Effects of hydrophobic emulsifier additives on crystallization behavior of palm mid fraction in oil‐in‐water emulsion

Abstract

Ultrasonic velocity measurements and X-ray diffraction were employed to monitor the crystallization behavior of palm mid fraction (PMF) in oil-in-water emulsions (20 vol%). Three hydrophobic emulsifiers-sucrose oligoesters (SOE) containing palmitic acid (P-170) and stearic acid (S-170) moieties and a polyglycerine ester (DAS-750) containing a stearic acid moiety-were added to PMF in an attempt to increase the rate and extent of crystallization of PMF, which are otherwise suppressed owing to emulsification of the oil phase into many droplets. The results revealed that the hydrophobic emulsifiers accelerate the nucleation of PMF in the emulsion system, while retarding the rate of crystal growth. As a result, the crystallization temperature (T c ) of PMF increased with increasing concentrations of the hydrophobic emulsifiers. The effects of the three additives were different; in particular the addition of DAS-750 remarkably enhanced crystallization at low concentrations. By adding the emulsifiers at higher concentrations, the polymorphic behavior of PMF crystallization was also modified to different degrees, depending on the type of emulsifier. With addition of SOE, PMF crystallized predominantly in the β′ form; with addition of DAS-750, the extent of β′ nucleation was reduced by comparison with that observed with SOE. The results were explained in terms of adsorption of the hydrophobic emulsifier additives at the oil-water interface, which provides a template for acceleration of surface heterogeneous nucleation of PMF in the emulsion system.Paper no. J9846 in JAOCS 78, 837-842 (August 2001).

Effect of Cooling and Heating Rates on Polymorphic Transformations and Gelation of Tripalmitin Solid Lipid Nanoparticle (SLN) Suspensions

“…29 To make stable SLN suspensions for the encapsulation and protection of sensitive bioactive ingredients, it is necessary to either retard the polymorphic transition or to control the aggregation stability. 24 There have been many studies on modification of the crystallization and polymorphic behavior and stability of lipids in emulsions as well as SLN by varying surfactants, 19,20,[30][31][32][33][34][35] lipid composition, 36 particle size and distribution, 30,37,38 aqueous phase composition, and application of shear. [39][40][41] Because the gelation of SLN was observed shortly after crystallization of the lipid nanoparticles, [22][23][24] it is important to investigate the gelation phenomenon under different crystallization conditions.…”

Effects of Addition of a Palmitic Sucrose Ester on Low-Trans-Fat Blends Crystallization in Bulk and in Oil-in-Water Emulsions

“…These emulsifiers would then have the ability to perform the same roles as catalytic impurities. However, this effect was not found in several fats such as palm mid fraction or palm kernel oil [9][10][11] . The effect of P-170 proved to be more specific than an impurity effect.…”

“…It was reported that addition of sucrose esters accelerated crystallization in emulsions formulated with palm kernel oil or palm mid fraction [9][10][11] . However, this behavior was not found in those fats crystallized in bulk.…”

“…In addition to their major function of producing and stabilizing emulsions, SE have numerous other functional roles as texturizers, film formers, and modifiers of crystallization. Several reports have dealt with the effect of SE on the crystallization behavior of fats, both in bulk and in emulsion systems; however, some of these results may be considered contradictory [4][5][6][7][8][9][10][11][12][13][14] . For a selected fat in bulk, none of these authors has reported both effects: acceleration or delay with supercooling.…”

Physical properties of shortenings with low‐trans fatty acids as affected by emulsifiers and storage conditions

“…Previous research has demonstrated that the addition of emulsifiers can modify the crystallization be-havior of lipids by either delaying or promoting the crystallization either in bulk lipids or in emulsions. Sato's group studied the effect of diacyglycerols on the crystallization of oilin-water emulsions [12,13]. Herrera's group studied the effect of sucrose ester with different HLB values on the crystallization behavior of bulk lipids [14][15][16][17][18].…”