嗜酸乳杆菌和双歧杆菌发酵乳的流变特性研究

以两株嗜酸乳杆菌(KLDS AD1、KLDS AD2)和3株双歧杆菌(长双歧杆菌KLDS 2.0001、婴儿双歧杆菌KLDS 2.0002和KLDS 2.0604)分别发酵的酸乳为研究对象，测定其pH值、滴定酸度、质构及流变学特性。pH值和滴定酸度测定结果表明嗜酸乳杆菌产酸能力强于双歧杆菌。质构测定结果表明嗜酸乳杆菌发酵的酸奶质地较为结实。5种酸乳的剪切力升速和降速曲线都能形成触变环，触变环的面积大小为KLDS 2.0604＞KLDS 2.0001＞KLDS AD2＞KLDS 2.0002＞KLDS AD1，即婴儿双歧杆菌KLDS 2.0604在剪切力破坏下其组织状态的恢复力最差，很难恢复到起始状态。表观黏度曲线在下降时只有婴儿双歧杆菌KLDS 2.0002没有出现突增现象，其弹性最差。综合得出嗜酸乳杆菌KLDS AD2发酵乳的组织状态、黏弹性最好。

Rheologic Properties of Lactobacillus acidophilus and Bifidobacterium Fermented Milk

In this paper,5 yogurts fermented by 2 Lactobacillus acidophilus and 3 Bifidobacterium were used as the experimental subjects to explore their pH,titratable acidity,dynamic rheology and texture profile.The results indicated that the acidproducing capacity of Lactobacillus acidophilus fermented milk was stronger than that of Bifidobacterium fermented milk.Texture profile analysis showed that texture of Lactobacillus acidophilus fermented milk was hard.All samples showed a strong thixotropic loop behavior in the rising and decline curve of shearing force,and the size of thixotropic loop was decreased according to the order of B.infantis KLDS 2.0604,B.longum KLDS 2.0001,Lb.acidophilus KLDS AD2,B.infantis KLDS 2.0002 and Lb.acidophilus KLDS AD1,which suggested that the recoverability of B.infantis 2.0604 fermented milk was the weakest under the condition with the damage of shearing force.A sudden increase in the pattern of apparent viscosity was not observed in KLDS 2.0002 fermented milk,which revealed the poor elasticity of KLDS 2.0002 fermented milk.All of these investigations showed that the texture and viscoelasticity of KLDS AD2 fermented milk should be the best.