Effects of drying methods on changes of Vc,reducing sugar and total acidity in Chinese jujube

The changing regularities of Vc,reducing sugar and total acidity in the process of drying Chinese jujube were studied.The results showed that while drying Chinese jujube with natural method,the Vc content reduced rapidly,and merely dried for two days its loss rate would be higher than 90%.The reducing sugar content increased gradually and total acidity decreased when natural drying time extended.While drying Chinese jujube with far-infrared radiation or hot air,the contents of Vc,reducing sugar and total acidity reduced gradually in whole drying process.Analysis of variances indicated that two types of drying methods affected significantly the changes of Vc and total acidity,but not significantly the changes of reducing sugar.The drying temperature and time affected significantly changes of Vc,reducing sugar and total acidity.While drying Chinese jujube with vacuum freezing,the content of Vc,reducing sugar and total acidity reduced less.