engleski

An equilibrium and kinetic study of phenolic acids adsorption onto β-glucan

Phenolic acids belong to the group of natural polyphenols, which are secondary plant metabolites. Polyphenols show many positive bioactivities, which are not completely investigated. One of these bioactivities is the polyphenol interaction with food compounds, such as lipids, proteins, and dietary fibres. The information about the interactions between polyphenols and dietary fibres can be obtained through the parameters of adsorption equilibrium models, like Freundlich, Langmuir, Dubinin-Radushkevich, and others. Also, the reaction order and the kinetic constants can be obtained through kinetic models, like pseudo- first and pseudo-second order models. The objective of this study was to obtain information about the interactions between phenolic acids, like, p-coumaric and caffeic acid, and β-glucan as a natural dietary fibre, through non-linear adsorption models and kinetic models of the pseudo-first and pseudo- second order. The adsorption was carried out at 25 °C for 16 h, in a model solution which contained polyphenol, β-glucan, and phosphate buffer pH 5.5. Kinetics was conducted at 25 °C during 1, 2, 5, 10, and 16 h. After reaching the adsorption equilibrium, the un-adsorbed polyphenols were separated from the adsorbed ones by ultrafiltration. The non-linear adsorption equilibrium models and kinetic models were determined. The results showed that the adsorption was favoured and chemical process, and was best described by the pseudo- second order model.

adsorption ; kinetic ; phenolic acid ; β-glucan

nije evidentirano