Abstract
Glucose and ribose cause browning in the presence of amino acid, and the browning reaction seems to be accelerated by inorganic phosphate. In this experiment, some glycolytic intermediates, hexose-phosphates and adenosine phosphates, were autoclaved in the presence of amino acid.
G6P, F6P and FDP produced brown color, but GIP, AMP and ATP did not produce any visible color. In general, sugar phosphates and adenosine phosphates liberated inorganic phosphate and lost sugar during autoclaving. However, the degrees of phosphate-liberation and loss of sugar were greater in G6P, F6P and FDP which produced brown color than in others. Adenosine phosphates which contain ribose caused no browning, although it liberated inorganic phosphate and lost ribose by autoclaving.
It is considered that the browning of hexose phosphates except G1P is introduced by the liberation of inorganic phosphate from sugar, being followed by the sugar-amino reaction accelerated by the catalytic action of inorganic phosphate. Thus, the possibility that hexose phosphates may be involved in some extent in the browning of fish flesh by heat must be considered, although their contents are lower than these of free sugars in fish flesh.
