Abstract:The browning index，5-hydroxymethylfurfural（5-HMF）content，total phenol content，ascorbic acid content，free amino acid content，and reducing sugar content of Nanguo pear juice were determined during storage at different temperatures.The kinetic equation was fitted to reflect the status of each index so as to reveal the main mechanism and influencing factors of non-enzymatic browning.The results showed that the nonenzymatic browning of Nanguo pear juice were mainly caused by Maillard reaction and oxidative decomposition of ascorbic acid，while the oxidative condensation of polyphenol and caramelization had little effect on the browning.The changes in 5-HMF content and ascorbic acid content of the juice stored at different temperatures can be fitted with the zero-order reaction kinetics model.The non-enzymatic browning of Nanguo pear juice was accelerated with the increase in storage temperature.