Methylxanthine and catechin content of fresh and fermented cocoa beans, dried cocoa beans, and cocoa liquor

Abstract

The theobromine and catechin content can affect the quality of cocoa liquor and is influenced by cacao variety, production area (PA), and fermentation, as well as the method of drying beans (FDB) and cocoa liquor production (CLP). This study examined variations in methylxanthine and catechin levels in fresh and fermented cocoa beans, dried cocoa grains, and in cocoa liquor from Trinitario, Criollo, and Forastero cacao varieties. A total of 123 cocoa bean samples from three Peruvian PAs at different altitudes, Tingo Maria (TM), San Alejandro (SA), and Curimana (CU), were evaluated. The theobromine (Tb) and caffeine (Cf) contents in fresh cocoa beans were affected by both cocoa type and PA. The caffeine content was higher in Trinitario cacao than in Criollo and Forastero varieties (p ≤ 0.05). The Tb and CF contents decreased in dry cocoa grain and was affected by FDB (p ≤ 0.05) (1.449 ± 0.004 to 1.140 ± 0.010 and 0.410 ± 0.03 to 0.165 ± 0.02 g Tb and C, respectively, per 100 g dry weight). Cocoa beans from Tingo Maria, which has the highest altitude, had higher Tb and CF contents than those from other PAs. The catechin (C) and epicatechin (EC) contents were affected by the FDB and CLP, and were highest in fresh cocoa beans from the Tingo Maria area (range: 0.065 ± 0.01 to 0.020 ± 0.00 g C/100 g). The C and EC contents decreased during FDB and CLP (0.001 g C/100 g of cocoa liquor). Taken together, these results show that higher concentrations of Tb, Cf, C, and EC are present in fresh cocoa beans. Moreover, the cocoa variety influenced cocoa liquor quality. Overall, cocoa from the Tingo Maria PA had the most desirable chemical composition.