Development of soft food gels from high-methyl pectin-protein conjugates via acid- and heat-induced crosslinking for dysphagia-friendly applications.

This study developed pea protein isolate (PPI)-high-methyl (HM) pectin conjugates via the Maillard reaction to enhance PPI's functionality as a texture modifier for dysphagia-friendly soft food gels. Conjugation at 1:1, 2:1, and 4:1 protein-to-pectin ratios significantly improved structural flexibility, physicochemical characteristics, and functional properties. Fourier Transform Infrared Spectroscopy (FT-IR) confirmed successful conjugation through shifts in amide I and II bands, while SDS-PAGE revealed higher molecular weight aggregates, indicating effective crosslinking. Circular Dichroism (CD) spectroscopy showed a reduction in β-sheet content (from 47.41 % to 16.15 %) and an increase in α-helices (from 0 % to 12.70 %), enhancing solubility (from 1.79 % to 100 %) and reducing surface hydrophobicity (from 74.52 % to 18.16 %). These structural changes facilitated improved protein dispersion and stable gel network formation, enhancing gel cohesiveness and softness, key attributes for dysphagia-friendly textures. Conjugate-incorporated gels exhibited softer textures than firmer control gels. Acid-induced gels formed soft, easily deformable matrices, while heat-induced gels produced firmer structures, accommodating different dysphagia severity levels. International Dysphagia Diet Standardization Initiative (IDDSI) assessments classified these gels as Level 6, ensuring safe swallowing. Rheological analyses revealed non-Newtonian shear-thinning behavior, while SAXS confirmed uniform nano-aggregation. Overall, PPI-HM pectin conjugates demonstrate potential as safe, functional solutions for texture-modified foods targeting dysphagia management.