发酵核桃乳优良益生菌的筛选及蛋白酶活力的测定

Screening of excellent strains of probiotics of the second generation for fermenting walnut milk and determination of the protease activity

以分离自健康人体、酸泡菜、保健品等的13株第2代新型益生菌为试验菌株,研究了13株菌在纯核桃乳中的生长活力、产酸特性及感官性能,筛选出了适宜发酵核桃乳的益生菌,并分析了筛选出的菌株发酵核桃乳的蛋白酶活力。结果表明:13株第2代新型益生菌中干酪乳杆菌05-20和植物乳杆菌07-191在纯核桃乳中37℃发酵12 h后,活菌数分别为7.83×10~8、8.20×10~8 cfu/m L,p H值分别为5.05、5.06,产酸能力强、繁殖活力高、感官风味和组织状态俱佳;其他11株菌的活菌数均低于6.40×10~8 cfu/m L;2株菌在纯核桃乳中37℃培养12 h后蛋白酶活力分别为0.838、1.064 U/m L。研究结果为进一步研发益生菌发酵核桃乳产品奠定了基础,也为其他植物蛋白的精深加工提供了思路和方法。

The experimented strains, 13 new-type probiotics of the second generation, in this study were isolated from healthy human beings, pickles, health care products and so on. The growth activity, characteristics of producing acidity and sensory properties were studied in this research, screening out probiotics suitable to fermenting walnut milk. And the protease activities of fermenting walnut milk were analyzed. The experimenting results of the pure walnut milk fermented by lactobacillus casei 05- 20 and lactobacillus plant arum 07-191 for 12 h in 37 ~C are as follows： viable counts reached 6.92x108 cfu/mL,7.76x108 cfu/mL, respectively, pH values were 5.05, 5.06, respectively, they have strong acid- producing and high reproduction activity with excellent sensory flavor and texture, the viable counts of the other 11 probiotics were all below 6.40×108 cfu/mL, the protease activities of the pure walnut fermented by lactobacillus casei 05-20 and lactobacillus plant arum 07-191 were 0.838 U/mL, 1.064 U/mL, respectively. This study laid the foundation for furtherly studying the fermenting walnut milk products and also provided ideas and methods for the deep processing of other plant proteins.