Improvement of Thermal Stability of Fish Water Soluble Proteins with Glucose-6-phosphate through the Maillard Reaction

Abstract

Water soluble proteins (WSP) from the flesh of blue marlin Makaira mazara were modified through the Maillard reaction with glucose (G) or glucose-6-phosphate (G6P) by heating at 60°C for up to 12h. The development of brown color, loss of free amino groups, formation of fructosamine, and amount of bound phosphorus were determined. The Maillard reaction of WSP + G6P was found to progress faster than WSP+G. The incorporation of phosphorus into WSP took place mainly during the early stage of the Maillard reaction. From the results of SDS-PAGE analysis, it was revealed that the polymerization of proteins was also accelerated in WSP+G6P. Increasing phosphorus content of WSP brought about the improvements of solubility at pH above 7 and thermal stability of WSP. WSP modified with G6P at 60°C for 3 to 6h retained protein solubility more than 80% even after heating at 100°C for 10min.