油脂的相容性和非等温结晶性质对油脂的口感品质有重要影响。为了拓宽椰子油和棕榈油的应用范围,开发以其为主要原料的专用油脂产品,本文通过GC-MS测得椰子油和棕榈硬脂油不同混合比例的总脂肪酸和Sn-2位脂肪酸组成,研究了脂肪酸组成与熔融特性的相关性,再利用脉冲核磁共振仪研究了椰子油和棕榈油的相容性,并用差式扫描量热仪对二者按一定比例混合的复配体系和酶法制备结构脂的非等温结晶行为进行研究。结果表明:不同比例酶法制备结构脂中Sn-2位的月桂酸含量(12.35-46.72%)明显高于物理混合油(5.86-30.75%)。该复配体系整体上存在一定程度的共晶现象,在较高温度(25-45℃)时,相容性较好。在非等温结晶过程中,在同一降温速率条件下,随着椰子油比例的增加,2倍链长的β′型晶体,转变为低熔点的3倍链长β′晶型。
The compatibility and non-isothermal crystallization behavior of oils and fats have important effects on their taste and quality.To explore potential applications of coconut oil and palm stearic oil in the development of new oil-based products,gas chromatography-mass spectrometry(GC-MS) was used to analyze the total fatty acid composition and Sn-2 fatty acid composition of mixtures of coconut oil and palm stearic oil in varying proportions.The correlation between fatty acid composition and melting characteristics was studied,and the compatibility of coconut oil and palm stearic oil was investigated by pulsed nuclear magnetic resonance(NMR).Non-isothermal crystallization behaviors of structured lipids in coconut oil and palm stearic oil mixtures,prepared by physical mixing in different proportions and enzymatic synthesis,were analyzed by differential scanning calorimetry(DSC).The results showed that the content of structured lipid Sn-2 lauric acid was significantly higher in the oils prepared by enzymatic synthesis at different proportions(12.35% to 46.72%) than that prepared by physical mixing(5.86% to 30.75%).There was a certain degree of eutectic phenomenon in this complex system overall and optimum compatibility was found at high temperatures(25 ℃-45 ℃).During non-isothermal crystallization,the β′-crystals with double-chain length structures were converted to the low-melting-point β′-crystals with triple-chain length structures with increasing proportion of coconut oil at the same cooling rate.