Study On Theory Basis Of Chinese Jujube Quality Grade Division

Our country is the largest productive country and unique export country of Chinese jujube. With the development of jujube industry, entrying WTO and global agricultural products trade activition need a current dealing language-jujube product grading standard linking with international. It has an important practical significance to formulate reasonable jujube product quality grade standard to make jujube producement merchandize and standardize to enhance whole jujube industry level, strengthen market competition power, solve product quality dispute, accelerate internal and external trade activition and enhance buying and selling efficiency.Using excellent fresh Z.jujuba cv. Dongzao and dehydrated Z.jujuba cv. Jinsixiaozao, Wuhexiaozao, Zanhuangdazao, Xingtangdazao, Pozao, Yuanlingzao, Neihuangbianhesuan, Xinjianghuizao and Fupingdazao, appearance target -fruit size's distribution in different managemegt level orchards was probed basing on investigation results of main product district of Z.jujuba cv. Dongzao and Jinsixiaozao.grading condition of Z.jujuba cv. Dongzao main product district was analyzed. Reasonable specifications of various grades jujube product were determined. It supplies clear and feasible theory basis and practical operation basis for jujube product quality and grade judging. Another appearance target --area of red color setting of Z. jujuba cv. Dongzao was analyzed basing on investigation results. Area of red color setting was determined, both guaranteeing quality and beneficial for storage. The numbers of defect fruit was counted and tolerance of it was determined. Physics and chemistry target of jujube was studied. The results were as follows:1 Soluble solid content decreased with days after picking increasing, grades reducing and area of red color setting decreasing.2 Flesh-firmness increased with grades reducing and decreased with area of red color setting increasing on the whole.3 Edible percent decreased slightly with grades reducing. It had no apparent regularity change with area of red color setting increasing. It had a little high in well-management orchards. But it had no large difference.4 Moisture content decreased with grades reducing, with area of red color setting increasing and management level decreasing.5 Total sugars content increased with grades and area of red color setting increasing and management level reducing. Various trending of total sugars and that of sucrose wasidentical. Reducing sugars had a smaller variation.6 Among different grades Z.jujuba cv. Dongzao, acid content of substandard fruit was highest, that of superfine was higher and that of second-grade fruit was lowest. Among different area of red color setting Z.jujuba cv. Dongzao, acid content of whole -green was highest, that of one-half was higher and that of flush were lowest. Among different management level orchards, acid content of Z.jujuba cv. Dongzao in well-management orchard was lowest, that of medium and poor mannagement was similar and high relatively.7 Among different grades Z.jujuba cv. Dongzao, ratio of sugar to acid of first-grade was highest. Among different area of red color setting Z.jujuba cv. Dongzao, that of whole red fruit was highest. Among different management level orchards, that of Z.jujuba cv. Dongzao of poor management was highest.8 Among different grades Z.jujuba cv. Dongzao, vitaminC content of superfine was highest. Among different area of red color setting Z.jujuba cv. Dongzao, that of whole red was highest. Among different management level orchards, that of well-management orchards was highest.9 Per fruit weight of dried red jujuba is divided into 5 grades according to probobility grading; Moisture content of Z.jujuba cv. Jinsixiaozao and Wuhexiaozao was determined lower than 28%. The one of large jujube was lower than 25%. Edible rate and total sugars content of dried red jujube were determined bigger than measured lowest value. Acid content of dried red jujube was determined lower than measured highest value.