Blooming in Cocoa Butter Substitutes Based Compound Chocolate: Investigations on Composition, Morphology and Melting Behavior

To provide a comprehensive analysis on the development of bloom on cocoa butter substitutes based compound chocolate, the morphology, chemical composition and melting behavior were examined. Atomic force microscopy (AFM), scanning electric microscopy (SEM), and polarized light microscopy (PLM) measurements were carried out to study the morphological properties of chocolate. AFM analyses showed a crystal growth which was confirmed by using PLM. SEM revealed that the crystal network of fresh chocolate disappeared in the chocolate matrix but constituted a denser one in the bloom which indicating a phase separation. This was confirmed qualitatively by using high performance liquid chromatography and differential scanning calorimetry, where different contents of triacylglycerols and melting behavior were observed in the bloom and the chocolate matrix. Moreover, polymorphism translation from beta' form to beta form appeared in the bloom but did not in the chocolate matrix, which suggesting that polymorphism translation is the result rather than the cause of bloom formation.