Four different shapes of extruded snacks were purchased in a lo- cal supermarket. The shapes were selected based on the most com- mon types of snacks available on the market, which are cylindrical (Fig. 1A), pelleted (Fig. 1B), ring-shaped (Fig. 1C) and shell-shaped (Fig. 1D). Out of the eleven snack products purchased, three were cylindrical, three pelleted, two ring-shaped and three shell-shaped.
All cylindrical, ring-shaped and shell shaped snacks are made with corn flour, while pelleted snacks are made with wheat flour. Different raw materials to produce the snacks and different shapes were chosen precisely to involve a major variety of extruded snacks in this study.