engleski

Extraction of polyphenols using water-two-phase systems

Polyphenols are one of the most numerous and wide spread group of compounds in the plant world. In biological systems polyphenols (flavonoids) have an important role, which is attributed to their ability of binding free radicals, activation of antioxidant enzymes and inhibition of the oxidases. Nowadays, organic solvents such as methanol, ethanol, acetone, dimethylformamide, ethyl, acetate, diethylether are mainly used for the extraction of polyphenols. Those solvents require special process conditions and special care for disposal of used solvents. In this paper, extraction of polyphenols from the model solution was performed using water-two-phase systems which contains 70 % water and represents slightly burden on the environment. Aqueous solution of gallic acid was used as a model solution of polyphenols. Extraction was performed in aqueous-two-phase system containing PEG6000 - H2O - (NH4) 2SO4. The influence of the process parameters, the concentration of gallic acid, pH and composition of water-two-phase system was investigated to maximize distribution coefficient. A method of multifactor experimental planning was used to optimize extraction process and the results were statistically analyzed using the evolutionary operation method (EVOP). Optimal operating conditions of the extraction process were pH = 6.50, γ (gallic acid) = 4.50 g L-1, mass fraction of polyethylene glycol w(PEG) = 0.1037 and mass fraction of ammonium sulfate w (AMS) = 0.0925. At those conditions maximal distribution coefficient of K = 5.54 was achieved.

polyphenols; gallic acid; aqueous two-phase systems; multifactor plan of experiments; evolutionary operation (EVOP)

Ovaj se tekst temelji na radu koji je financirala Nacionalna zaklada za znanost, visoko školstvo i tehnologijski razvoj Republike Hrvatske.