The Cupuacu (Theobroma Grandiflorum) fruit. High performance liquid chromatographic determination of antioxidant phenolic substances in cupuacu seed powder

A method for the qualitative analysis of antioxidant phenolic substances in cupuacu seed powder by high performance liquid chromatography is described. We have used n-exhane to degrease the cupuacu seed powder and a methanol-water (80:20) solution for the extraction of the analytes. HPLC separation was carried out by using a binary gradient elution utilizing methanol-acetonitrile 1:1 (v/v) and 0.5% (w/v) phosphoric acid. Spectral scans were continuously collected in the range 210-370 nm and the spectrophotometric chromatogram was plotted at 280 nm. Spectrofluorimetric detection was carried out with excitation at 280 nm and emission at 330 nm. Epicatechin and quercetin were identified by comparing the chromatographic behaviour and the UV spectrum of the extracted components with those of pure standards, while the spectrofluorimetric detection, by stopped flow technique, has allowed the identification of catechin and has confirmed the spectrophotometric identification of epicatechin.