Studies On Softten, Senescence And Physiological Changes Of Jinling Jujube During Storage In Microporous Membrane

Jinling jujube is a feature breed which widely planted in Chaoyang,Liaoning province recent years.The jujube fruit is big,sweet-sour dense,rich in nutrition and extremely good in fresh eating-quality,receives consumer's good graces.But Jinling jujube is liable to liquor-producing,soften,putrefaction and deterioration after picking,which may cause enormous losses if coming into the market once in a short period.Therefore,it is a key problem in industrialization development of jujube that prolongs fresh jujube storage life and supplies market continuously.This research used Jinling jujube with its three maturation at more half red,half red and little red jujube as its research materials,determined their ice points respectively to inference optimum storage temperature.We determined respectively O₂ and CO₂ concentration in different fresh-keeping film during storage,accounted redden and crisp date rate of jujube, according to storage effectiveness to ensured optimum fresh-keeping film.We stored three maturation Jinling jujube in microporous membrane at 0±0.5℃,determined index changes of hardness,reducing sugar,titratable acid,soluble solid,PPO activity,POD activity,relative conductivity,MDA,PG activity.The main result showed that:1.The ice point of little red jujube is -1.83℃,the ice point of half red jujube is -2.76℃and the ice point of more half red jujube is -3.55℃,so that the optimum temperature is about 0℃.2.Microporous membrane is optimum to store Jinling jujube.The concentration of CO₂ is keeping below 2%in fresh-keeping film during storage to defer redden and soften time with crisp date rate of jujube keeping above 80%.3.The fruit hardness of Jinling jujube reduces with the storage period extending.The high ripeness,the lower the hardness,the high the ripeness,the bigger the decrease amplitude during storage.There is evident positive correlation between fruit hardness and Vc content,its correlation coefficient is 0.944,the fruit hardness has significant negative correlation with POD activity,its correlation coefficient is -0.937. 4.The high ripeness when jujube fruit harvesting,the easier jujube fruit senescence and browning.When stored at 96th day,nutrient component of more half red jujube loosed most, the half red jujube next,little red jujube least.PPO activity of more half red jujube is most, the next is more half red jujube,little red jujube least,with their numerical value is respectively 7.28â–³420nm/min·g FW,6.21â–³420nm/min·g FW and 4.73â–³420nm/min·g FW. The POD active peak of more half red jujube appears at 48th day,the half red jujube appears at 72ed day,the little red jujube appears at 84th day.The relative conductivity of more half red jujube is 63.91%,the half red jujube that is 54.29%and the little red jujube 48.43%,the high ripeness,the bigger the relative conductivity.The MDA content of more half red jujube ascends 4.4μmol/g FW,the half red jujube that is 4.18μmol/g FW and the little red jujube 3.36μmol/g FW during storage.5.The sugar-acid ratio of half red Jinling jujube is 39 when the 96th day,which ripeness is closest approach jujube fruit harvesting,so that the flavor and character is best.6.PG is one of the key enzymes which affects jujube fruit soften.PG active peak appears with the beginning of jujube fruit soften.There is significant negative correlation between fruit hardness and PG activity during storage,the correlation coefficient of more half red jujube is r=-0.901,the half red jujube is r=-0.929 and the little red jujube is r=-0.910.7.The more half red jujube is suitable to sell at once or short-term storage after picking, which can't bear storing.The storage property of half red jujube and the little red jujube is good,but the weightlessness rate of little red jujube is high correspondingly,and the flavor is not very good,so the half red jujube is suitable to store chronically.