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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% K 2 HPO 4 /1% ethanol, a buffer pH of 4.35 and 0.24 g 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. [ABSTRACT FROM AUTHOR]

Abstract: In this research, the effect of cross-linked acetylated starch on the set yoghurt system was studied by investigating the flowability, viscoelasticity, zeta potential, conductivity and microstructure of the set yogurt system. The results indicated that the stability, elastic modulus (G′) and viscous modulus (G″) of the set yogurt system increased as the concentrations of cross-linked acetylated starch increased. The set yogurt system, which added the cross-linked acetylated starch, exhibited shear-thinning behavior and belonged to yield pseudoplastic fluid. The SEM micrographs demonstrated that the microstructures of set yoghurt were mainly composed by the network of casein. By adding cross-linked acetylated starch, the network of casein was strengthened, and both conductivity of the yoghurt system and particle size of casein micelles due to absorption of modified starch revealed the aggrandizement trend. It can be deduced that the starch adsorbs onto the surface of the casein micelle and this phenomenon prevents flocculation of the casein micelles owing to electrostatic adhesion, steric stabilization and osmotic effect. [Copyright &y& Elsevier]