Assessment of cocoa powder changes during the alkalization process using untargeted metabolomics

This work is focused on the study of the metabolomic changes that occur in cocoa powder throughout the alkalization process by using an untargeted ultra high-performance liquid chromatography coupled to high-resolution mass spectrometry (UHPLC-QTOF-MS) metabolomics approach. With this aim, cocoa powder samples submitted to different alkalization degrees (light, medium, and strong) were analyzed. Metabolite extraction was performed using 75% MeOH in water since it provided the highest number of molecular features. After data processing, non-supervised and supervised methods were applied to carry out the statistical data analysis. Thus, the most significant metabolites that allow establishing differences among the cocoa powder samples submitted to the alkalization processes were pointed out. Thus, 43 and 30 metabolites in positive and negative ionization modes, respectively, demonstrated to be relevant. Among them, 9 compounds were unequivocally identified and 22 tentatively identified. Most of them were amino acids, alkaloids, organic acids or polyphenols, among others.