Dairy Chemistry And Biochemistry

MILK LIPIDS 139

1001

80

20

0

10 20 30 40 50

Temperature ("C)

Figure 3.39 Melting point curves of unfractionated milk fat (a), fraction solid at 25°C (b),

fraction liquid at 25°C (c) (from Mulder and Walstra, 1974).

emulsion of the oil with dairy cream for the manufacture of butter or by

blending the oil directly with butter.

In addition to modifying the rheological properties of butter, blends of

milk fat and vegetable oils can be produced at a reduced cost (depending

on the price paid for milk fat) and have an increased content of polyunsatu-

rated fatty acids, which probably has a nutritional advantage. Oils rich in

0-3 fatty acids, which are considered to have desirable nutritional proper-

ties, may be included in the blend, although these oils may be susceptible to

oxidative rancidity.

Low-fat spreads. Spreads containing 40% fat (milk fat or blends of milk
fat and vegetable oils), c. 3-5% protein and selected emulsifiers are now
commonly available in many countries. These products have good spreada-
bility and reduced caloric density (see Keogh, 1995).

High meltingpointproducts. Butter may be too soft for use as a shortening
in certain applications; a more suitable product may be produced by
blending butter and lard or tallow.