Effects of convective and microwave roasting on the physicochemical properties of cocoa beans and cocoa butter extracted from this material

Cocoa beans are the basic raw material for the production of chocolate and other chocolate products. To obtain these products, the seeds must be subjected to a complicated technological process in which one of the key steps is roasting. A widely used method of roasting cocoa beans is convection roasting which is based on subjecting the raw beans to a flow of hot air in the temperature range between 130-150°C for 15 – 45 min. (Belitz and Grosch, 1999, Minifie 1989, Nebesny and Rutkowski, 1998, fiwiechowski 1996). The influence of high temperatures on the beans contributes to many physical and chemical changes that significantly alter their properties. Roasting produces the characteristic aroma of cocoa, the loss of water, volatile acids and tannin compounds, as well as the deepening of the brown color of the bean and the assurance of its microbiological purity (Belitz and Grosch, 1999, Benz, 2002, Jinap et al., 1998, Lee SY. et al., 2001; Minifie 1989, Nebesny and Rutkowski, 1998, Redgwell et al., 2003; fiwiechowski 1996, Trojanowska and Trojan 1999). The literature reviews suggest that these features were studied taking into account the general impact of process parameters such as temperature and time. (Brito et al., 2000, 2002, Jinap et al., 1998, Nebesny and Rutkowski, 1998), and only a few works (Krysiak et al., 2003, Krysiak and Motyl-Patelska, 2005) analyzed how other, important process parameters, namely relative humidity and air flow velocity, shaped these changes. The use of increased air humidity in the roasting process has a beneficial effect on bean properties (eg, improves the degree of sterilization of the material (Benz, 2002), color (Krysiak, 2006), or the fat content of cocoa (Krysiak and Motyl-Patelska, 2005). However, in the literature, there is a lack of information on how the increased humidity of air will affect the properties of the main ingredient of cocoa beans namely cocoa butter. Convection roasting of cocoa beans has a number of drawbacks. One of them is that due to the traditional way of heat and energy transfer, the heat treatment process takes too long. This may RESUMEN