Identification of Methylxanthines and Phenolic Compounds by UPLC-DAD-ESI-MS OTOF and Antioxidant Capacities of Beans and Dark Chocolate Bars from Three Trinitario×Forastero Cocoa (Theobroma cacao L.) Hybrids

摘要

Interest on Trinitario cocoa has continuously increased due to the fact that some genotypes of this group had inherited some characters of vigorosity from Forastero and the flavor grade of Criollo. The pronounced incompatibility between Trinitario clones orientates research on the crossing of Trinitario clones with other varieties of cocoa in order to increase productivity and cocoa beans quality. Polyphenols and methylxanthines are bioactive compounds responsible for the health benefits of cocoa and cocoa based products. Cocoa is a crop with a high content of bioactive compounds in the plant kingdom. This study aims at correlating genotypes, methylxanthines and polyphenols as well as antioxidant activity of beans and dark chocolate derived from Trinitario×Forastero hybrids. Total polyphenol content and total condensed tannin contents were determined by spectrophotometric methods. Individual bioactive compounds were identified by UPLC-DAD-ESI(+)-MS both in beans and dark chocolate bar. Results showed differences within beans of dark chocolate and between beans and dark chocolate. Beans from the hybrid (♀)SNK10×(♂)IMC67 recorded the highest polyphenol content (49.18±1.55mg CatE/g) considering the two matrices. The highest concentration of condensed tannins (22.81±0.69 mgCatE/g) was recorded in beans obtained from the hybrid (♀)ICS40×(♂)UPA134. Dark chocolate bar from beans of the hybrid (♀)ICS40×(♂)UPA134 was the richest in condensed tannins (18.25±0.71 mg CatE/g). The total polyphenol and total condensed tannin contents, the chemical composition as well as the antioxidant activity could be genotype-dependent and were affected negatively during roasting. In fact, roasting decreased the polyphenol content and consequently the antioxidant activity. (-)-epicatechin, theobromine, ferulic and chlorogenic acids and their derivatives, procyanidin C1, caffeine and salicylic acid 3-O-glucose/galactose were identified in beans and/or dark chocolate.