Carbohydrate- or protein-based fat mimetics were used to replace up to 50% of fat in cookies. The effect of the type of fat mimetic and of the percentage of fat replacement on textural behaviour of the products was studied by compression tests. The stress-strain curves obtained were fitted by an exponential equation containing as parameters the maximum stress (sigma(max)), the maximum strain (epsilon(max)) and a viscoelastic exponent (f), A simple mathematical model for sigma(max) and the ratio sigma(max)/epsilon(max). indicative of hardness and brittleness of the cookies, respectively. vas developed. Both these values depended on the percentage of fat replacement and the type of fat replacer used. Hardness and brittleness of the cookies generally increased with fat replacement, but a moderate increase was obtained by some of the fat mimetics. resulting in products with better textural characteristics than their low fat, no mimetic-added counterparts. The viscoelastic exponent increased also with fat replacement and the model parameters depended on the type of the fat mimetic. (C) 2002 Published by Elsevier Science Ltd.