Influence of Fatty Acid Moieties of Sorbitan Esters on Polymorphic Occurrence of the Palm Mid‐Fraction

Abstract

The influence of chain length and subcell packing of fatty-acid moieties in sorbitan esters (SE) on the polymorphism of the palm midfraction (PMF) was examined. SE with different fatty-acid moieties (sorbitan tripalmitate; sorbitan tristearate [STS]; and sorbitan tribehenate [STB]) were blended with PMF and PMF polymorph formation was examined using synchrotron radiation X-ray diffraction and differential interference contrast microscopy. PMF without additives was crystallized in the β 0 form under the isothermal condition at 22 C; however, the addition of STS, which forms an α subcell structure, promoted the crystallization of PMF in the α form. In contrast, crystallization of PMF in the β 0 form was accelerated by the addition of STB. These results showed that when the chain length of the fatty-acid moiety between fat and emulsifiers was similar, the crystallization of PMF in the α form was promoted by the α subcell packing in STS crystals that were nucleated prior to PMF crystallization. In contrast, STB crystals, which have an α subcell packing, accelerated the crystallization of PMF in the β 0 form because of the large difference between the chain lengths of STB and PMF. Therefore, structural similarities in both the chain length and the subcell packing are essential features that regulate the template effect, and the promotion of the crystallization of PMF in the β 0 form by the addition of STB was caused by heterogeneous nucleation.Keywords Template effect Á Heterogeneous nucleation Á Fat crystallization Á Emulsifier Á Subcell packing Á Chain length structure J Am Oil Chem Soc (2018) 95: 709-720.

Coconut Oil Crystallization on Tripalmitin and Tristearin Seed Crystals with Different Polymorphs

“…The TAG molecules are adsorbed into the step for nucleation. Palm oil and sorbitan esters clearly show template effect nucleation when the sorbitan ester has the same fatty acid moiety as that of palm oil . However, the β′ was the most effective polymorph in both PPP (4.16 nm) and StStSt (4.62 nm) for the crystallization of CO in our study, even at longer lamella distances than that of the CO-β′ crystal (3.39 nm) (Table ).…”

“…Palm oil and sorbitan esters clearly show template effect nucleation when the sorbitan ester has the same fatty acid moiety as that of palm oil. 20 However, the β′ was the most effective polymorph in both PPP (4.16 nm) and StStSt (4.62 nm) for the crystallization of CO in our study, even at longer lamella distances than that of the CO-β′ crystal (3.39 nm) (Table 1). This indicates that polymorphic matching between seeds and target TAG crystals is more significant if TAG is used as the seed crystal.…”

The Role of Emulsifiers on the Crystallization of Cocoa Butter and Cocoa Butter-sugar Blends

“…9,58 Generally, liquid-state emulsifiers do not enhance primary stage nucleation while solid-state emulsifiers may enhance early-stage nucleation via a templating effect, where the emulsifier will nucleate first and act as surfaces for ensuing TAG crystallization. 59,60 The ability of lecithin to enhance secondary growth was also observed, though this may have been a by-product of a greater number of high-melting nuclei present after primary growth resulting in a greater surface area for secondary growth to occur, however, non-phospholipid compounds in lecithin may have also caused this enhancement.…”