Effects on Phase Transitions in Tripalmitin due to the Presence of Dipalmitin, Sorbitan‐Monopalmitate or Sorbitan‐Tripalmitate

Abstract

The effects of diglycerides, sorbitan-monoesters and sorbitantriesters on triglyceride polymorphic transitions have been examined.Earlier reported effects of retardation of + p transitions due to the presence of asymmetric diglycerides were found to be the same from the racemic and antipode forms. The a * p and p' + p transitions of tripalmitin (PPP) were followed when sorbitan-monopalmitate (SMP), sorbitan-tripalmitate (STP), or dipalmitate (DP) were present. The STP gave a slightly stronger reduction in transition kinetics than DP, whereas SMP was found to promote the transition. In order to understand the mechanisms involved the binary systems SMP-PPP and STP-PPP were examined. In the case of SMP-PPP a 1 : 1 molecular compound is formed, whereas STP-PPP shows a simple eutectic behaviour. I n t r o d u c t i o n A major problem in many fat-based food products is polymorphic transition of fat crystals during storage. Margarine and chocolate are well-known examples where transitions to the most stable crystal form lead to unacceptable product quality. The present work was undertaken in order to compare the effect of different lipids known to influence the kinetics of the polymorphic transitions, and furthermore in order to understand their function.Sorbitan esters have been utilized in various applications to inhibit the 6' + /? phase transition (cf. Ref.').The possibility to use diglycerides in order to prepare margarine from low-erucic acid rapeseed oil was studied in our laboratory'. In order to obtain comparative data on these two routes of crystallization modification, we report below a systematic study on effects of different isomers of distearin (DS) on trimyristin (MMM) polymorphism and of sorbitan-tripalmitate (STP), sorbitanmonopalmitate (SMP) and 1,2-D-dipalmitate (DP) on tripalmitin (PPP) polymorphism. Binary systems of these components were examined, and in one set of experiments we used the same fatty acid chain length in order to obtain optimal conditions for co-crystallization. E x p e r i m e n t a l Samples of trimyristin, tripalmitin, DM and DP were obtained from Sigma (> 99% in purity). STP and SMP were kindly provided by Dr. N . Krog, Grindsted Products, Brabrand, Denmark. They were purified from corresponding technical products with a purity of about Samples were mixed and equilibrated about 30°C above the melting point of the high-melting component. They were then chock-cooled to -20°C and then kept at the constant temperature where phase transition kinetics were studied (20°C, 30°C and 40"C, respectively). Melting and solidification points of binary systems were obtained from observations in the polarizing microscope 95 Y o . Phasenumwandlungen io lkipalmitin in Gegenwart von Dipalmitin, Sorbitan-Monopalmitst oder Sorbitan-lkipalmitat Die Wirkungen von Digiyceriden, Sorbitan-Monoestern und Sorbitan-Triestern auf die Kristallisation der Triglyceride wurden untersucht. Die Verzogerung von 0' + Ubergangen in asymmetrischen Diglyceriden war gleichartig in racemischen und antipodischen Formen. ...

Influence of emulsifiers on the crystallization of solid lipid nanoparticles

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A Microfluidic Approach for a Continuous Crystallization of Drug Carrier Nanoparticles

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Physical properties of fats in food

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