation time is 8 h.Under the above condition,the number of bacteria in yogurt is 6×108cfu/mL,the inlet tem-perature of spray dryer is 150℃,the feed flow rate is 300mL/h,and the content of beta cyclodextrin is 0.015g/mL,which forms the best condition for spray drying of yogurt powder.The rate of living bacteria in yogurt powder is 78.4% with the product in milky whitel ight yellow.