Modification of the texture of 3D printing soy protein isolate-based foods with proper nozzle sizes: A swallowing oriented strategy for dysphagia diet.

3D printing could provide swallowing-friendly food with high nutrition for a dysphagia diet. The effects of printing nozzle size on texture modification were studied using the soy protein isolate (SPI)-beeswax (BWX)-based bigel ink system enriched with bio-actives. Smaller nozzle sizes (0.4 to 0.8 mm) decrease while bigger ones (1.6 to 2.0 mm) increase the texture profiles. Fortunately, the 1.0 mm nozzle size helps to regulate the rheology of mechanical strength and soften the texture of hardness, as well as maintain a higher proportion of semi-solid water. Consequently, the 1.0 mm nozzle achieved the highest printability and the product was classified as level-5 or level-6 minced and moist food. The decreasing nozzle sizes apply higher shearing force to the bigel ink, which leads to the aggregation of oleogel particles, crystal clusters, and the broken of the SPI hydrogel network. Increasing the nozzle sizes maintained structure stability but resulted in the fabrication of harder textures and slower release of bio-actives. The 1.00 mm kept the balance between the large and small nozzle effect, which might help to keep the microstructure stable and show high bio-accessibility of bio-actives. This work provides a novel insight into texture modification with 3D printing parameters.