Comparison and verification of respiratory rate models of Litchi under different storage temperatures

Abstract: Litchi is delicious, which is loved by consumers, But litchi is a fruit which is extremely not resistant storage. After a period of normal temperature, litchi is easy to browning and flavour. Litchi belongs to the respiratory strong fruit, Litchi can consume certain oxygen to produce carbon dioxide during respiration. Therefore, during storage, the concentration of carbon dioxide and oxygen directly affects the respiratory intensity of litchi. For the study of litchi respiration rate prediction model in this paper, "Guiwei" litchi fruit was chosen as the experimental material,at different temperatures (5, 10, 15, 20, 25 ℃) using a closed space system method to carry out the research on the respiration rate of Litchi, The nonlinear model, Michaelis-Menten model based on the principle of enzyme dynamics and multiple regression model for the prediction of the respiration rate of Litchi. The results show that among the three models, the multivariate regression model has the highest degree of fitting, providing a reference for the calculation of the respiration rate of litchi. The temperature has a certain influence on litchi respiration rate, the temperature rise will accelerate the respiration of litchi, low temperature contribute to the inhibition of respiration, Litchi during respiration rate decreased with time increasing, tends to a stable value, in the long run during the cold storage of litchi to keep low respiratory rate can effectively prolong the quality of litchi shelf life. Based on multiple regression analysis of litchi respiration rate, this paper fitted several respiratory rate models, and the fitting degree is high. The expression can provide reference for the calculation of litchi respiration rate. In order to compare the differences between different models, this paper verified the litchi each respiration model under 15 ℃, The fitting degree of the three models was greater than 0.92, which indicated that all the three models were suitable for calculating the respiration rate of litchi. There is a certain deviation between the predicted value of different respiration rate models and the actual calculated value. The relative error of Non-linear model P1 prediction value is ?10%-28%, The relative error of Michaelis-menten model P2 prediction value is ?14%-14% and the relative error of Multiple regression model P3 prediction value is ?10%~10%. The three models can to a certain extent show the relationship between respiration rate with time, the respiration rate decreased with time increasing, and finally tends to be stable, confirmatory experiments show that the relative errors of the models prediction values are small, The results showed that the multiple regression model could better characterize the litchi respiration rate model to a certain extent. The selection of the multiple regression model can more accurately reflect the actual respiration rate of Litchi and provide a theoretical basis for gas storage. The results show that the multiple regression model not only has a high degree of fitting, a small relative error, but also a more rigorous prediction trend, and the multiple regression model is suitable for the calculation of respiratory intensity of litchi.