Thermal analysis of palm stearine by DSC

Abstract

Abstract The chemical composition and thermal properties of palm stearine have been investigated. The sample consists of triglycerides containing mainly the fatty acid residues: palmitic (P) 51.4%; oleic (O) 32.7%; linoleic (L) 8.3% and stearic (S) 5.0%. The sample melts as almost two independent components in separate temperature ranges. DSC analysis and analogy with the work of Persmark et al. (1) indicate that the high melting component, consisting mainly of the triglycerides POP (33%), PPP (≈15%), POS (4%) and PPS (2%), crystallizes initially in an α crystal form which rearranges on tempering successively to β′ and β crystal forms. The constitution of the lower melting component is much more dependent on thermal history but is mainly POO (14% overall), PLP (13% overall) and SOO (1% overall). It crystallizes initially in a sub α form which rearranges to β′ when tempered at 0°C and to the β crystal form when tempered at 10°C. The liquid phase contains mainly PLO (8% overall), OOO (6% overall), PLL (4% overall) and LOO (1% overall).