Heritability of polyphenols, anthocyanins and antioxidant capacity of Cameroonian cocoa (Theobroma cacao L.) beans

Abstract

This study investigates the heritability of polyphenolic, anthocyanin and antioxidant capacity of beans derived from four cocoa clones and their offsprings. These compounds were analyzed at 280 nm (polyphenols) and 520 nm (anthocyanins) by reversed-phase high-performance liquid chromatography (RP-HPLC) method using a photodiode array detector (PDA). The antioxidant capacity of methanolic extracts prepared from cocoa beans was measured by the DPPH and ABTS assays. Samples displayed catechin and epicatechin as the two main polyphenols. Epicatechin, which represents 1 to 5% of defatted cocoa seed powder, was hundred-fold higher than catechin while cyanidin-3-arabinoside was three-fold higher than cyanidin-3-galactoside. The two main anthocyanins found in our samples represent about 0.05% of defatted cocoa seed powder. All these compounds were genotype-dependent. Unidentified substances called A, B and C were also found in cocoa seeds. Substance A is discussed as a derivative of caffeic acid and an ester-bound compound. Substances B and C are oligomers of proanthocyanidins. Antioxidant capacity of cocoa beans obtained by 2,2'-azino-bis (3-
ethylbenzothiazoline-6-sulphonic acid (ABTS) assay was higher than those obtained by DPPH assay. According to correlation tests, flavanols contributed better in the antioxidant capacity than anthocyanin. No maternal effect was detected in the transmission of polyphenol compounds suggesting a nuclear heritability.

Key words: Theobroma cacao, cocoa beans, polyphenolic compounds, anthocyanins, heritability.