Chemometric Classification of Cocoa Bean Shells Based on Their Polyphenolic Profile Determined by RP-HPLC-PDA Analysis and Spectrophotometric Assays.

Olga Rojo-Poveda,Caroline Stévigny,Ilario Ferrocino,Giuseppe Zeppa,Letricia Barbosa-Pereira

doi:10.3390/antiox10101533

Abstract

The cocoa bean shell (CBS), a byproduct from the cocoa industry, was recently proposed as a functional and low-cost ingredient, mainly because of its content in polyphenols. However, vegetal food products could significantly differ in their chemical composition depending on different factors such as their geographical provenience. This work is aimed to determine the polyphenolic and methylxanthine profile of different CBS samples and utilize it for achieving their differentiation according to their geographical origin and variety. RP-HPLC-PDA was used to determine the CBS polyphenolic profile. Spectrophotometric assays were used to obtain the total phenolic, flavonoid, and tannin contents, as well as to evaluate their radical scavenging activity. The results obtained from both methods were then compared and used for the CBS differentiation according to their origin and varieties through chemometric analysis. RP-HPLC-PDA allowed to determine 25 polyphenolic compounds, as well as the methylxanthines theobromine and caffeine. Polyphenolic profile results highlighted significant differences among the analyzed samples, allowing for their differentiation based on their geographical provenience. Similar results were achieved with the results of the spectrophotometric assays, considered as screening methods. Differentiation based on CBS variety was instead obtained based on the HPLC-determined methylxanthine profile.

Highlights

The cocoa bean shell (CBS) is one of the main byproducts of the chocolate manufacturing industry, usually discarded after cocoa bean husking
On the second step of this work, principal component analyses (PCA) were applied to the obtained results for a chemometric differentiation of the CBS samples according to their geographical origin or variety based on their polyphenol and methylxanthine contents
This study provides information about the polyphenolic profile of CBS, obtained by both RP-HPLC-PDA Analysis and Spectrophotometric Assays for a large set of samples

Summary

Introduction

The cocoa bean shell (CBS) is one of the main byproducts of the chocolate manufacturing industry, usually discarded after cocoa bean husking. In contrast to other cocoa byproducts such as the pod and the mucilage, CBS is usually discarded in a later step of the cocoa manufacture process, and it was reported that more than 700,000 tons of CBS waste are produced worldwide annually [1]. This creates added costs in the cocoa manufacturing process, mainly linked to the added weight that CBS represents during cocoa bean transportation and the environmental and economic cost of its disposal or underutilization. Caffeine and theobromine were reported to possess several other beneficial properties for human health, such as anticarcinogenic, diuretic, and antiobesity effects, among others [2]

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