Impact of Cooling Profile on Refined Palm Oil Crystallization: Microscopic and Small and Wide‐Angle X‐Ray Scattering Investigations
Abstract
Among the different possible strategies, thermal control is a major lever to control the fat structure (i.e., triacylglycerols molecules organization and crystals morphology). In this article, we determined the impact of thermal treatments on TAGs packing tendency contained in refined palm oil (RPO). The thermal behavior of RPO was studied using X-Ray Scattering technics, polarized light microscopy analysis and differential scanning calorimetry. Three cooling profiles were considered: slow, intermediate and fast. Fast cooling leads to the formation of small spherulitic crystals while slow cooling induces the formation of large discoid crystalline aggregates. Both structures were identified when RPO is crystallized following an intermediate cooling profile. Slow cooling induces the formation of β’ polymorphic form in sequence as 2Lβ’ then 3Lβ’ configurations. RPO rapidly cooled first crystallizes in α form before to turn into 2Lβ’ structure. At intermediate cooling profile, 2Lβ’ and 3Lβ’ are observed but at lower temperatures compared to slow cooling, and another original phase ϕ is formed around 0 °C. This phase has similarities with the sub-α phase observed in cocoa butter which corresponds to a β’ subcell and presents the capacity of adapting its composition during cooling, leading to an increase of its interplanar distances by decreasing temperature. This article is protected by copyright. All rights reserved