COCOA PROCESS MARKERS: THE EFFECT OF TEMPERATURE ON POLYPHENOL AND BIOGENIC AMINE PROFILES

A variety of factors determining cocoa quality are strongly related to the cocoa beans processing, from the opening of the fruit until the end of industrial processes. In particular, qualitative characteristics of the cocoa beans are a consequence of the differences in the farming practices regarding growing, fermenting and drying, with significant differences sometimes found in samples from the same country. In this work processing steps of cocoa beans from Perù (Coviriali) was extensively studied in the polyphenol and biogenic amines (BAs) profiles, investigating the influence of roasting temperatures on the concentration of both classes of active compounds. Cocoa beans and dark chocolates contain substantial amounts of the monomeric flavan-3-ols, catechin and epicatechin as well as oligomeric and polymeric procyanidins. These natural components are associated with the cardiovascular health benefits of cocoa powder and dark chocolate. The HPLC/DAD analysis led to the identification of xanthines (theobromine and caffeine), procyanidins (catechin, epicatechin and other procyanidins), hydroxycynnamic derivatives and flavonols (quercetin derivatives). Roasting is known as a crucial step in technical treatment of cocoa, which leads to flavanol losses and modifications, especially the epimerization of epicatechin to catechin. The ratio epicatechin/catechin as a food quality marker was also evaluated. The potential toxicity of BAs and the possibility of using them as food quality markers is related with the hygienic-sanitary quality of the process and with the freshness of the raw materials and the processed products. This makes analytical determination of this class of compounds quite important under the food quality and safety point of view. This work clearly showed as the exposure to different roasting temperatures strictly influenced the BAs total amount and an increased concentration was recorded with temperature. Moreover, the data displayed that BAs level never represented a possible risk for consumer health, according to the toxicity levels reported in literature and regarded as acceptable. Finally, the correlation between some polyphenols concentration and BAs formation during roasting was also evident as consequence of antioxidant species to avoid amino acid degradation.