The objective of this study was to develop a biscuit containing reduced fat and sugar levels as well as exhibiting 'functional' properties. A basic short dough formulation was used as a control. An experimental design was utilised to optimise the levels of Novelose 330 (resistant starch), Raftilose (sugar replacer/fructooligosaccharide), sodium casemate (dairy protein) and Simplesse (protein-based fat replacer) in the production of a functional low fat and sugar biscuit. Parameters measured were dough -characteristics, biscuit dimensions, colour, and texture. Sodium caseinate was found to be an important determinant for dough hardness. A positive correlation was revealed between biscuit thickness and texture (P < 0.01). Colour values L* (surface colour) ranged from 41.1 to 52.2, depending upon the quantities of sugar and protein powder present. Optimal ingredient levels were found to be 14% Novelose (% flour), 14.51% sodium caseinate (% flour), 25% Raftilose (% sugar) and 25.02% Simplesse (% fat). Such levels produce a biscuit of extremely high standard. (C) 2002 Elsevier Science Ltd. All rights reserved.