Stress relaxation of dates at khalal and rutab stages of maturity

The viscoelastic nature of eight date cultivars at their khalal (balah) and rutab stages of maturity were studied by estimating their relaxation parameters from experimental stress relaxation data. Three popular stress relaxation models, namely the generalized Maxwell, Nussinovitch, and Peleg were fitted to experimental data. All three models were valid for quantifying the relaxation behavior of dates; however the generalized Maxwell was the best in predicting experimental data.