Distinction of Ecuadorian varieties of fermented cocoa beans using Raman spectroscopy

Abstract

Cocoa (Theobroma cacao) is a crop of economic importance. In Ecuador, there are two predominant cocoa varieties: National and CCN-51. The National variety is the most demanded, since its cocoa beans are used to produce the finest chocolates. Raman measurements of fermented, dried and unpeeled cocoa beans were performed using a handheld spectrometer. Samples of the National and CCN-51 varieties were collected from different provinces and studied in this work. For each sample, 25 cocoa beans were considered and each bean was measured at 4 different spots. The most important Raman features of the spectra were assigned and discussed. The spectroscopic data were processed using chemometrics, resulting in a distinction of varieties with 91.8% of total accuracy. Differences in the average Raman spectra of cocoa beans from different sites but within the same variety can be attributed to environmental factors affecting the cocoa beans during the fermentation and drying processes.

Keywords: CCN-51; Chemometrics; National variety; Raman spectroscopy; Theobroma cacao.