A rheometer-based method to determine the crystal types of cocoa butter in white chocolate

Understanding of cocoa butter crystallization mechanism throughout chocolate production is an important part to achieve the desired quality of chocolate. The alterations in the polymorphic composition of cocoa butter have a significant effect on the crystal stability and the tendency of the crystal to transition into other forms. In this study, rheological analysis by temperature scanning test used to evaluate characteristic gelling and melting properties, was applied to white chocolate samples which were melted at different temperatures (37 °C, 50 °C) and solidified at different storage conditions (25 °C, 4 °C, − 18 °C) as well as to solid white chocolate samples (control) which have not been melted at all. The goal was to determine the chocolate melting temperature by identifying the starting point (onset) of the descent of the prob gap as a result of the deterioration of solid phase of chocolate samples in the rheometer. The crystals contained in the solid white chocolate were not determined using any rheological method so far. However, in this study, the crystal types composing the main body of the three white chocolate samples were determined by rheometer. Consequently, the effect of melting and resolidifying of white chocolate on the possible cocoa butter crystal types throughout the storing process has been observed. Further evaluation has been made on the fatty acid profile of chocolate to detect whether the variations in crystal types is originating from fatty acid composition or not. It was found that palmitic acid, stearic acid and oleic acid are the dominating acids in white chocolate and there is no statistically significant difference between fatty acid compositions ( p > 0.05).