A phenolic fraction was obtained from of the acetone-water-acetic acid extract of Inga edulis leaves, by liquid-liquid partition and SPE-C18 cartridges. This method provided an increase of 108, 66, 51, 50 and 36% of flavonols, proanthocyanidins, total polyphenols, gallotannins and flavanols, respectively. The major phenolics in purified fraction were procyanidin B2, catechin and myricetin-3-O-α-L-rhamnopyranoside, which achieved increases of 111, 47 and 45%, respectively, after SPE. Acid hydrolysis confirmed the presence of procyanidins, prodelphinidins and glycosylated flavonoids.

High-quality dark chocolates (70% cocoa content) can have shades from light to dark brown color. This work aimed at revealing compounds that discriminate black and brown chocolates. From 37 fine chocolate samples from years 2019 and 2020 provided by Valrhona,8 dark black samples and 8 light brown samples were selected. A non-targeted metabolomics study was performed based on ultra-high performance liquid chromatography—high resolution mass spectrometry/mass spectrometry experiments, univariate, multivariate, and feature-based molecular networking analyses. Twenty-seven overaccumulated discriminating compounds were found for black chocolates. Among them, glycosylated flavanols including monomers and glycosylated A-type procyanidin dimers and trimers were highly representative. Fifty overaccumulated discriminating compounds were found for brown chocolates. Most of them were B-type procyanidins (from trimers to nonamers). These phenolic compounds may be partially related to the chocolate colors as precursors of colored compounds. This study increases the knowledge on the chemical diversity of dark chocolates by providing new information about the phenolic profiles of black and brown chocolates.

Dehydrodicatechins resulting from (epi)catechin oxidation have been investigated in different foods and natural products, but they still offer some analytical challenges. The purpose of this research is to develop a method using ultra-high performance liquid chromatography coupled with trapped ion mobility spectrometry and tandem mass spectrometry (UHPLC−ESI−TIMS−QTOF−MS/MS) to improve the characterization of dehydrodicatechins from model solutions (oxidation dimers of (+)-catechin and/or (−)-epicatechin). Approximately 30 dehydrodicatechins were detected in the model solutions, including dehydrodicatechins B with β and ε-interflavanic configurations and dehydrodicatechins A with γ-configuration. A total of 11 dehydrodicatechins B, based on (−)-epicatechin, (+)-catechin, or both, were tentatively identified in a grape seed extract. All of them were of β-configuration, except for one compound that was of ε-configuration. TIMS allowed the mobility separation of chromatographically coeluted isomers including dehydrodicatechins and procyanidins with similar MS/MS fragmentation patterns that would hardly be distinguished by LC-MS/MS alone, which demonstrates the superiority of TIMS added to LC-MS/MS for these kinds of compounds. To the best of our knowledge, this is the first time that ion mobility spectrometry (IMS) was applied to the analysis of dehydrodicatechins. This method can be adapted for other natural products.

Introduction: This study aimed to evaluate the color and the discriminating compounds for two types of cocoa beans (black and brown beans) related to 70% dark chocolates of black and brown colors from a previous work of our group.Methods: Color analysis and untargeted high-resolution mass spectrometry-based metabolomic analysis were performed on eight beans of each type. Mass spectral data processing, univariate and multivariate statistical methods were conducted for classification of beans and selection of discriminant features.Results and discussion: The results showed that the color difference already observed for black and brown chocolates preexists in the beans. Black and brown beans had 45 and 50 discriminant features, respectively, of which 16 and 41 were phenolic compounds. Most of them were also previously identified as discriminating compounds for black and brown chocolates. Black beans predominantly contained glycosylated flavanols, ranging from monomers to trimers, with dimers and trimers being A-type procyanidins, along with a phenolic acid (protocatechuic acid), and an O-glycosylated flavonol (quercetin-3-O-glucoside). In contrast, brown beans mostly contained non-glycosylated B-type procyanidins ranging from dimers to decamers, but also dimers and trimers of A-type procyanidins, and a glycosylated and sulfated flavanol ((epi) catechin hexoside-sulfate). These markers may be useful for quality control purposes and may contribute to the selection of beans that yield black or brown dark chocolates.