Conjugation of Pea Protein Isolate via Maillard-Driven Chemistry with Saccharide of Diverse Molecular Mass: Molecular Interactions Leading to Aggregation or Glycation

Diverse saccharides are effectively grafted to pea protein isolate (PPI) through Maillard-driven chemistry. The development of conjugates (glyco-PPI) was validated by ultraviolet-visible spectroscopy, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and size exclusion chromatography-high performance liquid chromatography. The impact of covalent conjugation on color development, structural modification, solubility, thermal stability, and volatiles of glycoprotein was examined. The protein solubility was improved, while its thermal stability seemed to be negatively influenced. The principle proposed involves Maillard-driven generation of the conjugates, which enhanced the surface hydrophilicity and unfolding of protein architecture of glyco-PPI. Additionally, both molecular mass and the grafted number of saccharides played a vital role in determining the solubility and thermal stability of glyco-PPI. Protein tends to denature at reaction conditions of 80 °C and pH 10.0, and its cross-linkage occurred in the aqueous system. The two potential routes of molecular interactions between PPI and saccharides were denaturation and glycation or self-cross-linkage. Flavor profile alteration of glycoprotein before and after conjugation was depicted, and relevant off-odors were quantified via headspace solid-phase microextraction gas chromatography-mass spectrometry. These outcomes could furnish valuable in-depth information for dictating functionalities of plant-based protein for food application.