Incorporation of Milk Fat and Milk Fat Fractions into Compound Coatings Made from Palm Kernel Oil

¹ University of Wisconsin, Madison 53706

The potential of incorporating anhydrous milk fat and milk fat fractions into compound coatings based on palm kernel oil was investigated. Fractionation of milk fat by melt crystallization was utilized to prepare five fractions with different melting profiles. The anhydrous milk fat and milk fat fractions were added at 5, 10, and 15% of the fat phase in compound coatings made with palm kernel oil. Fats were analyzed for fatty acid and triacylglycerol profiles, solid fat content, thermal profile, and melting point. Coatings that were made with the addition of anhydrous milk fat or milk fat fractions were generally softer than the control coating, although hardness depended on the melting point of the added milk fat fraction. Coatings made with fractionated, hydrogenated palm kernel oil developed fat bloom (the whitish haze that forms on a chocolate surface) faster than coatings made with fractionated palm kernel oil during storage at ambient conditions. As hardness increased, induction time for bloom formation and time to full bloom decreased. Binary mixtures of palm kernel oil and milk fat exhibited diluent mixing effects and contained only ß' polymorph crystals.

Key Words: compound coatings • palm kernel oil • milk fat fractions • fat bloom

Submitted on July 29, 1996
Accepted on March 20, 1997