study of changes in rheological properties of potato tissue during storage using the creep test

the changes in viscoelastic properties of potatoes (tubuls agria) stored at 4 ˚c for 4 months were modeled and evaluated by using the creep-recovery test. cylindrical specimens with 15 mm in diameter and 35 mm long were used. the samples were allowed to deform gradually under the constant stress (110 kpa) for about 30 min. after removing the load, the sample recovery was registered. deformation of the specimens with time were measured and recorded. strain-time curve was plotted for loading and recovery process. four-element (burgers) mechanical model adequately described the creep response of the potato tissue. the coefficients of instantaneous elasticity, elastic and viscous coefficients of the retarded elastic part, newtonian viscous flow and retardation time were determined, as they can be used to study the effect of storage conditions on the quality of the stored potatoes. these values were decreased significantly (p <0.05) as the storage time increased.