Development of gelling properties of inulin by microfluidization

In this paper, we report the impact of a microfluidic device (Microfluidizer^®) on the development of gelling properties of inulin – water systems. Inulin dispersions at a concentration of 2, 7 and 15%, w/w, were subjected to microfluidization treatments at 30 MPa with various numbers of circulations in the apparatus (1, 2 or 5 passes). The high shear stress treatment did not induce a chemical composition change of inulin. However, it allowed an increase of the gel-like behavior of the system as well as the viscosity of the inulin dispersion, transforming a visual aspect of the product similar to milk, to a system similar to yogurt or margarine depending on the concentration and the number of passes in the Microfluidizer^®. The viscosity increased with both the number of passes and the inulin concentration. Granulometry as well as optical and electronic microscopy ascertained the reduction of the particle size and the formation of a network composed of agglomerates which interacted with the solution and thus led to textural modifications.