Thermal properties of fats and oils

Abstract

1. Melting points and x-ray diffraction patterns have been determined for cottonseed oil hydrogenated to an iodine value of less than 1, and for a very pure sample of tristearin. 2. Contrary to the observations of previous investigators, the x-ray patterns indicate a well-defined crystal structure with a sharp long spacing and a single sharp short spacing in the lowest-melting form of tristearin. A new pattern, with two short spacings and a long spacing, was observed in tristearin of intermediate melting point. 3. Four polymorphic forms of the hydrogenated cottonseed oil were detected. The x-ray pattern of the lowest-melting form of the hydrogenated oil was similar to that of the correspopnding form of tristearin. The pattern of the highest-melting form of the hydrogenated oil differed from that of either tristearin or β-palmitodistearin, the major components of the oil. Distinctive patterns for the intermediate forms of the hydrogenated oil could not be obtained, presumably because of the instability of the lower melting forms at room temperature.