Rheology and Amylase Resistance of Calcium-Enriched Calorie-Dense Emulsions for Dysphagia Management

This study examines how changes in salivary α-amylase and calcium affect the rheological properties and stability of food emulsions thickened with Locust Bean Gum (LBG) and Pre-gelatinized Rice Flour (RF), containing 10% Medium-chain Triglycerides (MCT). Increasing the LBG: RF ratio improves resistance to simulated saliva dilution. The 1:4 (LBG: RF) emulsion maintained an apparent viscosity within the NDD nectar-like range after simulated saliva addition, making it suitable for patients with dysphagia. Calcium sources from lactate (LC) and gluconate (GC) enhanced the emulsion's resistance to α-amylase degradation, especially at a shear rate of 10 s^-1. The study also evaluated levels according to the International Dysphagia Diet Standardisation Initiative (IDDSI). Both NDD honey-like and pudding-like samples were classified as IDDSI Level 3 by the syringe test, showing that different grading systems and food compositions can lead to variations. After simulated saliva treatment, the 1:4 (LBG: RF) sample showed the least degradation. These findings highlight the significant role of salivary α-amylase in thickened foods and emphasize the importance of optimizing thickener types and formulation ratios to enhance dietary safety for individuals with dysphagia.