4D printing of mashed potato/purple sweet potato puree with spontaneous color change

摘要

In this study, the effects of pH (2.5, 6.5 and 7.8) and potato flake content (15%, 19%, 23% and 27%) on the properties of mashed potatoes (MP) were studied in terms of moisture distribution, Theological properties, texture properties and 3D printing performances. Results showed that the potato flake content was positively correlated with apparent viscosity, storage modulus (G'), and loss modulus (G ''), while negatively correlated with tan delta and relaxation time (T-2). As the content of potato chips increased, the shape fidelity of MP increased after printing. The addition of citric acid increased MP's apparent viscosity, G', hardness and gumminess, thus increasing its capacity to be self-supportable performance after deposition, while an opposite trend was observed when sodium bicarbonate was added. A dual-extrusion printer was furtherly used to manufacture a colorful 4D ready-to-eat food in terms of spontaneous color change by using anthocyanin-rich purple sweet potato puree and MP. Results indicated that the color change of MP was significantly correlated with the pH value and the potato flake content.