The kinetics of nutritional quality changes during winter jujube slices drying process

Abstract

The purpose of this research is to investigate the kinetics of nutrient quality (Vitamin C (Vc), reducing sugar and total acidity) change of winter jujube slices that under different drying temperatures (55, 60, 65 and 70?) and different air velocities (3, 6 and 9m/s) during the air-impingement drying process. Results showed that the content of Vc, reducing sugar and total acidity decreased with increasing drying time. Furthermore, analysis of variances indicated that the drying temperature, air velocity and time had a significant effect on the loss of Vc, reducing sugar and total acidity (p<0.05). Zero order, first order and Weibull models were used to fit the experimental data, Weibull model was considered as the most suitable one to the degradation kinetics of Vc, reducing sugar and total acidity in dried samples at different temperatures and air velocities. According to the Arrhenius formula, the activation energy of Vc, reducing sugar and total acidity degradation kinetics were 63.78 kJ/mol, 36.48 kJ/mol and 153.51 kJ/mol, respectively. This research can provide some references for enhancing dried products quality in the jujube drying industry.