产胞外多糖副干酪乳杆菌HCT对酸乳品质的影响

Effect of an exopolysaccharide-producing strain of Lactobacillus paracasei HCT on the quality of yoghurt

在嗜热链球菌单菌发酵剂或保加利亚乳杆菌和嗜热链球菌混合发酵剂2种常规发酵剂的基础上添加产胞外多糖(EPS)副干酪乳杆菌HCT共同发酵,研究HCT对酸乳理化、质构以及流变学特性的影响。结果表明:与不加HCT的对照相比,在混合发酵剂中添加质量分数为1%的HCT菌株,凝乳时间可缩短0.5h,酸乳成品的硬度和黏着性分别提高了0.23N和3.81N;而在单菌发酵剂中添加则产酸较慢,延长发酵时间,酸乳成品的硬度和黏着性分别降低0.12N和1.0N,但内聚性增加了0.15。此外,在2种发酵剂中添加HCT均能显著提高酸乳成品的黏度,具有一定的抗剪切破坏作用,同时赋予酸乳良好的色泽、口感和组织状态,对持水力的影响也不显著。

The milk was added strain HCT which produce EPS to two conventional yogurt starters consisting ofLactobacillus Streptococcus thermophilus and Lactobacillus bulgaricus ,and the non-HCT milk was used as control. The physicochemical, rheological and texture properties of yogurt were measured. The results displayed that compared with non-HCT contrast,adding 1% HCT strain to the mixed starter,the time of coagulation was reduced half an hour and the hardness,adhesiveness were promoted 0. 23 N and 3. 81 N; however, adding single starter exhibited lowed acid producing and prolonged fermentation time,also the hardness,adhesiveness were decreased 0.12 N and 1.0 N,but the cohesion was increased by 0.15. The results showed that adding HCT strain could significantly increase the viscosity of yogurt products,and enhance shear stress resistance, and also improve the color, taste and organizational status of yogurt; however, the effect on water holding capacity was not notable.