Original scientific paper                                                                                                                                                         DOI: 10.17508/CJFST.2018.10.1.13

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


1Josip Juraj Strossmayer University of Osijek, Faculty of Food Technology Osijek, Department of Applied Chemistry and Ecology, Franje Kuhača 20, 31000 Osijek, Croatia
2University of Zagreb, Faculty of Chemical Engineering and Technology, Department of Analytical Chemistry, Marulićev trg 19, 10000 Zagreb, Croatia

Article history:
Received: 12 February 2018
Accepted: 20 February 2018
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. Adsorption process of phenolic acids and β-glucan was favored and chemical, and was best described by the pseudo-second order model.
phenolic acid,