Milk fat lipids

Parodi, P. W. 1975. Detection of aceto-diacylglycerols in milk fat lipids by thin-layer chromatography. J. Chromatogr. Ill, 223-226. 

Precht, D., Molkentin, J., Wolff, R.L. 2001. Comparative studies on individual isomeric 18 1 acids in cow, goat, and ewe milk fats. Lipids, 36, 827-832. 

Robinson, N.P., MacGibbon, A.K.H. 2000. Determination of the conjugated linoleic acid containing triacylglycerols in New Zealand milk fat. Lipids, 35, 789-796. 

Dairy Australia 2004. Dairy Industry in Focus, 2004. Dairy Australia, Melbourne, de Greyt, W., Huyghebaert, A. 1995. Lipase-catalyzed modification of milk fat. Lipid Technol. 7, 10-12. 

E. Flack, Upid Technologies and Applications (ed. F.D. Gunstone and F.B. Padley) Marcel Dekker, New York (1997), pp.305-327. W. de Greyt et al.. Food and non-food applications of milk fat. Lipid Technology, 1993, 5, pp.138-140 Lipase-catalysed modification of milk fat. Lipid Technology, 1995, 7, pp.10-12. 

These assumptions were confirmed by the electrophoresis study of the washed creams. Electrophoresis of purified fat globules is a convenient method to characterize and quantify proteins adsorbed at the oil-water interface [35]. Electrophoretic data indicate that no casein, nor whey proteins, were adsorbed at the surface of raw-milk fat globule. Upon homogenization, caseins adsorbed preferentially at the lipid-water interface. In this case, bound a-lactalbumin accounted for 16% of the total interfacial proteins. Heat treatment also induced the interaction of proteins with the fat globules. The amount of bound proteins (per mg of lipids) for heated raw milk was half that for homogenized milk. 

Milk fat comprises lipids, which are solid at room temperature. If they were liquid, we could correctly call them oils . 

Ice cream serves as a wonderful (and tasty) example of a complex, dynamically heterogeneous food system. A typical ice cream mix contains milk or cream (water, lactose, casein and whey proteins, lipids, vitamins, and minerals), sucrose, stabilizers and emulsifiers, and some type of flavor (e.g., vanilla). After the ingredients are combined, the mix is pasteurized and homogenized. Homogenization creates an oil-in-water emulsion, consisting of millions of tiny droplets of milk fat dispersed in the water phase, each surrounded by a layer of proteins and emulsifiers. The sucrose is dissolved in... 

Figure 13.15 The effect of diet on the Cl 8 1 trans fatty acids in the lipids of human milk (a) diet rich in cows milk fat, (b) diet rich in hydrogenated vegetable oil. (Courtesy of A. Stolyhwo.)...

Fats and other lipids are poorly soluble in water. The larger the accessible surface is—i. e., the better the fat is emulsified—the easier it is for enzymes to hydrolyze it (see p. 270). Due to the special properties of milk, milk fats already reach the gastrointestinal tract in emulsified form. Digestion of them therefore already starts in the oral cavity and stomach, where lipases in the saliva and gastric juice are available. Lipids that are less accessible—e.g., from roast pork—are emulsified in the small intestine by bile salts and bile phospholipids. Only then are they capable of being attacked by pancreatic lipase [4] (see p. 270). 

Because of its wide range of fatty acids, the flavour of milk fat is superior to that of other fats. In certain products and after certain processes, fatty acids serve as precursors of very flavourful compounds such as methyl ketones and lactones. Unfortunately, lipids also serve as precursors of compounds... 

Milk fats, especially ruminant fats, contain a very wide range of fatty acids more than 400 and 184 distinct adds have been detected in bovine and human milk fats, respectively (Christie, 1995). However, the vast majority of these occur at only trace concentrations. The concentrations of the principal fatty acids in milk fats from a range of species are shown in Table 3.6. Notable features of the fatty acid profiles of milk lipids include ... 

The milk fats from marine mammals contain high levels of long-chain, highly unsaturated fatty acids, presumably reflecting the requirement that the lipids of these species remain liquid at the low temperatures of their environments. 

Since about 50% of C16 0 and 100% of C18 0, C18 , and C18.2 are derived from blood lipids, about 50% of the total fatty acids in ruminant milk fat originate from the blood via diet or other organs. 

Lipases are used to hydrolyse milk fat for a variety of uses in the confectionary, sweet, chocolate, sauce and snack food industries and there is interest in using immobilized lipases to modify fat flavours for such applications (Kilara, 1985). Enzymatic interesterification of milk lipids to modify rheological properties is also feasible. 

Dried whole milk is prepared by conventional spray or roller drying, with some modifications of the preheat treatment of the milk. The product is usually stored under nitrogen to delay lipid oxidation and off-flavor development. In spite of the processing changes, flavor defects and short storage life have limited the markets for dried whole milk most of it is used in the confectionery and baking industries. Federal and FAO standards require a minimum of 20% but less than 40% milk fat and a maximum of 5% moisture. 

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