Whey protein isolate-tamarind seed gum complexes stabilized dysphagia friendly high internal phase emulsions: The effects of pH conditions and mass ratios

Dysphagia is a common malfunction affecting a large population worldwide, yet the range of food available to the patients is limited. The objective of this study was to utilize a complex of whey protein isolate (WPI) and tamarind seed gum (TG) as novel emulsifiers to stabilize HIPEs, and further explore WPI-TG-based HIPEs' potential as dysphagia-friendly foods for special medical purposes (FSMP). The results indicated that WPI-TG forms complexes through hydrogen bonding and electrostatic interactions (pH 3 and 4). Additionally, TG induced changes in the secondary and tertiary structures of WPI. The particle size of HIPEs prepared from WPI-TG complexes was found to be reduced. Meanwhile, with the decrease in pH from 7 to 3, the variation in complexes zeta-potential led to an initial increase followed by a subsequent drop in the particle size of HIPEs. The rheological results indicated that WPI-TG-based HIPEs exhibit low-risk swallow characteristics, including shear thinning, high storage modulus, and good recovery ability. Further analysis using the IDDSI testing demonstrated that WPI-TG-based HIPEs under pH 3 and 4 can potentially be dysphagia-friendly FSMPs. After undergoing thermal treatment or long-term storage, WPI-TG-based HIPEs at pH 3 and 4 consistently maintained compliance with the IDDSI testing. These findings provided valuable insights for the future utilization of HIPEs in developing dysphagia-friendly FSMPs.