Effect of pre-treatment on viscoelastic behaviour of potato strips Original Research Article

The viscoelastic behaviour of french fries during deep fat frying after two different types of drying pre-treatment (air drying and osmotic dehydration) was examined under uniaxial compression tests. The stress-strain data of the compression test were modelled using a simple mathematical model, containing parameters such as the maximum stress (σmax), the maximum strain (εmax), the elasticity parameter (E) and the viscoelastic exponent (p). The effect of air drying duration and the type of osmotic solution used on the compression behaviour of fried potatoes was introduced through the corresponding effects upon the model parameters. Pre-fry drying as well as osmotic pre-treatment increase the maximum stress and maximum strain of french fries during frying. Air drying pre-treatment increases the crispness of potato strips while osmotic pre-treatment does not affect it, with the exception of sugar solutions.