Comparative analysis of triacylglycerol composition, melting properties and polymorphic behavior of palm oil and fractions

Abstract

Comparative analysis of triacylglycerol composition, melting properties and polymorphic behavior of palm oil and fractionsPalm oil is without doubt the most widely fractionated oil. Dry fractionation is based on differences in the melting points of triacylglycerols (TAG) which will crystallize selectively during the cooling process. Unfortunately, limitations due to intersolubility, closely linked to polymorphism, induce formation of co-crystals at each crystallization step. For this reason, only restricted TAG enrichments are observed. In this work, a series of samples (24) of palm oil, solid and liquid fractions (stearins, mid fractions, oleins and superoleins) have been selected and examined in terms of TAG composition (by HPLC), differential scanning calorimetry (DSC) melting profile and variable temperature powder X-ray diffraction pattern. Three major endotherms [low-melting, highmelting and very high-melting peaks (LMP, HMP and VHMP)] are detected in the DSC melting profiles (5 7C/min). The VHMP is only recorded for palm stearin which contains more SSS components. The HMP contribution is weak for palm olein and even not observed for palm super oleins. The LMP is usually made up of UUU, SUU and SUS components; SUS components are observed in both LMP and HMP; the HMP is also made up of some SSS, except for palm oleins and super oleins. Sub-a 2 , sub-a 1 , a, b' 2 , b' 1 and b polymorphic forms are recorded; the LMP components preferentially crystallize in sub-a 2 , sub-a 1 and a forms; the HMP components generally crystallize in b' 2 and b' 1 , with a tendency to exhibit b crystals, depending on the SSS content. Components of the VHMP have an increased tendency to stabilize in the b form; in view of the results, we can assume that there is a clear relationship between TAG composition, melting properties and polymorphic behavior and of palm oil and fractions.

Structural characteristics of crystals formed in palm oil using sorbitan tristearate and sucrose stearate

“…Three sub-peaks can be observed in the first melting event in the range from 0 to 9°C. Braipson-Danthine and Gibon [41] found that the relative intensity of these sub-peaks is variable, while their positions are related to the TAG composition of the PO, where the first and second sub-peaks are related to the SUU content, and third sub-peak might be related to the SUS content. We can observe a broad peak in the second melting event.…”

Characterization of Coconut Oil Fractions Obtained from Solvent Fractionation Using Acetone

“…5f . Changes in polymorphic structure after fractionation have been observed with other fats such as palm oil 26 and milk fat 6 mainly due to differences in compositions and configurations of the fatty acids and TAGs 23 . The lack of influence of the fractionation conditions on the polymorphism of CNO fractions reported in this work may have lied in the fact that CNO has β -2 as a stable polymorph as already mentioned.…”

Correlation between Thermal Properties and Chemical Composition of Palm Oil Top Olein Fractions

“…Cerretani et al adopted partial least square regression in DSC thermal analysis and quantified the fatty acid composition in olive oil [9]. Other authors found a clear relationship between TAG composition and DSC properties of olive oil and palm oil [10,11]. Haryati et al determined the IV of palm oil by DSC on the basis of bond energy [12].…”