Effects Of Coating Treatments On Storage Quality And Antioxidant Capacity Of Zizyphus Jujuba Miller Cv. Dongzao

To explore the relationships between antioxidants,enzymes and antioxidant capacity,reveal the changes of jujube quality after harvest,three different coating treatments were studied in Dongzao for the storage quality?firmness,weight loss,fresh fruit,soft fruit,red index,total soluble solid?TSS?and titrable acid?TA??,nutrients?vitamin C,polysaccharide and cyclic adenosine monophosphate?,secondary metabolites?total phenolics,total flavonoids,triterpenoids and proanthocyanidin?,malondialdehyde?MDA?,antioxidant enzymes?superoxide dismutase?SOD?,peroxidase?POD?,peroxidase?CAT?and ascorbate peroxidase?APX??activity and antioxidant capacity?FRAP,DPPH radical scavenging and ABTS radical scavenging?.The results showed the storage quality of jujube declined during storage.CaCl₂ and chitosan can efficiently inhibit the decrease of firmness,fresh fruit,TA and TSS,the increase of weight loss,soft fruit and red index.While the fruit treated with pullulan occurred turning red and softening in advance and the mature accelerated.Overall,the preservation effect of 2% CaCl₂ and 1% chitosan were better and CaCl₂ was the most significant?p<0.05?.CaCl₂,chitosan and pullulan treatments significantly slowed down the rate of secondary metabolites changes?total phenolics,flavonoids,triterpenes and proanthocyanidin?,significantly inhibited the declining of polysaccharide and cAMP and the production and accumulation of MDA?P < 0.05?.The secondary metabolites decreased quickly in control,but stable in treated fruit.MDA of control was significantly higher than that of treated fruit?p<0.05?.Results of antioxidant capacity showed CaCl₂,chitosan and pullulan treatments can maintain high enzyme activity and antioxidant activity of DPPH radical scavenging and FRAP in jujube fruit,but there was no significant effect on ABTS radical scavenging.TOPSIS and PCA analysis indicated the descending orders of preservation effects of coatings were as followed: 2% CaCl₂> 1% chitosan >1% pullulan.In general,the coating treatments can significantly inhibited the deterioration of storage quality,nutrients loss and declining of enzyme capacity to improve the antioxidant activity of jujube.Coatings is an useful and potential method for maintaining good sensory quality and nutritional values.