温度和微射流处理对乳清分离蛋白颗粒性质的影响

Effects of Temperature and Microfluidization Treatments on the Particle Properties of Whey Protein Isolate(WPI)

本文旨在研究微射流处理对不同温度下乳清分离蛋白(WPI)颗粒性质的影响。以微射流处理与温度为变量,对WPI的SDS-PAGE电泳、示差扫描量热特性、平均粒径、ζ电位、表面疏水性(Ho)与乳化活性指数(EAI)进行了表征与测定。结果表明:在所有的温度下,经微射流处理的WPI的平均粒径及Ho均小于未经微射流处理的WPI,但ζ电位高于未经微射流处理的WPI。无论是否经过微射流处理,在60℃以下时,WPI的Ho基本上不受温度影响,在60℃以上时,其Ho随温度的升高而增大,在80℃下达到最大,如微射流处理前后WPI在80℃下的Ho分别为3786和3082。此外,在60℃以下时,WPI的EAI基本上不受温度影响,在60℃以上时,其EAI随温度的升高而增大,在80℃下达到最大,如微射流处理前后WPI在80℃下的EAI分别为130.5 m2/g和120 m2/g。微射流处理前后WPI平均粒径及EAI的变化可能与WPI颗粒间ζ电位和Ho的共同作用有关。

The aim of this paper was to study the effect of microfluidization treatment on the particle properties of whey protein isolate （WPI） at different temperatures. With the microfluidization treatment and temperature as variables, the WPI was analyzed here by sodium dodecyl sulfate polyacrylamide gel electrophoresis （SDS-PAGE） and differential scanning calorimetry, and the average particle size, zeta-potential, surface hydrophobicity （Ho） and emulsifying activity index （EAI） of the WPI were characterized and measured. The results showed that both the average particle size and Ho of the WPI treated with microfluidization were smaller than those of the WPI without microfluidization treatment at all temperatures, whereas the zeta-potential of the WPI treated with microfluidizafion was higher than that of the control WPI. Regardless of whether the WPI was treated with microfluidization, Ho of the WPI was basically tmaffected by the temperature when it was below 60℃, increased with the increasing temperature when it was above 60 ℃, and reached a maximum at 80 ℃. For example, the H0 values of WPI treated without or with microfluidization at 80℃ were 3786 and 3082, respectively. Besides, the EAI of the WPI was basically unaffected by the temperatures when the temperatm＇e was below 60℃, increased with increasing temperature when the temperature was above 60 ℃, and reached a maximum at 80 ℃. For example, EAI values of the WPI treated without or with microfluidization at 80℃ were 130.5 and 120 m^2/g, respectively. The changes in the average particle size and EAI without and with microfluidization treatment may be associated with the synergistic effect of the zeta-potential and Ho of the WPI.