全脂奶粉的脂肪氧化动力学研究

目的]研究全脂奶粉在不同贮存温度下的脂肪氧化行为。方法]选用硫代巴比妥酸值(TBA值)为评价指标,考察了温度和时间对全脂奶粉脂肪氧化的影响,并分别对脂肪氧化程度和脂肪氧化速率进行了动力学分析。结果]当保存温度在30～40℃时,脂肪氧化随时间的变化符合一级反应动力学;当温度为50℃时,脂肪氧化随时间的变化同时符合一级和零级反应动力学,但是零级反应动力学更准确。全脂奶粉脂肪氧化一级反应动力学的活化能Ea为29.81 kJ/mol。结论]利用脂肪氧化速率随温度变化的动力学模型,可以预测30～50℃任意温度下的全脂奶粉脂肪氧化速率常数。

Study on Kinetics of Lipid Oxidation of Whole Milk Powder

Objective ] To study lipid oxidation of whole milk powder under different storage temperature. Method ] The effects of time and temperature on lipid oxidation of whole milk powder were studied with TBA value as evaluation index, and the kinetic analysis of both the ex- tent and the rate of lipid oxidation were respectively investigated. Result ] The results showed that the relationship between lipid oxidation and time can be described by a first order model when storage temperature is from 30℃ to 40℃, and can be described by both a first order model and a more accurate zero order model when storage temperature is from 50℃. The activation energy of lipid oxidation of whole milk powder fit to a first order model is 29.81 kJ/mol. Conclusion] The rate constant of lipid oxidation with storage temperature from 30 ℃ to 50℃ can be calculated by using the kinetic model between lipid oxidation and temperature.