Seed color as an indicator of flavanol content in Theobroma cacao L

Seed color has long been associated with quality traits of the cacao tree, Theobroma cacao L., namely disease resistance and the flavor of chocolate produced from its seeds. Flavanol compounds are central to many of these quality traits and this study investigates the relationship between seed color and flavanol content in the seed. Colorimetric data was collected for 200 T. cacao seeds, each individually analyzed for relative flavanol concentrations by HPLC MS. A significant positive relationship (p<0.0000) was found between total flavanols and pigmented anthocyanin compounds. Colorimetric seed color data showed that "lightness" of the outer seed surface, as measured by L*-values, is only modestly predictive of flavanol content. Individual seed extracts consistently revealed the presence of four pigmented anthocyanin compounds; in order of decreasing abundance, they were a cyanidin arabinoside, cyanidin galactoside, cyanidin rutinoside, and cyanidin pentoside. The last two, whose identifications were confirmed by tandem MS, were previously unidentified in cacao. During this investigation, a method was developed for the efficient quantification of procyanidins. These compounds, of interest in many foods, were analyzed from fresh cacao seed extracts. Comparative procyanidin profiles for each seed were obtained using a polyethylene glycol column to separate oligomers. Data on retention times and mass chromatographs led to the identification of procyanidin monomers through pentamers with putative identifications of hexamers through decamers based on retention time and similar spectral traces. Benefits of this system as a rapid method for procyanidin characterization are discussed.