Establishment of 3D Structuring of Resistant Starch

Abstract

Inkjet printing technology has been applied to the fabrication of food products with high precision/resolution and minimal material waste. This technique has been applied only to materials with low viscosity because of mechanical limitation. And, it has been challengeable to build 3D structure of food with high resolution for high viscous food materials. In this study, using an ink‐jet‐type, drop‐on‐demand (DOD)‐based piezo‐electric jet printer, RS2 type resistant starch, which is known as “rigid and not easy to build 3D structure”, is laminated and structured to verify the possibility of 3D structuring of resistant starch. Raw potato starch (RPS) was utilized as the RS2‐type resistant starch material, and cellulose nanocrystals (CNC) and sodium alginate (AS) were used as the structural materials for RS2‐type resistant starch lamination. First, RPS (0%, 1%, 3%, and 5%) was added to the CNC and AS mixture to analyze rheological properties, 3D printing, precision, and physical properties. The mixed ink of CNC, AS and RPS will be named CAP. For rheological properties, a frequency sweep was performed within the range of 0.01 to 16 Hz. The CAP ink according to RPS content exhibited shear‐thinning behavior and was easily extruded from the nozzle during 3D printing. The value of G' indicated maintained shape of the structure in the range of 1133.51 to 1326.27 Pa. During 3D printing with the same CAP head parameters, the pressure range of CAP ink extrusion differed depending on RPS content. The CAP with 5% RPS was in contact with the nozzle during printing due to the high pressure. In piezo‐electric jet printing, the precision of the RS2‐type resistant starch 3D structure was affected by pressure. Hardness increased as RPS content increased. This study showed that 3D lamination of RS2‐type resistant starch material was possible up to 3% RPS, demonstrating the possibility of developing 3D resistant starch food products using an inkjet piezo‐electric jet printer.