加热氧化对山茶油热力学及流变学特性的影响

Effects of heating oxidation on thermodynamic and rheological properties of Camellia oil

中文关键词:  山茶油  加热氧化  差示扫描量热  流变  精深加工

英文关键词:Camellia oil  Heating oxidation  Differential scanning calorimetry  Rheology  Deep-processing

中文摘要:

      目的 探究加热氧化对山茶油热力学及流变学特性的影响。方法 山茶油经加热氧化处理后，运用差示扫描量热技术（differential scanning calorimetry, DSC）、旋转流变技术，研究其DSC氧化稳定性、熔融结晶特性及黏度随剪切速率、温度变化等特性。结果 山茶油加热时间越长，其DSC热力学氧化稳定性越低，当加热120 min后较初始山茶油的氧化起始温度降低了8.3℃，加热氧化后它的熔融温度及熔融焓降低，主要结晶峰消失。山茶油加热氧化后流动性变差，表现为黏度升高，加热120 min的山茶油较初始山茶油黏度提高了2.8倍，山茶油氧化程度越高，其黏度随温变化的速率越快。结论 加热氧化降低了山茶油的热力学稳定性及流变学稳定性，本研究为山茶油精深加工的热力学性能及流变性能提供了一定的理论支撑。

英文摘要:

      Objective To study the thermodynamic and rheological properties of Camellia oil after heating oxidation. Methods Camellia oil was heated and oxidized at high temperature, then differential scanning calorimetry (DSC) and rotary rheology techniques were applied to study the oxidation stability, melting crystallization characteristics, and viscosity varies with shear rate and temperature of camellia oil. Results The longer the heating time, the lower the DSC thermodynamic oxidation stability of Camellia oil. Compared to the raw camellia oil, the oxidation initiation temperature of Camellia oil which heated for 120 min decreased by 8.3 ℃. The melting temperature and melting enthalpy of Camellia oil decreased through heating, along with the main crystallization peak disappeared. After heating, the fluidity of Camellia oil became worse and the viscosity increased. The viscosity of Camellia oil heated for 120 min was 2.8 times higher than that of the raw Camellia oil. In addition, the higher the degree of oxidation of Camellia oil, the faster the viscosity changed with temperature. Conclusion Deating oxidation decreases the thermodynamic and rheological stability of Camellia oil. This study can provide theoretical support for thermodynamic properties and rheological properties of Camellia oil for deep-processing.