不同WPNI脱脂乳粉对发酵乳饮料稳定性的影响

Study on the stabilization system of fermented milk drinks induced by skimmed milk power of different WPNI

以TSI(动力学稳定性指数)、粒径、ΔBS(背散射光强变化值)为指标,比较6种以不同WPNI的脱脂乳粉为原料的发酵乳饮料体系的稳定性,并利用SDS-PAGE分析了发酵乳饮料的离心沉淀物质成分。结果表明:发酵乳饮料的原料脱脂乳粉WPNI值越低,即未变性蛋白含量越低,脱脂乳粉热变性程度越大,产品的TSI值越高,粒径越大,ΔBS也越大,饮料体系的稳定性越差。通过SDS-PAGE分析得到,沉淀物质主要为casein,β-lg,α-La,还有少量的Lf和BSA。

This research, using TSI （dynamic stability index）, particle size and A BS （back scattered light intensity change） as indexes,compared the stability of the fermented milk beverage system produced from six different types of skim milk powder with different WPNI values,and analysised the content the ingredients of centrifugal precipitation in fermented milk beverage with SDS-PAGE.The results showed that lower WPNI value （lower the undenatured protein content）indicates higher the thermal denaturation degree of skim milk power,higher TSI value, larger particle size and larger A BS. Besides, stability of the beverage system with lower WPNI value was lower as well. The SDS-PAGE anal- ysis also revealed that the precipitated substances were mainly casein,β-lg, α-La, and a small amount ofLf, BSA.