Study On The Production Technology Of Blacked Jujube(Ziziphus Jujuba Mill.)and Characteristics Of Composition Variation

Blacked jujube was made of red jujube by curing with controlled temperature and humidity,its taste,nutritional value function has new changes.Based on the changes of cAMP,5-HMF,polyphenols,total acid,reducing sugar and other contents in the aging and blackening process of jujube,this project optimized the influencing factors of the processing technology of jujube: blackening temperature,blackening time and water addition,and obtained the optimal production technology of blacked jujube.The changes of color,sugar components,total acids,polyphenols,5-HMF,cAMP and organic acids in the blackening process of jujube were tracked and analyzed.The results were as follows:(1)The processing technology of blacked jujubeRed jujube was processed into blacked jujube under different conditions of blackening temperature,blackening time and water addition.The results showed that the optimum technological conditions of the blacked jujube were: the blackening temperature was 75℃,the blackening time was 55 h,and the water content was 25%.Under the best conditions,the blacked jujube was fragrant,sweet and sour.The contents of each substance(dry matter)were cAMP 0.0137 g /100 g,5-HMF 0.103 g/100 g,polyphenols 2.71 g /100 g,total acid 17.09 g /kg,and reducing sugar 76.7 g /100 g,respectively.(2)The characteristics of the main components in the blackening process of jujubeThe changes of color,sugar components,total acids,polyphenols,5-HMF,cAMP and organic acids in 0-96 h of mellowing were tracked.The results showed that the color of jujube changed from red to black after mellowing,and the color change was mainly concentrated in the first 12 hours.With the extension of blackening time,reducing sugar in jujube showed an overall increasing trend,with the highest content reaching 74.5g /100 g.Fructose content increased rapidly from 22.6 g/100 g to 30.6 g/100 g between 0 and 60 h.The content of glucose increased most obviously from 0 to 48 h.The content of polysaccharide increased from 3.984g/100 g to 8.256 g/100 g during the whole blackening process,increasing by twice.Sucrose content continued to decline and disappeared 24 hours later.The contents of total acid,polyphenols and 5-HMF in jujube increased with the extension of blackening time.The total acid increased from 8.82 g/kg at the initial 0 h to 24.05 g/kg at 84 h.Polyphenols increased the most rapidly at 0-48 h in the early stage of mellowing,and the content reached the highest2.32 g/100 g at 60 h,1.5 times higher than that at 0 h.The 5-HMF content of red jujube increased rapidly to 3.52 g/100 g after 96 h blackening treatment.The content of cAMP decreased sharply during melanization from 0.41 g/kg to 0.14 g/kg at 96 h.Oleanolic acid gradually decreased from 122.6 mg/kg to 14.6 mg/kg,a decrease of nearly 90%.Ursolic acid showed the opposite trend,increasing from 81.1 mg/kg at 0 h to 158.3 mg/kg at 24 h,and reaching 181.2 mg/kg at 96 h,with a content increase of 2 times.The final content of betulinic acid changed little.This subject systematically studied the processing technology of blacked jujube and its composition change characteristics,innovated the deep processing method of red jujube,and laid a foundation for exploring the blackening mechanism of red jujube and the further application and development of blacked jujube.