EFFECT OF TECHNOLOGICAL PARAMETERS ON TOTAL SUGAR CONTENT OF RED JUJUBE DURING HOT-AIR DRYING

Previous researches about red jujube have focused largely on hygienic components, pharmacology and processing technologies, with little effort being made to investigate the changes and losses of nutritional ingredients during processing. Studying the effect of technological parameters on jujube's total sugar content during the drying process is helpful to rate the quality of the dried red jujube. In this study, Jujube, a type of red dates produced in Alar, Xinjiang, is experimented at different drying temperatures, air speeds and relative humidities by using a circular hot-air drier that is one of the most widely used drying machines. The results show that: drying temperature, air speed, relative humidity and their quadratic terms have significant effect on total sugar content of the dried jujube. The combination of the optimal technological parameters is: drying temperature 57.99 degrees C, air speed 1.54 m/s and relative humidity 39.14%. When the red jujube reaches its safe moisture content, the maximum total sugar content is 71.07%. Our experimental results provide a theoretical basis for optimizing the drying process.