The Studies Of Experiment And Theory On Modified Atmosphere Packaging For Tomato And Pea

Modified atmosphere packaging(MAP) is the one of the efficient and modern way to fresh-keeping the fruits and vegetables. The main principle for extending the shelf life is to automatically modify the composition of different gases in the package and to control the respiration rate by using the optimum plastic films. Nowadays in china the study for MAP has not been completed .Therefore it has a strong realistic meaning to study the MAP of fruits and vegetables.The research work mainly included as follows:(1)The experiment system was designed. The changes of the gases for the fruits and vegetables in MAP were studied in this paper. According to the Michaelis-Menten equation and Qua-item equation ,the parameters of the respiration model were got. The results showed the respiration rate in closed system was lower than that in flow-through system, the data from models and experiments were similar.(2)The gas exchange model for fruits and vegetables were built based on the Mass balance theory. The change of the gases composition and pressure in rigid package and the change of the volume and pressure in flexible package were analyzed. It showed the data from models and experiments were similar.(3)According to the attributes of products, the mathematical model of evaluating the quality of vegetables and fruits on the MAP was put forward by the method of the principal component analysis. The optimum gas composition were got finally. The results showed that the method of the principal component analysis was useful in analyzing the quality of vegetables and fruits on the modified atmosphere package and the results were reasonable.(4)The influence of different packaging materials packaging method and parameters have been studied too in the experimental way. It showed that the PE was the better film to maintain the quality of tomato , V_c,. weight loss and other parameters changed little. For pea, multi-film was the worst film and PE and CPP can maintain the quality similarly.(5)The MAP design method was carried out including analyzing the main factors and finding out the way of determining the film and original gas composition. Basing on the former experiments, MAP design for tomato and pea was done.