Calcium ion-regulated oil body-filled pea protein isolate-inulin emulsion gels for dysphagia-oriented products

The demographic shift toward an aging population is becoming increasingly pronounced. One consequence of this trend is an increase in swallowing and chewing difficulties among elderly people. This has driven the demand for specifically formulated foods that address dysphagia. This study investigated how different concentrations of Ca²⁺ affected the structural, water-holding, textural, and rheological properties of oil body-filled pea protein isolate-inulin emulsion gels. The aim was to assess their suitability as dysphagia-friendly foods. The results revealed a critical threshold for gel texture modulation via Ca²⁺, with 15 mM Ca²⁺ producing a dense honeycomb-like network structure, improved self-supporting ability, and enhanced water retention. Interactions between Ca²⁺ and functional groups (-OH and COO-) facilitated the formation of “calcium bridges”, which significantly increased gel hardness and cohesiveness. Rheological analysis and the International Dysphagia Diet Standardization Initiative (IDDSI) tests revealed that gel without Ca²⁺ exhibited the highest strain in the creep recovery test and could be classified as level 3 dysphagia foods. As the Ca²⁺ concentration increased, the gels showed higher viscoelastic modulus and lower yield stress, indicating a tendency toward brittleness. These modified gels corresponded to IDDSI levels 4–6. This study offers a theoretical foundation for the design of novel gel-based foods tailored to the specific swallowing needs of individuals with dysphagia.