Triacylglycerols milkfat

Ruiz-Sala et al. (1996) compared the triacylglycerol composition of the milkfat of sheep, cow and goat by HPLC, using ELSD detection. They... 

Another product manufactured by Loders-Croklaan (Unilever) and named Beta-pol consists mainly of triacylglycerols of the type UPU. This is used as a constituent of infant formulas (191). Human milkfat is unusual in that it contains a significant proportion of its palmitic acid in the sn-2 position. Although this is true also for lard (pig fat), it is not a feature of vegetable oils. Betapol is made from tripalmitin and oleic acid using the lipase from Mucor miehei to promote 1,3-acyl exchange. These materials are expensive, and in practice, fractionated palm oil, rich in tripahnitin, is reacted with acids from high-oleic sunflower or safflower or from olive oil. 

Although in fluid milk the phospholipid fraction is more susceptible to oxidation than the triacylglycerol fraction, in dry milk products, the triacylglycerol fraction is more susceptible to oxidation and the phospholipids act as antioxidants. Thus, solvent-extracted milkfat containing phosphohpids is much more stable to oxidation than milkfat free of phospholipids, obtained by melting churned butter (also called butter oil). The susceptibility of milk phospholipids to oxidation appears to be dependent on whether they are suspended in water or fat. This difference of oxidahve stability influences the development of different flavor defects in various dairy products. With butter, which is a water-in-oil emulsion system containing an aqueous phase of phospholipids dispersed in fat, the phosphohpids oxidize more readily than the triacylglycerol components. 

Figure 1 Three-photon excitation fluorescence micrographs of (a) anhydrous milkfat (AMF) and (b) milkfat triacylglycerols (MF-TAGs) after crystallization at 20°C for 24 h.

Table 2 Fatty Acid Composition of Anhydrous Milkfat (AMF) and Milkfat Triacylglycerols (MF-TAGs) ... 

Figure 7 Solid fat content (%) versus time during static crystallization of (A) anhydrous milkfat (AMF), ( ) milkfat triacylglycerols (MF-TAGs), (O) MF-DAGs-1998 (MF-TAGs with 0.1% DAG added), and ( ) MF-DAGs-2000 (MF-TAGs with 0.1% DAG added) at 25.0°C. Symbols represent the average and standard error of three replicates.

---