Modification of Milk Fat

Milk fat may be chemically modified to obtain products with altered functionality. In contrast to physical modification of milk fat where the position and nature of the fatty acid chains of the triacylglycerols are maintained, the use of chemical processes results in modification of the composition of the fatty acid chains or their positions in the triacylglycerol molecule. 

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This chapter is focussed on the post-farm modification of milk fat by physical, chemical or enzymic means. The use and control of these processes for differentiation of milk fat to widen its application range or tailor it for specific end-applications (Mortensen, 1983 Mogensen, 1985 Boudreau and Arul, 1991 Rajah and Burgess, 1991) will be discussed. The effects of the modification processes and minor lipid components on the texture and crystallization behavior of milk fat are covered. The potential for applying modification processes to improve the nutritional quality of milk fat is also considered. 

Physical modification of milk fat by fractionating milk fat or by blending milk fat or milk fat fractions with other oils and fats results in products with an altered triacylglycerol composition, but one in which the fatty acids in milk fat maintain their original position in the triacylglycerol molecules (Kaylegian, 1999). 

Modification of Milk Fat Properties by Addition of Minor Lipids... 

Minor lipids can have a significant influence on the kinetics of crystallization of milk fat. The effects on the kinetics of crystallization processes should be separated from their influence on the final properties of the milk fat. The effects of minor lipids on the modification of milk fat properties are complex and are dependent on the type, chemical nature, concentration and structure of the minor lipids (Wright and Marangoni, 2002a Vanhoutte et al., 2002a). 

Boudreau, A., Arul, J. 1991. Physical and chemical modification of milk fat. 2.1 Fractionation. In, Monograph on Utilizations of Milk fat, Bulletin, No. 260, International Dairy Federation, Brussels, pp. 7-15. 

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. 

Balcao, V.M., Malcata, F.X. 1998. Lipase catalysed modification of milk fat. Biotechnol. Adva. 16, 309-341. 

Enzymatic modification of milk fats with lipolytic enzymes has already been mentioned above. Besides this it is possible to manufacture complex cheese flavours today also by fermentation of raw materials of cheese processing with defined microorganisms. Roquefort and other blue cheese flavours fermented by the mould Penicil-lium Roqueforti are currently in commercial production. 

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. 

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