Effect of mechanical treatments on creep behavior of potato tubers

The effect of surface type and angle, drop height, and number of impacts on the creep behavior of Lady Rosetta potato cultivar was studied. Instrumented sphere (impact recording device) was used to obtain the coefficient of restitution and to calculate the absorbed energy for steel sheet, steel rods, rubber-coated steel rods, and two-layer potato surfaces. The four-element model (Eo, Er, ηo, and ηr) was used to simulate the creep behavior of samples. Results showed that there is significant effects of drop height, surface angle, and number of impact on the creep parameters (P < 0.05). Higher parameters values, i.e. lower incident strain, were associated with steel rods and steel sheet surfaces, dropping tubers from 100 cm, and dropping tubers for 5 and 10 times. Moreover, the two-layer potato surface was found to cause the lowest strain values to the dropped tubers compared to other tested surfaces. Non-linear regression analysis was conducted between the absorbed energy and creep parameters. Low regression performance was obtained for Eo, ηr with determination coefficient (R2) best values falling in the range of 0.40-0.69, while Er and ηo showed fair regression. Results of this study could be used for improving storage facilities of potatoes by accurately estimating the strain affecting stored tubers and consequently the appropriate height such that strain values in the bottom layers do not negatively affect quality and shelf life of potato tubers.