Prevention of thermal degradation of red currant juice anthocyanins by phenolic compounds addition

Abstract

The aim of this study was investigation of prevention of thermal degradation of the red currant juice anthocyanins by addition of different phenolic compounds (catechol, 4-methyl catechol, catechin, chlorogenic acid and gallic acid). Phenolic compounds were added in 50:1 and 100:1 copigment:pigment molar ratio. Red currant juice samples were heated at 30, 50, 70 and 90 °C for 1 hour. Thermal degradation of anthocyanins was investigated through determination of anthocyanin content and calculation of the reaction rate constant, half-life of degradation, activation energy and anthocyanin retention. Anthocyanin content ranged from 34.32 mg/100 mL to 47.97 mg/100 mL in a red currant juice, depending on temperature. When phenolic compounds were added anthocyanin content ranged from 34.94 mg/100 mL to 50.41 mg/100 mL, depending on both temperature and added phenolic compounds. In all cases when phenolic compound were added, anthocyanin content, half-lives of degradation increased and the reaction rate constants decreased. The thermal degradation of anthocyanins was lower when phenolic compounds were added due to copigmentation effect. With increase of temperature copigmentation effect was less pronounced. The most contributing phenolic compounds on anthocyanin stability at 30 °C was gallic acid, at 50 °C and 70 °C catechin, and at 90 °C 4-methyl catechol. Concentration of phenolic compounds also had influence on investigated parameters.