High-Protein Hydrogels Composed of Pea-Collagen Protein and κ-Carrageenan for the Dysphagia Diet

In this study, pea-collagen proteins and κ-carrageenan were used to create hydrogels with high protein content (20%-27.5%) for dysphagia diets by varying the collagen concentration (7.5%-15%). The effects of collagen concentrations on physical, rheological, and textural properties; microstructure; suitability for a dysphagia diet; and the degree of proteolysis during in vitro digestion of hydrogels were explored. Temperature-sweep analysis indicated that collagen did not participate in network formation and behaved more like an inactive filler. For this reason, the amount of nonnetwork proteins increased with increasing collagen concentration. This caused high water-holding capacity (96.21%-99.75%), low hardness (1.58-1.82 N), and cohesiveness values. A higher collagen concentration in the hydrogel structure did not negatively affect the hydrogel's deformation, which was beneficial for the force required for food processing and swallowing, as well as for nutritional value. On the basis of the International Dysphagia Diet Standardization Initiative (IDDSI) framework, hydrogels were classified as Level 6, making them suitable for mild dysphagia. Collagen concentration only slightly altered the overall digestion pattern, whereas the degree of proteolysis at the end of the intestinal phase ranged from 55.08% to 65.67%. These findings provided new insights into the design and development of nutritious, palatable foods for people with swallowing difficulties. PRACTICAL APPLICATIONS: Hydrogels composed of pea-collagen protein and κ-carrageenan can be used in the diet of elderly people with dysphagia as a protein source, increasing food intake.