Degradation kinetics of vitamin C in Chinese jujube during drying process

Abstract

In order to investigate the effects of drying temperature on the vitamin C in Chinese jujube and provide reference for the drying process, the degradation kinetics of ascorbic Acid (AA) and dehydroascorbic Acid (DHAA) at 50, 60 and 70°C has been investigated. The results showed that the loss of AA at different drying temperatures followed the Weibull model and all the correlation coefficients (R2) were higher than 0.99. The kinetic model of DHAA well fitted its degradation in Chinese jujube. Both AA and DHAA in Chinese jujube decreased during the drying process, however, the degradation rates of DHAA was lower than that of AA and its activation energy was higher than that of AA, these results indicate that DHAA in Chinese jujube was more stable than AA in thermodynamics. The kinetic modal can be used to predict the concentrations of vitamin C during the drying process of jujube.