Consumer's demand for functional food is a trend of the last decades. Nowadays, the attention is focused on the development of products with health claims on the label, which can result in value-added products for the producers companies. Cookies are popular staple foods in the human diet in many countries and are generally well accepted by consumers due to their sensory attributes, long shelf life and convenience. The incorporation of solid components on the biscuit dough, such as dietary fibre, could have serious implications on its structure and perceived texture which explains the technological limitations for the fibre incorporation. The aim of this work is to develop an enriched functional biscuit with Psyllium fibre and understand the impact of the new ingredient on physicochemical and sensorial properties of the dough and biscuits. The optimum biscuit's formulation was determined using the response surface methodology (RSM). Effects of wheat flour (48-52 %) and Psyllium (3-9 %) contents on the dimensional features (spread ratio, expansion factor), water activity, colour parameters (L*, a*, b*), texture characteristics (firmness, adhesiveness, cohesiveness, springiness) and sensory properties (colour, flavour, texture, overall acceptability) of dough and biscuits were investigated. The most representative parameters evaluated were used to develop biscuits with similar features to commercial references. An optimum formulation was obtained by incorporating 6 % Psyllium and 50 % flour. This biscuit has the enough amount of Psyllium soluble fibre recommended by Food and Drug Administration (FDA) to prevent the risk of coronary heart disease and to bear a health claim on the label.
Keywords: Commercial biscuits; Dietary fibre; Response surface methodology.