Studies Of Different Treatments On Mechanical Property Of Fruits And Vegetables During Their Storage

This study was conducted on the difference of firmness, apparent modulus of elasticity, quality and rheological property of peach fruit during its low-temperature storage to determine the effects of cold shock treatment, heat treatment and γ-radiation. The relationship between the rheological parameter (including stress relaxation parameter and creep parameter) and other mechanical parameters and quality parameters such as firmness, apparent modulus of elasticity, sugar content and value of PH were established in this paper. This study is of great referential importance to research and practice in the storage of fruits as peach and tomato. The major results are as following:The study was to determine the effects of different treatment on the firmness, apparent modulusof elasticity, sugar content and value of PH. Cold shock treatment and γ-radiation with dosage of0.3kGy could restrain the decrease of firmness and apparent modulus of elasticity during the storage and had no disadvantage effect on the sugar content and PR The two treatments improved the quality of peach fruits. While, these parameter decreased significantly after the peach fruitswere heated or radiated by γ-radiation with dosage of 1.0kGy. Two different γ-radiation methodshad no significant effect on the sugar content, but had significant effect on the value of PH.The effects of different treatments on the compression coefficient, degree of elasticity and lag loss were also determined in this paper. Compression coefficient and degree of elasticity increased and lag loss decreased significantly after cold shock treatment. The other way round, compression coefficient and degree of elasticity decreased and lag loss increased significantly after heat treatment and γ-radiation with dosage of 1.0kGy. The γ -radiation with dosage of 0.3kGy had nosignificant effect on the three parameters.The stress relaxation tests were carried out and four parameters named as decay modulus, the equilibrium modulus, time of relaxation and specific viscosity in the relaxation model were obtained. The effects of different treatments on the stress relaxation parameters were determinedin this paper. The analysis results indicate that the cold shock treatment and γ-radiation treatment with dosage of 0.3kGy could increase the relaxation parameter during storage. Heat treatment and γ-radiation treatment with dosage of 1.0kGy made the parameters decreased.