The browning reaction of glucose-lysine system was studied to explain the accelerating mechanism of the reacting by phosphate or borate.
Intensities of color, fluorescence and ultraviolet absorption of the system increased in parallel with each other. Decrease of fluorescence did not occur even though the browning reaction was extended. The fluorescence of the system was supposed to be due to not only precursor of brown pigment but final products of the reaction.
Ultraviolet absorption spectrum of the system containing phosphate differed from the one containing borate. Borate induced the loss of the reducing power of glucose in the absence of lysine.
It was considered that phosphate may accelerate the browning reaction by its simple catalytic action. On the contrary, borate may possibly accelerate the reaction through the formation of its complex with sugar. One of the possible way of the reaction induced by borate is aldehyde formation by opening of pyranose ring, and another way is ketose (sorbose) formation.