Drying Characteristics And Processing Technology Of Red Dates In Southern Xinjiang Based On Vacuum Drying

Chinese Jujube,one of the unique fruits in China,ranks first in the world in terms of yield over the years.At present,the drying methods of Chinese Jujube are high cost and long time,which have great influence on the quality of Chinese jujube products.In this paper,Xinjiang Junzao,Huizao and Dongzao were selected as the research object,aiming at the problems of the vacuum drying process,such as the optimal control of the drying rate and the quality of the dried jujube products,by using ORIGIN8.0software,the effects of single factors on the physical quality of Jujube during drying process were analyzed,and the best jujube variety for vacuum drying was selected,design-expert10.0 software was used to optimize the process of vacuum drying jujube,which provided reliable and powerful evidence for Jujube drying industry.The results showed that:(1)The Chinese date samples were dried under different drying temperatures(55 °C,60 °C,65 °c)and vacuum degrees(-0.6 bar,-0.7 bar,-0.8 Bar).The results showed that the drying time of Winter Jujube was longer and the drying rate of Grey Jujube was faster under the same drying conditions.When the vacuum degree is-0.8 Bar and the drying temperature is 65 °C,the drying rate of Jujube is relatively high.When the moisture content of Jujube reached the target moisture content,the dried jujube sample was cooled,and the color difference,rehydration ratio,texture characteristics and sensory quality of the Jujube sample were analyzed,the results show that when the vacuum drying temperature is 60 °C and the vacuum degree is-0.7 Bar,the best taste score is obtained and the best color difference is obtained at-0.8 Bar and55 °C Through comprehensive analysis,the optimum value of each index in three kinds of dried jujube can obtain the best drying quality,and the Jujube is most suitable for vacuum drying.(2)Through Design-Expert software,the color difference,rehydration ratio and adhesiveness of Chinese date were modeled,and the quadratic regression equation of each index was obtained.The resultsshow that the regression equation has a high fitting degree and is suitable for predicting and analyzing jujube varieties in vacuum drying process.Through the test of response surface and the analysis of the interactive factors,the optimum drying parameters of Grey Jujube are as follows: drying temperature is55 °C,the vacuum is-0.8 Bar(relative pressure is 80 KPA)and the moisture content is 27.25%.