Application of D-optimal mixture design for the formulation of inulin-based fat replacers

The awareness and knowledge of the diet-disease consequences led consumers to make well- informed and healthier food choices selecting foods with reduced sugar, fat and salt. Indeed, there is increasing interest in improving the nutritional value of foods characterized by high level of cholesterol and fatty saturated acids, such as meat products. Animal fat reduction may result in the deterioration of the sensory and technological aspects of reformulated meat products, therefore, researchers focused on suitable ingredients able to substitute animal fat in meat products. Fibres have been widely used as fat replacers in cured meats, and among them, inulin has been tested as fat replacers in cured meat products showing prebiotic and gelling properties. Since the polymerization degree of inulin may have a significant influence on the rheological properties, in this study the optimization of the fat replacer was carried out considering two dinstinct D-optimal mixture x process designs, one for HDP inulin and one for LDP inulin. The aim was to optimize the amounts of inulin, water and guar gum to reach similar rheological properties of the beef fat. Frequency sweep tests highlighted an elastic-like behaviour of the inulin gels, with a dominant storage modulus (G’>G”) forming a structure type gel. Results from the shear rate ramp showed that inulin gels were characterized by a higher consistency index, compared to beef fat. The application of the D-optimal mixture design allows to find ranges of formulation with viscosity comparable to the control fat with potential application as fat replacer in low-fat hamburgers.