Study On Fresh-keeping Effect Of Xinjiang Winter Jujube With Different Coatings

Winter jujuba（Zizyphus jujuba cv.Dongzao）is one of the special agricultural products in Xinjiang.Winter jujuba has gradually become a excellent product in Xinjiang in recent years due to its rich nutritional value and unique sensory qualities.However,the shorter storage period and rapidly decreasing quality which greatly damage the commerciality of postharvest winter jujube.At present,domestic and foreign researches mostly focus on the storage by low temperature and chemical treatment,while the research on coating film preservatives is relatively small.Preservative coating film treatment can effectively prolong the storage time and quality of fruits and vegetables,so it is of great significance to research the coating film storage and preservation technology of winter jujube.This subject takes Xinjiang winter jujube as the main raw material,and studies the effects of different preservatives on the storage quality,ethylene and active oxygen metabolism of winter jujube to provide the theoretical basis.The main research contents and conclusions of this article are as follows:1.Through the preliminary research,the optimal 1-MCP concentration and natamycin+chitosan concentration were determined that were 1.0μL/L 1-MCP,1%natamycin+0.2%chitosan.Different treatments have certain freshness-preserving effects on the sensory quality of winter jujube,which can significantly inhibit decay rate and weight loss rate,maintain the higher hardness,reduce the respiratory rate and release rate of ethylene,but it has no significant impact in color change.When stored for 60 days,the winter jujube decay rate was 11%,weight loss rate was 2.10%,hardness was 12.87 kg/cm²,color difference value was 20.02,respiratory strength was 7.25 mg/kg?h,ethylene release rate was 0.0035μL/kg?h.Comprehensive analysis showed that 1-MCP+chitosan+natamycin composite coating film had the best fresh-keeping effect on winter jujube.2、Different treatments have a certain maintenance effect on the nutrient content of winter jujube,which can delay the reduction of TSS,TA,Vc,flavonoids,total phenols,polysaccharides,etc.in winter jujube fruit.When stored for 60 days,TSS content was 33.38%,TA content was 0.18%,Vc content was1.91 mg/g,flavonoid content was 33.51 mg/g,total phenol content was 5.84 mg/g,and polysaccharide content was 2.08.mg/g.Through comprehensive analysis,the treatment with 1-MCP+chitosan+natamycin composite coating can maintain the active components of winter jujube better,and the effect is the best.3、Different treatments have a certain regulating effect on the active oxygen metabolism of winter jujube,which can significantly increase the activities of SOD,CAT,POD,APX enzymes,inhibit the production of superoxide anions,and delay the increase and accumulation of H₂O₂,thereby delaying the senescence of winter jujube fruits.When stored for 60 days,the optimal H₂O₂ content of winter jujube was1.78μmol/g,O₂^—production rate was 0.25 nmol/g?min,SOD activity was 69.38μmol/g?min,CAT activity was 1.61 mgH₂O₂/g?min,POD activity was 0.84 OD₄₇₀/g?min and APX activity was 43.81 U/g.Comprehensive analysis shows that the treatment of winter jujube with 1-MCP+chitosan+natamycin composite film has the best effect on the regulation of active oxygen metabolism.