Effects Of 1-MCP And CO₂ Treatments On Quality Changes Of Fresh-cut Apples During Storage

In order to effectively improve the quality of fresh-cut apples and prolong shelf life,the effect of 1-MCP and CO2 treatment on fresh-cut apples was tested firstly;secondly,the feasibility of the combination of the two methods was discussed,and the mechanism of their effects was preliminarily studied;finally,the carbon dioxide damage early warning equation of fresh-cut apples was established,the results were as follows:1.The quality dynamics model of each quality index was established,and the quality decay dynamics equation under each index was established by combining with Arrhenius equation.Secondly,the browning index was determined as the quality index to characterize carbon dioxide damage of fresh-cut apples through correlation analysis,and the carbon dioxide damage early warning equation described below was established.The equation can be used to predict the remaining time of carbon dioxide injury symptoms in fresh-cut apples stored at 5-35 C.SL=93.24-f(t)/10748.27×exp(-1894.4/T)2.The effects of different 1-MCP concentration on the quality of fresh-cut apples showed that 1-MCP treatment could effectively prolong the shelf life of fresh-cut apples.Among them,1-MCP treatment with 1.5 ugl/L concentration and 24 h treatment time was the best treatment concentration for fresh-cut apples,which could prolong shelf life for 2 days.3.In the experiment of the effect of different CO2 treatment concentration on the quality of fresh-cut apples,it was found that 1-2%CO2 treatment concentration improved the browning phenomenon of fresh-cut apples and prolonged the shelf life of fresh-cut apples for 2 days,but when the CO2 concentration exceeded 2%,fresh-cut apples were more vulnerable to carbon dioxide injury,and reached the end of sensory score on the second day.4.In the experiment of using 1-MCP and CO2 to treat fresh-cut apples at the same time,it was found that 1-MCP treatment reduced the tolerance of fresh-cut apples to carbon dioxide,and when the concentration of carbon dioxide was 1-2%,the symptoms of carbon dioxide injury would occur.5.The study on the mechanism of the above phenomena showed that 1-MCP treatment made fresh-cut apples more prone to produce free radicals and other active components in the environment of lower carbon dioxide concentration,thus increasing superoxide anions and other components,increasing the activity of lipoxygenase(LOX),seriously destroying the membrane lipid oxidation defense mechanism of cells,and activating the activities of various defense enzymes.Sex,in turn,increases the permeability of cell membranes,relative conductivity,and produces a large number of harmful substances such as malondialdehyde,resulting in browning.In addition,1-MCP treatment was more likely to activate the activities of polyphenol oxidase(PPO)and phenylalanine ammonia lyase(PAL)in fresh-cut apples,which accelerated the formation of phenolic substances and quinones and black polymers,making fresh-cut apples very prone to browning.