Effects Of Different Drying Methods On Soluble Sugar And Sucrose Metabolism Of Hami Jujube

Crisp ripe full red Hami jujube was subjected to low temperature(40?,45?),sun drying and the in the shade drying,respectively,and physicochemical and liquid chromatography methods were used to follow the related changes in the dried products,including the water content,total soluble sugar,reducing sugar,titratable acid,sucrose metabolism and related enzyme activity;The dynamic model of total soluble sugar and reducing sugar was established,and the influence of different drying methods was evaluated on the sucrose metabolism.Following results are obtained(1)The changes of reducing sugar content in different drying processes showed a gradual upward trend;the total soluble sugar content decreased with the increase of drying time.The hot air drying at 40?and 45? had significant effects on the change of soluble total sugar content(P<0.05).Artificial low temperature hot air drying had inhibitory effect on the accumulation of titratable acid,especially in the middle of dry season;the ratio of sugar to acid was One of the main factors affecting the flavor of jujube fruit,the effect of different dryness on the ratio of sugar to acid in the drying process was significant(P<0.05).Different dry systems have the greatest impact on the pre-drying period.When the ratio of sugar to acid is about 35,it shows better sensory quality;during the drying process of 45? hot air drying and natural drying conditions,the sugar acid is kept relatively stable for about 35g/100g,the sensory evaluation is the best,and the flavor is also better than others.(2)Under the different dry test,the dynamic change data of reducing sugar and soluble total sugar were obtained by nonlinear fitting of Origin 9.1,and the fitting degree of the dynamic model of soluble total sugar content was higher than that of reducing sugar.The dynamic changes of soluble total sugar in jujube reducing sugar and hot air dried red jujube in the two natural drying processes were in accordance with the exponential model(first-order model);the dynamic change of soluble total sugar in natural dry jujube was in accordance with the log-fitting model;The dynamic change of soluble total sugar in dry jujube accords with the cubic fitting model;the dynamic change of soluble total sugar in hot air drying at 45? accords with the exponential model(zero-order model).(3)Under different dry test conditions,the change of sucrose content showed a trend of decreasing with the increase of drying time.The hot air drying at 45? had the greatest effect on the glucose content,and the hot air drying at 45? significantly increased the rate of conversion of sucrose to glucose.The difference in fructose and glucose changes was not significant(P>0.05).The enzyme activity of the same enzyme under different drying conditions lasts for different times;different enzymes have different enzyme activities under the same dry conditions.The drying temperature is low and lasts for a long time.During the drying process,the activity of sucrose invertase and sucrose synthase is relatively high,which promotes the conversion of sucrose into reducing sugar.