Melting characteristics of milk fat butter and margarine with varied linoleic acid
Murphy, M.F.; Dunkley, W.L.; Wood, F.W.
Journal of Dairy Science 57(5): 585
1974
ISSN/ISBN: 0022-0302
Accession: 026949703
Milk fats and butters containing elevated linoleic acid were prepared from milk produced by cows fed a protected lipid supplement. For comparison, butter and margarines were purchased from commercial sources. Melting characteristics were determined at selected temperatures by dilatometry and nuclear magnetic resonance. Dilatometry sho wed that percentages of crystalline fat and of linoleic acid were inversely related. At 15 C, fat from polyunsaturated margarine, normal milk fat, and milk fat containing 20% linoleic acid had solid fat concentrations of 22, 58, and 16%. Corresponding rates of melting were 1.0, 4.1, and 1.,6% per degree. Milk fat containing 20% linoleic acid resembled polyunsaturated margarine in percent solid fat at 15 C, but its higher rate of melting indicated a narrower plastic range. For the butters and margarines, changes in the resonance signal with increasing temperature were inversely related to, the melting rates, of the separate fats as determined by dilatometry.