Effect of Maillard-induced glycosylation on the nutritional quality, solubility, thermal stability and molecular configuration of whey proteinv

Whey protein isolate (WPI) was subjected to controlled and limited Maillard-induced glycosylation using dextran. Maillard reaction was optimized to promote glycosylation, while minimizing browning and maintaining nutritional quality. Hydrophobic interaction chromatography was used to separate unreacted dextran from unreacted and glycosylated proteins, collectively termed as partially glycosylated whey protein (PGWP). Solubility and thermal stability of PGWP and WPI were compared over a wide range of pH, protein concentrations, and heating temperatures and times. Compared with WPI, PGWP maintained higher solubility and thermal stability at protein concentrations greater than 4.2%, over a wide range of pH, including the pH around the isoelectric point (pI) of whey protein. The enhanced solubility and thermal stability of PGWP was attributed to reduced intermolecular interactions. Several physico-chemical/structural changes, including resistance to denaturation, shift to more acidic pI, reduced surface hydrophobicity, reduced exposure of sulfhydryl groups, and unique glycosylation sites, contributed to the reduced intermolecular interactions. (C) 2012 Elsevier Ltd. All rights reserved.