| In this paper,chitosan is used as the substrate,and the degree of crosslinking of the crosslinked chitosan film is controlled by controlling the proportion of epoxidized polyethylene glycol(PEGe)added in the crosslinking reaction.Observe the effect of different cross-linking degrees and film-forming conditions on film properties through gas permeability test,mechanical property test,etc.Taking Soak volume,PEGe ratio and immersion time as research variables,the best chitosan film-forming conditions were selected through single factor and orthogonal optimization experiments.The optimized cross-linked film was used in the fresh-keeping experiment of Nanguo pears at room temperature,and the effect of the coating on the storage quality of Nanguo pears was studied under both vibration and non-vibration treatments,in order to establish the best Nanguo pears cross-linked shell Effective method for keeping fresh with glycan coating.The research results are as follows:1.Material performance test results show that the addition of epoxidized polyethylene glycol(PEGe)improves the mechanical properties of the chitosan membrane,and the CO2/O2 transmission ratio is greatly improved,from the original 3.48 to 6.02.The cross-linked state is good.2.The best coating conditions for Nanguo pears are:chitosan concentration is 1.4%,epoxidized polyethylene glycol(PEGe)concentration is 0.85%,soaking time is 60s.The experiment proves that the preservative formulation has a good preservation effect.3.The compound coating film at the initial stage of storage reduced the respiratory activity of the fruit.In the later period of storage,the cross-linked CS/PEGe coating film also significantly reduced the weight loss rate,rot rate and malondialdehyde content of the Nanguo pears under the vibration and non-vibration treatments,and increased the Nanguo pear's hardness value and vitamin C content.Delayed the process of fruit senescence,thereby improving the nutritional value of the fruit. |
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