Chemical Composition of Fat Bloom on Chocolate Products Determined by Combining NMR and HPLC-MS

To reduce unwanted fat bloom in the manufacturing and storage of chocolates, detailed knowledge of the chemical composition and molecular mobility of the oils and fats contained is required. Although the formation of fat bloom on chocolate products has been studied for many decades with regard to its prevention and reduction, questions on the molecular level still remain to be answered. Chocolate products with nut-based fillings are especially prone to undesirable fat bloom. The chemical composition of fat bloom is thought to be dominated by the triacylglycerides of the chocolate matrix, which migrate to the chocolate's surface and recrystallize there. Migration of oils from the fillings into the chocolate as driving force for fat bloom formation is an additional factor in the discussion. In this work, the migration was studied and confirmed by MRI, while the chemical composition of the fat bloom was measured by NMR spectroscopy and HPLC-MS, revealing the most important triacylglycerides in the fat bloom. The combination of HPLC-MS with NMR spectroscopy at 800 MHz allows for detailed chemical structure determination. A rapid routine was developed combining the two modalities, which was then applied to investigate the aging, the impact of chocolate composition, and the influence of hazelnut fillings processing parameters, such as the degree of roasting and grinding of the nuts or the mixing time, on fat bloom formation.

Molecular Origins of Polymorphism in Cocoa Butter

Cocoa butter displays complex crystallization behavior and six crystal polymorphic forms. Although the crystal structure of cocoa butter has been studied extensively, the molecular interactions between cocoa butter triacylglycerols in relation to polymorphic transformations from metastable forms (forms III and IV) to stable crystal forms (forms V and VI) remain largely unknown. In this review, the triclinic polymorphism and melting profiles of the major triacylglycerols in cocoa butter-POP, POS, and SOS-are reviewed, and their binary and ternary phase behaviors in metastable (pseudoβ') and stable (β₂) crystal forms are discussed. We also attempt to clarify how the transformation of cocoa butter from form IV to V, as a critical step in the tempering of chocolate, is controlled by POS interactions with both POP and SOS. Moreover, we show how the crystal forms V and VI of cocoa butter are templated by crystal forms β₃ and β₁ of POS, respectively.

A versatile, flexible synthesis of 1,3-diglycerides and tryglycerides

A flexible method for synthesising 1,30diflycerides and triglycerides is described. Glycidol esters, prepared by a known route from epichlorohydrin and the sodium salt of a fatty acid, were heated with another or with the same fatty acid and a quaternary ammonium salt. This resulted in a fast, mild reaction and higher yields and greater purity of the diglycerides than hitherto obtained in this synthesis. The mixture of 1,3- and 1,2-diglycerides obtained was isomerised by heating while still in the solid phase to 1,3-diglycerides. Triglycerides were prepared from the diglycerides by acylation using a fatty acid chloride and pyridine in hexane.