Triacylglycerol composition and thermodynamic profiles of fractions from dry fractionation of anhydrous milk fat

Abstract

This research provided a more in-depth look at the physiochemical properties of milk fat. The milk fat was fractionated between 30 and 15 °C into eight fractions with different melting points, the cooling step were successively 30, 25, 20 and 15 ℃. Physiochemical properties of different fractions, which include fatty acids, triacylglycerols, thermodynamics, and crystallization behavior, also were analyzed by using GC, UPLC-ESI MS, DSC and XRD. The results showed that the melting point of 30 S could reach 38.2 ℃ compared with the native milk fat (31 ℃) after fractionation. As the fractionation temperature decreased, the content of long-chain saturated fatty acids decreased. However, the content of short and medium-chain saturated fatty acids and unsaturated fatty acids showed an increasing trend, and the corresponding saturated triacylglycerols were also reduced. Besides, the high melting point fractions were mixed dominantly by β' crystal form at room temperature. The crystallization or melting temperature was relatively high, and the latent heat of phase change also was large. Therefore, these results demonstrated that the milk fat quality could be improved by dry fractionation and its application was expanded in production.