The effect of a variable initial pH on the structure and rheological properties of whey protein and monosaccharide gelation via the Maillard reaction

The effects of varying the initial pH from 5 to 9 on Maillard reaction-induced whey protein gel formation and structural and rheological properties were determined. The molecular mass of whey protein and reducing sugar conjugates increased according to SDS-PAGE determination. Amino and surface sulphydryl groups were decreased, contributing to gel network formation. The amide I and II bands at 1640 cm(-1) and 1550 cm(-1), respectively, were decreased and the amide III peak at 1200-1300 cm(-1) increased, indicating the amino groups were participating in complex cascade reactions and the Maillard reaction during gel formation. Fluorescence measurements revealed that exposed tryptophan residues could increase the hydrophilic properties of the glycosylated protein. Gels formed from whey protein + glucose and from whey protein + xylose at an initial pH of 5 and 7, respectively, had a higher elastic modulus (G '), which was related to increased beta-sheet and random coil formation after the Maillard reaction. (C) 2020 Elsevier Ltd. All rights reserved.

Automated summary

The study found that varying the initial pH affected the Maillard reaction-induced whey protein gel formation, structure, and rheological properties. Decreased amino and surface sulphydryl groups contributed to gel network formation. Gels formed under different pH conditions exhibited varying elastic modulus and structures.