Maillard reaction of disaccharides with protein: suppressive effect of nonreducing end pyranoside groups on browning and protein polymerization

The Maillard reaction of ovalbumin and several disaccharides (maltose, cellobiose, isomaltose, lactose, melibiose) having glucose at the reducing end was investigated by measuring several properties of the sugar-protein Maillard adducts after each sugar was kept with ovalbumin at 50 OC and 65% RH for 0-20 days. Isomaltose and melibiose mixed with the protein strongly induced brown colorization, production of fluorescent compounds, and protein polymerization, whereas maltose, cellobiose, and lactose did so very weakly. All five of the sugars decreased free amino groups of the protein to less than 20% within 1 week. The weaker production of advanced Maillard reaction products such as brown color and/or fluorescent compounds in the maltose, lactose, and cellobiose systems indicated that the terminal pyranoside groups bonded at the C-4 OH of glucose retarded further degradation to aldehyde components of their Amadori rearrangement products. Earlier studies on the reaction between various reducing sugars and amino acids showed that the rates of the coupling reaction between amino and carbonyl groups and the browning reaction observed at advanced stages of the reaction were affected by the chemical structure of sugars and amino acids (e.g., Lewis and Lea, 1950; Pomeranz et al., 1962; Burton and McWeeney, 1963).