Study On Mechanism Of Cell Wall Metabolism And Biological Preservation Technology Of Cold-Storage Loquat Fruit

Loquat (Eriobotrya japonica Lindl.), a popular fruit with juicy, tasty and nutrient-rich properties, is one of the most important economic fruits in southern area of China. The harvest season of loquat always accompany with high temperature and high humidity, which result in the short storage life. Low temperature storage is widely used to extent loquat storage life, however, it always leds to some physiological disorders including stuck peel, firmness and juiceless, and internal browning after several weeks, which are regarded as chilling injury symptoms. Therefore, it is crucial to elucidate the mechanism of the chilling injury of loquat and exploit the preservations for the fruits during cold storage. In this paper, we studied the mechanism of polysaccharides metabolism in cell wall related with leatheriness in loquat fruit; the effects of1-MCP on the major physiological disorder caused by flesh leatheriness, and the effects of the bio-preservation on the loquat fruit during cold storage; which aimed to extend the loquat fruit preservation. The results were as follows:Aimed to clarify the mechanism of the leatheriness of loquat fruit in low temperature storage, the cell wall polysaccharide metabolism of ’Jiefangzhong’ and ’Wugongbai’ fruit were compared. After30days’ storage,’Jiefangzhong’ exhibited significant chilling injury symptoms, while no obvious symptom was observed in ’Wugongbai’. However, the changes in polysaccharide contents of the loquat fruit of both cultivars revealed that the polysaccharides metabolism in loquat fruit significantly differed from other fruits. During the cold storage, the WSP contents decreased, the contents of CSP and SSP increased in both cultivars; the molecular weight of CSP and HC2upshifted. These phenomena indicated the cells were more close bound and the linkage between pectin and hemicellulose were more tightly, which result in loquat fruit leatheriness.The effects of1-MCP treatment on reducing chilling injury in cold-stored loquat fruit and the possible mechanisms involved were investigated.1-MCP treatment inhibited the increases in fruit firmness, AIR yield, lignin content, CSP content and SSP content, inhibited the decreases in cellulose content; besides,1-MCP treatment also inhibited the upshift of molecular weight of CSP and HC2. These results indicated that1-MCP treatment could significantly alleviate the lignification in loquat fruits.The effects of bio-preservation on loquat cold storage were also studied. The results showed that the fruit treated with bio-preservation had lower firmness, MDA content and lignin content, meanwhile, it can maintain the relatively higher quality than CK, the treatment fruit had lower rot rate, higher content of TSS and TA, and more intact peel. These results showed that the preservation could significantly alleviate the chilling injury, delay the metabolic rate, and keep nice shape and out-look.