益生菌干酪乳杆菌Zhang和双歧杆菌V9发酵豆乳的研究

对益生菌Lactobacillus casei Zhang和Bifidobacterium animalis V9单独及混合(1:1)发酵豆乳及以其制作的活性豆乳饮料进行研究,并测定了豆乳37℃发酵期间及活性豆乳饮料4℃28d贮藏期间的pH、TA、FAN和活菌数。结果表明,豆乳发酵过程中,混合发酵豆乳酸度变化大于单独发酵且可有效缩短发酵时间;B.animalis V9发酵的豆乳FAN含量变化最大。活性豆乳饮料贮藏期间,含有B.animalis V9活性豆乳饮料的pH值和TA变化不明显,含有L.casei Zhang活性豆乳饮料的pH值显著降低,TA显著升高;所有样品的FAN在贮藏7d期间显著下降,之后变化不明显;在28d贮藏结束时,L.casei Zhang和B.animalis V9单独及混合发酵豆乳饮料时活菌数分别是2.28×109cfu/g、4.27×108cfu/g、1.56×109cfu/g和2.8×108cfu/g。本研究初步表明,在豆乳中L.casei Zhang和B.animalis V9混合发酵优于单独发酵,在活性豆乳饮料中L.casei Zhang和B.animalis V9具有优良的贮藏稳定性,显示了其应用于发酵豆乳制品具有良好的潜力。

Investigation of the Growth and Survival Activities of Probiotics Lactobacillus casei Zhang and Bifidobacterium animalis V9 in Soymilk

The growths of probiotics Lactobacillus casei Zhang and Bifidobacterium animalis V9 in soymilk fermented individually and combinely at a ratio of 1：1, and their survival activities in formulated soymilk drink prepared by fermented soymilk were investigated. The pH value, titration acidity（TA）, free amino nitrogen （FAN） and the probiotics viable counts of soymilk fermented at 37 ℃ were determined every 3 h for 24 h, and the mentioned four index of soymilk drink were also determined each week during 4 ℃ storage for 28 days. The results indicated that the acidity rate Of soymilk fermented combinely by L.casei Zhang and B.animalis V9 was faster than individually, which could effectively shorten the fermentation time. During storage, the biggest FAN content and the smallest pH and TA changes were observed in soymilk fermented with B.animalis V9 individually, while the pH values decreased and TA increased significantly in soymilk drink fermented with L.casei Zhang, respectively. The FAN decreased significantly after 7-day storage in all samples, but afterwards the FAN had no obvious change. After 28-day storage at 4 ℃, the viable counts in soymilk drink fermented L.casei Zhang and B.animalis V9 individually and combinely were 1.74×10^9cfu/g, 1.02×10^9 cfu/g, 1.07×10^9 cfu/g and 1.05×10^9 cfu/g, respectively. Therefore, it is proved preliminarily that the properties of soymilk drink fermented with L.casei Zhang and B.animalis V9 combinable were better than individually.