CHEMICAL AND CONFORMATIONAL CHANGES OF OVALBUMIN DUE TO THE MAILLARD REACTION

Abstract
Ovalbumin freeze-dried with or without the addition of glucose was stored at 50°C and 65% relative humidity to study the effect of the Maillard reaction on the chemical properties and conformational composition of ovalbumin. About 70% of available lysine in ovalbumin reacted with glucose before denaturation. The solubility and heat stability of the protein-glucose complex increased with the addition of the hydrophilic group and the repulsion force due to changes of such charged groups. During prolonged storage the changes of charge balance promoted the unfolding of ovalbumin at the expense of α-helix without the loss of β-structure. Insolubilization of the complex was accompanied by the high loss of lysine and arginine residues, brown color development and the formation of aggregates which were not cleaved by SDS plus 2-mercaptoethanol.