Influence of drying methods on cocoa (Theobroma cacao L.): antioxidant activity and presence of ochratoxin A

Abstract

This work aimed to evaluate the performance of different drying methods in the development of phenolic compounds, methylxanthines, and antioxidant activity in cocoa bean and to evaluate the presence of ochratoxin A (OTA). Antioxidant activity was determined using DPPH, FRAP, ORAC and β-carotene-linoleic acid assays. Phenolic compounds and methylxanthines were determined using high-performance liquid chromatography with an ultraviolet detector (HPLC-UV). OTA was determined by ultra-performance liquid chromatography with fluorescence detection (UPLC-FLR). It was found that during cocoa drying, there was a reduction in antioxidant activity with reduced phenolic compound content (0.04 mg.g^-1 of catechin before drying to 0.02 mg.g^-1 after drying) and reduced methylxanthines (19.44 mg.g ^-1 of theobromine before drying to 11.71 mg.g^-1 after drying). Only one sample showed contamination by OTA (7.1 μg.kg^-1). The traditional drying method showed the highest conservation of antioxidant activity and methylxanthine and phenolic compound content.

Keywords:
catechin; epicatechin; caffeine; theobromine; mycotoxin