Contrastive analysis of lipid composition, thermal and crystallization behavior of olein/stearin fractionated by novel layer melt crystallization from palm oil.

Background Melt crystallization is typically recognized as a high-efficient and green method for oil fractionation. This work concentrated on the novel layer melt crystallization for preparing desirable olein and stearin products from palm oil and the evaluation of fractions quality. Layer melt crystallization was performed at varied temperature parameters and their effects on fractions were evaluated by iodine value (IV), solid fat content (SFC) and melting point. The lipid composition, thermal and crystallization properties, and phase behaviors of the final optimized fractions were determined using Gas Chromatography (GC), high-performance liquid chromatography-atmospheric pressure chemical ionization mass spectrometry (HPLC/APCI-MS) and Differential Scanning Calorimeter (DSC). Results Increasing crystallization tube temperatures under the same jacket temperature increased the melting point and SFC, while decreased the IV of the olein product. Opposite results were observed in stearin products. Major fatty acids in fractions were determined as palmitic acid and oleic acid. 1,2-Dioleoyl-3-palmitoyl-glycerol (POO) and 1,3-dipalmitoyl-2-oleoylglycerol (POP) were identified as the main triacylglycerols in olein and stearin fractions, respectively. Critical effect of crystallization temperature on co-crystallization of oleins and stearins was revealed. A transition from plate-like crystal growth to spherulitic growth with spontaneous nucleation was indicated in palm oil and stearin fractions with increasing crystallization temperature. As for olein fractions, the temperature increase resulted in heterogeneous nucleation from instantaneous nucleation. Conclusion In this study, novel layer melt crystallization was successfully applied and optimized for fractionating the palm oil. The composition and property changes of obtained fractions were analyzed and explained from both macro and micro levels. This article is protected by copyright. All rights reserved.