Some Rheological properties of packaged grape tomatoes in the storage

Packaging films are one of the common ways to maintain the quality of food and agricultural products. The effect of PVC and HDPE packaging films, storage and temperature on some mechanical properties, including: the firmness force, yield strain, energy of rupture and modulus of elasticity and also, the viscoelastic behavior of the strawberry fruit was investigated. The mechanical test and relaxation test were done using a texture analyzer. In this study, the stress versus time graph was plotted and three-component Maxwell model coefficients were obtained. According to the results of this study, the use of these films had a positive impact on the yield strain. On the other hand, products in the packaging films were able to store products until the 40th day. In this study, the firmness force of HDPE packaging fruits in 4℃ and 20℃ from 2.17 to 1.10 N, 2.16 to 1.85 N, decrease respectively, during storage. The results show that Maxwell model (RMSE<0.6818 and R2 >0.9158) fits the experimental data. Also, with a retention time, the elastic component of the model is relatively reduced and the application of the packaging prevents the decrease in relaxation time.