Effect of frying conditions on shrinkage and porosity of fried potatoes

Apparent density, true density, specific volume and internal porosity were investigated during deep fat frying of french fries. The effect of frying c onditions (oil temperature, sample thickness and oil type) on the above pro perties was examined. A simple mathematical model was used to correlate the above properties with oil and moisture content. Five parameters with physi cal meaning were incorporated into the model: the enclosed water density rh o(w), the enclosed oil density rho(L), the dry solids density rho(s), the d ry solids bulk density rho(bo) and the volume shrinkage coefficient beta'. Moisture and oil content during deep fat frying and consequently all the ex amined properties are affected by frying conditions. The results showed tha t the porosity of french fries increases with oil temperature increases and sample thickness and it is higher for products fried with hydrogenated oil . (C) 2000 Elsevier Science Ltd. All rights reserved.