Extraction and purification of capsaicin from capsicum oleoresin using an aqueous two-phase system combined with chromatography

•A capsaicin yield of 95.5% was obtained from capsicum oleoresin in an aqueous two-phase system consisting of EOPO/ K2HPO4.•A capsaicin recovery and purity of 83.7% and 50.3%, respectively, were obtained for the separation using ADS-17 resin.•A capsaicin recovery and purity of 88.0% and 85.1%, respectively, were obtained for the separation using AB-8 resin. Capsaicin was extracted from capsicum oleoresin using an aqueous two-phase system (ATPS) composed of an ethylene oxide-propylene oxide (EOPO) copolymer, salt and ethanol. Capsaicin was concentrated in the top polymer-rich phase. To determine the optimal conditions, the partitioning of capsaicin in the ATPS was investigated, considering a single-factor experiment including the salt concentration, polymer concentration, buffer pH, ethanol concentration, sample loading and extraction duration. Response surface methodology was applied to investigate the effects of the polymer concentration, buffer pH and sample loading on capsaicin partitioning. A capsaicin yield of 95.5% was obtained using the optimal extraction system, which consisted of 16.3% UCON 50-HB-5100/10% K2HPO4/1% ethanol, a buffer pH of 4.35 and 0.24g of capsicum oleoresin. Capsaicin was purified from the capsaicinoid extract using a two-step macroporous adsorption resin (MAR) method. After purification using non-polar MAR ADS-17, the recovery and purity of capsaicin were 83.7% and 50.3%, respectively. After purification using weakly polar MAR AB-8, the recovery and purity of capsaicin were 88.0% and 85.1%, respectively.