Calorimetric approach for the evaluation of chocolate anti-blooming agents’ potentialities following the cocoa butter/milk fat paradigm

The crystallization properties of cocoa butter, milk fat and cocoa butter/milk fat blend 80:20%w/w were explored by means of DSC investigations after rests at different temperature to set up a calorimetric methodology/protocol that leads to a quantitative assessment of the early-stage overall crystallinity in cocoa butter/added fat blends, discriminating the constituent contributions. This quantification is crucial since it is correlated with the early structural state of the matrix in terms of pores and cracks, that is one of the factors that determines the time associated with the blooming onset in chocolate products, and can be used to assess the potentiality of an added fat as a promising anti-blooming agent. Deconvolution and normalization procedures were applied to the DSC curves to obtain the crystallinity evolution for both cocoa butter and milk fat plain systems, which was used to define the degree of crystallinity for the mixed system. The application of the methodology assessed reveals that the main effect of the presence of milk fat, used as a paradigm of a well-known anti-blooming agent in a cocoa based system, is a slowdown of the liquid-solid transition of cocoa butter. Furthermore, in order to directly correlate the calorimetric results with the blooming phenomena, the cocoa butter vs. cocoa butter/milk fat blend comparison was also extended to dark chocolate and simulated milk chocolate matrices, which were investigated through image analysis.