Inhibition Of 1-MCP Combined With Chitosan Coating On Strawberry Softening Mechanism During Cold Storage

Strawberry fruit is delicate,sweet and sour,and contains a variety of nutrients,which is deeply loved by the people.However they are easy to ripen and soften after harvest,and lose their commercial value.In this paper,Fragaria ananassa Duch Cv.'Hongyan' was used as material to study the effects of 0.5 ?L/L 1-MCP combined with 1.5%(w/v)chitosan on the quality,cell wall components,eell wall degrading enzymes and regarding genes of postharvest strawberry fruit.1-MCP combined with chitosan coating can effectively reduce the weight loss rate and decay rate in strawberry fiaxit,significantly inhibit the decrease of firmness during cold storage,and delay the color change,whereas it has no significant effect on soluble solids and vitamin C.1-MCP treatment of strawberry increased the decay rate;chitosan coating strawberry was Iess effective than combination treatment.These results show that 1-MCP combined with chitosan coating effectively delays the softening and restraint decay of strawberry fruit.1-MCP combined with chitosan coating delayed the accumulation of water-soluble pectin,but had no significant effect on covalently bound pectin and ionical pectin,inhibited the accumulation of hemicellulose in strawberry fruit and delayed the degradation of hemicellulose.The results show that 1-MCP combined with chitosan coating could effectively inhibit the decomposition of cell wall structure in strawberry fruit.1-MCP combined with chitosan coating inhibited the increase in activity of cell wall degrading enzymes including PME,PG,Cx,and ?-Gal,thus maintained the cell wall structure of strawberry fruit.The gene expression trend of FaPME1 was contrary to activity of PME,and the gene expression trend of FaPG1 was consistent with activity of PG.The results show that the inhibition of PG by 1-MCP combined with chitosan coating delayed the decomposition of cell wall structure.In conclusion,1-MCP combined with chitosan treatment delayed the degradation of cell wall components,especially pectin,by inhibiting the activities of PG and PME,and inhibit the softening of postharvest strawberry fruits during cold storage.This study provides theoretical and experimental basis for strawberry texture regulation and fresh-keeping technology innovation.