Chemical and thermal characteristics of milk fat fractions isolated by a melt crystallization.

Anhydrous milk fat (AMF) was fractionated by a
two-stage dry fractionation process to produce three fractions:
high melting (HMF), middle melting (MMF), and low melting
(LMF). The HMF (m.p. 42~ exhibited a broad melting range
similar to a plastic fat. The MMF (m.p. 33~ resembled the original
AMF (m.p. 31~ but with slightly higher solid fat content.
The LMF (m.p. 16~ was liquid at ambient temperature. Differences
in the thermal properties of these fractions were attributed
to the triacylglycerols (TAG) and their fatty acid composition.
Saturated TAG with carbon numbers of 36-54 were concentrated
in the HMF; whereas unsaturated TAG of carbon
number 36-54 predominated in the LMF. Likewise, the longchain
saturated fatty acids were significantly higher and the
long-chain unsaturated fatty acids were significantly lower in
the HMF fraction. Binary blends of milk-fat fractions with a
range of melting profiles were produced by mixing HMF with
AMF, MMF, or LMF. Laboratory-prepared fractions were similar
to commercially available fractions.