The Chemical Composition And Antioxidant Activity Of Jujube

Jujube (Ziziphus jujube Mill.), one of our traditional fruits, is a good tonic with strong nutritive and health care abilities. In recent years, along with peoples' improving consciousness about health care, jujube is increasingly popular among customers. Most reported researches focused on the chemical composition and antioxidant activity of several varieties of jujube. However, chemical composition between different jujube varieties, or different mature period of one specie is different. Therefore, it is necessary to investigate the chemical composition and antioxidant activity of jujubes with different varieties and the different mature stage, in order to provide some references for the quality evaluation and classification of jujube, as well as provide a theory basis for the harvest time confirmation according to different utilization purposes of jujube products.Researches on chemical composition and antioxidant activity of Shanxi JiShan BanZao among three different mature periods and 16 Chinese jujube samples. In our study with the mainly conclusions as follows:1. Chemical composition in red jujube of different mature stage is different. In the mature process of red jujube, contents of water, total acid, total phenol and flavonoids content reduced gradually, while amounts of soluble solids, soluble protein and reducing sugar increased gradually. Content of Vc showed a trend of decrease after a slight increase.2. Along with the mature period of red jujube from white-mature stage to full red stage, amounts of total phenols and flavonoids of free state, ester bonding state, glycosidic bond state, as well as those in insoluble phenols were decreasing. Phenolic acids for quantitative analysis in these four polyphenol compounds mainly existed in red jujube with white-mature period and decreased along with the mature red jujube.3. Among the 16 national red jujubes, TaiGu HuPingZao and YanChuan jujube showed apparent advantages in longitudinal sizes and weights according to the current dried jujube grading standards in our country. Compared with other samples, QingJian jujube contained higher contents of soluble protein, soluble solids and reducing sugar. RuoQiang jujube has the highest solid acid, FuPing jujube and HeTian jujube have the highest content of Vc.4. In the 16 red jujube samples, LeLing gold thread jujube contained the largest amounts of individual phenolic acids that having already been known with the value of 1610.49 ?g/g DW. Protocatechuic acid, p-hydroxy benzoic acid, chlorogenic acid and rutin were the main phenolic compounds of red jujube, while the contents of cloves acid and hesperidin were low. Among the four polyphenol compounds, parts of F3 and F4 showed strong clearance rate of DPPH free radicals. Parts of F2 and F3 in S5 sample showed the highest scavenging ability of DPPH free radicals. In addition, the highest value of FRAP in the four parts phenolic compounds of JiaXian jujube was observed.