Production and Gastric Digestion Simulator Evaluation of <scp>3D</scp> ‐Printed Gel Foods With Hybrid Layered Structures

ABSTRACT The digestive characteristics of 3D‐printed foods have attracted considerable attention. However, the knowledge of the physical disintegration of 3D‐printed food induced by gastric peristalsis is insufficient. This study aimed to produce 3D‐printed foods with hybrid layers of different mechanical characteristics and to evaluate gastric digestion behavior using a gastric digestion simulator (GDS) that simulates gastric peristalsis. Two types of mashed potato‐based food ink containing 1.0 or 3.0 wt% agar were 3D‐printed in eight layers using a syringe‐based printer to form 12 mm cubes. Uniform and hybrid structures were produced by using one ink throughout or switching inks between top/bottom two and middle four layers. The average values of the produced four types of 3D‐printed foods ranged as follows: weight, 1.84–1.89 g; width, 12.40–12.57 mm; depth, 12.01–12.34 mm; height, 12.63–13.02 mm; fracture force, 2.1–7.8 N; fracture strain, 19.3%–27.6%; and brittleness, 0.3–3.0 N. The GDS digestion experiment revealed that the soft layers of the hybrid 3D‐printed foods were disintegrated in preference to the hard layers by simulated peristalsis. The digesta were classified on 0.60–3.35 mm sieves. The ratio of particles in the largest 3.35 mm fraction ranged from 22.4%–36.5% among the 3D‐printed foods. Most of the particles remaining in this fraction of 3D‐printed foods with hybrid structures were indicated to be derived from the hard layer. The GDS digestion experiment showed that the soft layers of the hybrid 3D‐printed food were disintegrated by simulated peristalsis in preference to the hard layers. This study provides fundamental knowledge that will lead to the advanced control of gastric digestion through the use of 3D food printers.