Roasting is the most important technological operation in cocoa beans processing, and the degree of chemical changes depends on the temperature applied during the process. Roasting is the operation for the development of aroma and flavour of cocoa beans at temperatures of 110°C to 140°C and time range of 20 to 50 min.
Roasting involves complex chemical transformations, attributed to Maillard reactions, caramelization of sugars, protein degradation, and synthesis of sulfur compounds.During roasting, some compounds increase in concentration, the volatile fraction decreases, and new compounds are formed. Moisture loss and chemical reactions suffered by the beans in the roasting process affect the color, volume, mass, shape, bead pop, pH, density, and especially volatile compounds and flavor.
The selection of process parameters has a decisive influence on the nature of chemical and physical changes occurring in the cocoa beans, which determines the quality of the final products.
The color is one of the most important physicochemical properties of roasted cocoa beans because it affects the quality of products derived from this commodity. Brown color is preferred to red-violet. This parameter depends not only on contents of polyphenols and anthocyans and their derivatives but also on the presence of Maillard reactions products and products of starch dextrinization.
Pyrazines, a by-product of Maillard reaction is one of the character impact compounds that contribute to unique cocoa flavour.
The precursors of flavour are developed during fermentation and drying of cocoa beans, which include the free amino acid, peptides and reducing sugar, contributing to the development of cocoa specific aroma through Maillard reaction during roasting.
Cocoa bean roasting process
