Fabrication of edible inks for 3D printing as a dysphagia food: An emerging application of bigels

With the increasing prevalence of swallowing difficulties among the elderly, 3D printing technology has emerged as a promising approach to create attractive and appetitive dysphagia diets. This study focused on synthesizing bigels composed of beeswax oleogel (OG) and gellan gum hydrogel (HG) to explore their potential for 3D printing dysphagia diets. The ratio of OG to HG plays a pivotal role in determining the gel network structure, rheological properties, and water distribution of the bigels, thereby influencing their suitability as 3D printing ink. Notably, a bicontinuous structure achieved with an OG to HG ratio of 1:1 (sample 1-1) imparted desirable properties for 3D printing, including moderate shear-thinning behavior, ensuring smooth extrusion, excellent thixotropy for maintaining structural integrity, and adequate storage modulus for self-supporting during printing. These were indicated by lower flow index (n value) of 0.18, longer time respond to the applied stress (λ value) of 9.51 ± 0.32 s, higher creep recovery rate of 55.51 ± 1.36%, thixotropic recovery rate up to 93.23 ± 0.72%, and uniform moisture distribution across semi-bound water and free water with ratio of 56.94 to 43.06, compared to bigels with OG-in-HG and HG-in-OG structures. Evaluation of the 3D printed bigels through the International Dysphagia Diet Standardization Initiative (IDDSI) confirmed that sample 1-1 (classified as Level 5-Minced and Moist) was suitable for individuals with swallowing difficulties. This study provides new insights into developing visually appealing dysphagia diet using 3D printing. [Display omitted] •3D-printed bigels are emerging as a promising application for dysphagia diets.•Micro/macro-properties of bigel can be modulated by adjusting oleogel-hydrogel ratio.•3D printing and swallowing properties are closely related to rheology of bigels.•Bigel with oleogel-hydrogel ratio of 1:1 is optimal for printing and swallowing.