Influence of shear flow on polymorphic behavior and microstructural development during palm oil crystallization

Abstract

The influence of shear on the crystallization of palm oil was studied at four different crystallization temperatures (18, 20, 22 and 25 degrees C). Time-resolved X-ray analyses were carried out to study the effect of continuous shear on the crystallization kinetics of the fat. Rheological measurements were used to assess the effect of a shear step on crystallization, and finally polarized light microscopy was used to follow changes in microstructure due to the applied initial shear step. It was shown that shear enhanced the primary crystallization, even when low shear rates were applied for a short period. Furthermore, a shear step prior to crystallization without shear has a marked influence on the microstructural development

Effect of Shearing on Crystallization of Palm Oil-Based Fat Blends

“…As mentioned at the beginning of the paper, there have been a number of recent reports on the crystallization of palm oil under shearing, and this subject has been well elucidated (Mazzanti et al, 2003, Mazzanti et al, 2005, De Graef et al, 2009, Tarabukina et al, 2009. However, the present study supplements these reports by providing further information on the long-term crystallization behavior of palm oil.…”

“…Syringe-extrusion method In the syringe-extrusion method, a 2-mL glass syringe was filled with a mixed fat blend and held at 80℃ before cooling. For rapid cooling, the syringe filled with the fat blend was covered with iced water for 2 min, held at 5℃ for 1 h, and then sheared by extruding 1995, Mazzanti et al, 2003, Mazzanti et al, 2005, Sonwai and Mackley, 2006, De Graef et al, 2009, Tarabukina et al, 2009; however, most of the research was focused on the effect of shearing on initial crystallization behavior. Commercially distributed fat food products are required to maintain their quality over weeks to months.…”

Application of laser backscattering for monitoring of palm oil crystallisation from melt

“…The SWMCL statistic has been found to resemble more closely the Sauter mean diameter measured using laser diffraction instrument and optical microscopy [11,19].…”

“…Miskandar et al [10] examined the effects of cooling time on the crystal distribution of a blend of palm oil and palm olein using a combination of pulsed nuclear magnetic resonance (NMR) and PLM. Rheo-optical techniques have also been applied by De Graef et al [11] and Tarabukina et al [12] to study the effect of shear on crystals development in palm oil. A recent study by Vuillequez et al [13] used optical thermal analysis (OTA) on palm oil to investigate the effect of cooling rate variation on the crystal sizes.…”

Current update on the influence of minor lipid components, shear and presence of interfaces on fat crystallization

“…Therefore, studying the influence of shear on crystallization has a strong practical significance for industrial applications [27 ]. Application of shear usually facilitates nucleation (because of enhanced rate of heat and mass transfer by making boundary layers smaller), promotes faster crystal growth (by affecting the alignment of TAG molecules in the shear field, enhancing inter-particulate collisions and/or increasing the available growth sites due to the breakage of crystals) and also causes faster polymorphic transitions (probably due to melt-mediated transformation of low melting form to higher melting polymorph caused by the increase in local temperature) [3 , 15,28,29,30 ,31,32].…”