Degradation kinetics of anthocyanin and physicochemical changes in fermented turnip juice exposed to pulsed UV light

Abstract

In this study, the effects of pulsed UV (PUV) light on the degradation kinetics of anthocyanins and physicochemical properties of turnip juice were investigated. PUV light was applied to turnip juice at 3 different distances (5, 8, 13cm) from the quartz window of the xenon lamp for 5 different times (5, 15, 30, 45, 60s). The pH, total acidity (% lactic acid), monomeric anthocyanin content, color density, hue, brightness, and percent color components (yellow, red, and blue) of turnip juice changed significantly after PUV-light treatments at each level. The maximum degradation of anthocyanin after PUV-light treatments was found to be about 63%. The anthocyanin degradation, brightness, yellow and blue color (%) increased, while red color (%) decreased with longer treatment time and shorter distance. The degradation of monomeric anthocyanins in turnip juice exposed to PUV light was described by the Weibull model (R-2 0.982-0.998, RMSE 0.087-0.133) more accurately than the first-order kinetics (R-2 0.906-0.992, RMSE 0.071-0.192).