Preliminary Explored The Mechanism Of Quality Changes Initiated By The High Temperature And High Humidity Air Jet Impingement Blanching

Jujube as a famous vegetable in Xinjiang is abundant and had good quality. The baking processing notonly prolonged the shelf life after picking but gave the unique flavor after processing. However, the bakingprocessing consumed a lot of time and labour force. High temperature and high humidity air jetimpingement blanching technology can increase process efficiency in the base of process quality assurance.The technology will supply a way for rapid process in Jujube.High temperature and high humidity air jet impingement blanching technology was applied to Chinesejujube produced from Korla in XinJiang in this paper. The content of this paper was to investigate theeffects of blanching temperature(105℃), diverse blanching relative humidity (30,40,50%) and blanchingtime (1,3,5,7min) on reducing sugar, total sugar, total acidity,5-HMF content and colour in Chinese jujubeof different initial moisture content (25,30,35%). The paper also optimized the process of blanching inChinese jujube. The main conclusions are as follwos：(1)The reducing sugar content of Chinese jujube in each points of blanching time increasedsignificantly as compared to the untreated Chinese jujube. The peak of reducing sugar increment movedforward with increasing blanching relative humidity in the same initial moisture content. In the sameblanching relative humidity, the peak of reducing sugar increment moved forward with increasing initialmoisture content of Chinese jujube. The time of reducing sugar content reached the peak was shortened asblanching relative humidity increased. The time of reducing sugar content reached the peak had positivecorrelation with energy blanching provided.(2)Total sugar and total acidity content in Chinese jujube of different initial moisture contentdecreased with blanching time in diverse blanching relative humidity. The5-HMF content in Chinesejujube of different initial moisture content rose with blanching time in diverse blanching relative humidity.(3)With the extension of blanching time, L*values dropped, A*and B*values rose in the sameblanching relative humidity and initial moisture content. With increasing the blanching relative humidity,L*values dropped, A*and B*values rose in the same blanching time and initial moisture content. Withincreasing the blanching time, L*values dropped, A*and B*values rose in the diverse initial moisturecontent and blanching relative humidity. With increasing the initial moisture content, L*values rose, A*and B*values dropped in the same blanching time and blanching relative humidity.(4)The red date with30%initial moisture content blanched by40%blanching relative humidity in4.5min is the optimized blanching process. The maximum reducing sugar content is45.15g/100g.