Development of soy protein emulsion gels-based 3D printed dysphagia foods: Effects of the egg white protein supplementation

Dysphagia diets are typically pasty and less appealing, yet 3D printing offers a solution to create more attractive foods. Soy protein isolate (SPI) is a promising protein source, however, emulsion gels with high SPI content (17%) are unsuitable for 3D printing due to higher yield stress and lower loss modulus. This study aims to enhance the 3D printing performance of SPI-based emulsion gels by modulating the SPI to egg white protein (EWP) ratio, specifically for developing dysphagia-friendly foods. The emulsion gels added with EWP had higher amino acid scores, improving protein absorption efficiency. When the EWP content increased, the printing performance improved, and the emulsion gel added with 30% EWP showed the best printing behavior, which was attributed to the appropriate reduction in apparent viscosity and mechanical properties. Additionally, the microstructure of the emulsion gels was loosened with higher EWP ratios due to decreased hydrophobic interactions, covalent bonds, and hydrogen bonds. According to the International Dysphagia Diet Standardization Initiative (IDDSI), the emulsion gel added with 30% EWP was classified as a level 5 dysphagia food. It contained 22% protein, meeting the high-protein food standards stipulated by the National Food Safety Standard General Rules for Nutrition Labeling of Prepackaged Foods in China, and exhibiting an amino acid score of 92.35. Thus, based on the nutrition values, printing performance and IDDSI tests, the emulsion gel added with 70%SPI and 30%EWP is recommended for preparing dysphagia food by 3D printing. This research provides novel insights into developing high-protein dysphagia diets using 3D printing.