Development of black fungus-based 3D printed foods as dysphagia diet: Effect of gums incorporation

With the aging population trend, there is a great demand for dysphagia diet as the elderly suffering from dysphagia is increasing rapidly. 3D printing is capable of processing mashed and not attractive dysphagia diet into appetizing foods with appealing appearance. Black fungus (Auricularia auricula) illustrates many health-promotion effects, but its elastic texture and great chewing efforts making it unfeasible for the elderly. In this work, we studied the feasibility to develop 3D printed visually appealing texture modified black fungus-based food as potential dysphagia diet, with addition of gums (0.3%, 0.6%, 0.9%, w/w), i.e. k-carrageenan gum (KG), xanthan gum (XG) and arabic gum (AG). Results indicated that KG and XG addition significantly increased the mechanical strength (yield stress and elasticity), viscosity, hardness and gumminess of ink samples by reducing water mobility and facilitating hydrogen bond formation, while AG addition showed an opposite effect. International dysphagia diet standardization initiative (IDDSI) tests indicated that AG and KG containing sample failed the spoon tilt test within IDDSI framework, while XG containing sample could be classified as level 5-minced and moist dysphagia diet. 3D printed samples using control or AG containing ink illustrated poor self-supporting capability. KG containing ink was not easy for extrusion with defective points in printed samples. In contrast, XG-0.9% samples demonstrated high printing precision with great self-supporting capability and smooth surface texture. This work provides insights for the development of visually appealing dysphagia diet using 3D printing.