Classification of cacao beans (Theobroma cacao L.) of southern Mexico based on chemometric analysis with multivariate approach

Abstract

The aim of this study was to group samples of cacao collected in Southern of Mexico. For this, several physical bean variables (weight, length, width and bean circumference), chemical (moisture, ash, fat, protein, fatty acids) in addition to polyphenol content and antioxidant capacity (ABTS method) were measured. Forty-five cacao samples derived from plants with Criollo phenotype, and a control sample of T. bicolor was included. All variables were analyzed by multivariate analysis (principal component analysis—PCA, k-means and discriminant analysis—DA). The four physical bean traits were not useful when incorporated into the analysis altogether with the chemical variables and led to wrong grouping, and the PCA did not separate T. bicolor of the cocoa samples, so they were discarded for further analysis. Among chemical variables, those that contributed most to the variance and explained the total variance (PCA) were palmitoleic, palmitic, oleic and stearic fatty acids, as well as moisture content and polyphenol content. All samples were classified into seven homogeneous groups. The geographical origin of the samples did not correlate with chemometric grouping, which shows little influence of microclimates, the possible dispersion of highly related materials or individuals adapted to the microenvironmental conditions of the region. Multivariate analysis allowed the grouping of individuals of cacao based on six chemical characteristics of the beans.