微波加热过程中油脂升温特性的研究

利用微波工作站实时测定微波加热时油脂升温情况以及不同冻藏时间的油脂经微波复热时的温度变化情况,考察了微波复热过程中油脂的种类和冻藏条件对油脂温度变化的影响。结果表明,大豆油、葵花籽油、花生油等6种植物油微波升温特性有差别:葵花籽油因不饱和脂肪酸含量较高,升温较快;花生油的不饱和脂肪酸含量较低,升温较慢。置于-20℃冻藏1d后,6种油脂微波复热曲线均会呈现S型,而且凝固点高的花生油复热最慢,到达0℃所需时间最长。将大豆油分别置于-20℃和-30℃连续冻藏一个月,冻藏温度越低对油脂微波复热温度变化影响越小,复热曲线越稳定;在同一冻藏温度下,冻藏时间越长对油脂复热影响越小。 

Study on the temperature-raising characteristics of oil during microwave heating

The change of temperature in oil and frozen oil during microwave reheating was determined by microwave workstation. The effects of different freezing conditions on temperature changing of oil and frozen oil during microwave reheating were investigated. Results showed that there were differences between heating characteristics of 6 kinds of oil, heating rate of the sunflower oil was higher since it contained more unsaturated fatty acid, but the peanut oil was on the contrary. Frozen for 1 day under-20℃, reheating curves of the 6 kinds of oil were all presented the “S ” pattern, but the heating rate of peanut oil was lowest, because its freezing point was the highest, which means it need more time to reach 0℃. The soybean oil was stored at-20℃ and-30℃ respectively for a month, and reheated regularly, finally found the lower frozen temperature the smaller impact on the temperature change of oil after microwave heating, when under the same freezing temperature, impact decreased with freezing time increased.