Molecular Changes during Germination of Cocoa Beans, Part 1.

Area of Science:

• Agricultural Science
• Food Chemistry
• Metabolomics

Background:

• Cocoa bean germination is a known phenomenon during fermentation.
• The specific impact of this germination on cocoa fermentation's molecular profile and flavor remains largely unknown.

Purpose of the Study:

• To investigate the molecular and flavor implications of cocoa bean germination during fermentation.
• To identify key metabolites affected by germination using an untargeted metabolomics approach.

Main Methods:

• Untargeted metabolomics using Ultra Performance Liquid Chromatography-Electrospray Ionization-Time of Flight-Mass Spectrometry (UPLC-ESI-ToF-MS) with MS^e.
• Analysis of raw versus germinated cocoa bean extracts using principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA).

Main Results:

• Germination significantly altered metabolite profiles, with down-regulation of 12-hydroxyjasmonic acid (HOJA) sulfate, (+)-catechin, and (-)-epicatechin.
• Up-regulation of two hydroxymethylglutaryl (HMG) glucosides (A and B) and other HMG glucosides was observed in germinated beans.
• 12-hydroxyjasmonic acid (HOJA) and its sulfate were identified for the first time in cocoa and linked to bitter and astringent taste profiles.

Conclusions:

• Cocoa bean germination during fermentation leads to significant molecular changes affecting flavor precursors.
• Identification of specific metabolites like HOJA and HMG glucosides provides insights into the biochemical pathways influenced by germination.