Analysis of printing temperature effect on texture modification: Potential of soy protein isolate-based bigel for swallowing-friendly food.

This work prepared the soy protein isolate (SPI)-beeswax-based bigel loaded with β-carotene, and the effect of printing temperature (PT) on texture regulation was investigated. During printing, increasing PT weakened the rheological properties and printability of ink. However, the mechanical strength and deformation resistance at non-linear regions of products were strengthened after printing. The more compact moisture binding state and stronger hardness and gumminess were found as PTs increased. Consequently, cold extrusion (PT at 25 °C) achieved the highest precision, and the product was classified as level-5 or level-6 minced and moist food under the International Dysphagia Diet Standardization Initiative (IDDSI) framework. Confocal laser scanning microscopy (CLSM) and Scanning electron microscope (SEM) showed that increasing PT might melt the beeswax-based oleogel and aggregate into larger particles during printing. After printing, the gathering particles would recrystallize and form the needle-like crystal with β/β' structure, as Polarized light microscopy (PLM) and X-ray diffraction (XRD) shown. This microstructure would provide the products with higher mechanical strength deliver β-carotene to the intestine and prolong the release behavior during digestion. This work provides new insight into achieving texture modification and tailoring high nutritional dysphagia diets by 3D printing.