New insights into morphing food through a semi-automated system for creating accurate surface grooves of varying depths on cereal-based snacks

Abstract

A new strategy for morphing food consisting of an automated system to generate highly precise grooves on cereal-based snacks with the aim to precisely control the shape changes triggered by baking treatments, has been proposed. The grooves altered the dehydration rate and shrinkage on the top and bottom surfaces, triggering the bending. The baking process was described by the Weibullian model (r > 0.99), with a rate constant between 0.00859 and 0.02066 g H₂O/g w.b.∗min in line with the increased groove depth. For thicker samples a delamination was observed for all the groove depths studied, due to the formation of gas pockets generated by water evaporation into the dough. In these cases, the control of morphing could not be achieved. Due to the inhomogeneous heating, delamination occurred mainly at the edge of the samples, as well described by the 2D X-ray cross-sectional images. Thinner samples (1.89 mm and 1.24 mm) achieved the desired shape change as groove depth increased; the swelling effect was not visually observed, while the microtomographic images showed slight swelling. It was possible to obtain a significant bending angle of 122° and 167° respectively after 20 min and 50 min of baking for a sample of 1.24 mm thick, 5.5 cm long, and groove depths of 900 μm.