Curcumin Interaction with Pea Albumin, Glutelin, and Globulin Protein Fractions: Impact on Physicochemical Properties, Microstructure, and In Vitro Gastric Digestion

Abstract

Pea protein fractions (albumin, glutelin, and globulin) were investigated for the influence of their interaction with curcumin on in vitro gastric protein digestibility. Dynamic light scattering analysis showed a decreased average particle size of the protein (0.25 mg/mL)/curcumin (2–100 μM) combinations. Turbidity and surface hydrophobicity analyses suggested the protein/curcumin complex formation via noncovalent interactions. Transmission electron microscopy revealed the formation of spherical nanocomplexes for albumin and globulin fractions and sheet-like structures for glutelin fraction with curcumin. Furthermore, curcumin did not alter the protein profiles, but at high concentration (100 μM), it differentially decreased the degree of hydrolysis of albumin, glutelin, and globulin by 76.6, 100, and 58.6%, respectively, indicating that the nature of the nanocomplexation hindered pepsin accessibility for protein hydrolysis. Therefore, this study enhances our understanding of how interactions between biomolecules in nanodelivery complexes and nutraceutical formulations influence the nutritional quality of plant-based proteins.