Oxidative browning of melanoidin. II. Relationship between the molecular weight and the color intensity of color components of melanoidin from the glycine-xylose system.

Abstract

The molecular weights of color components (designated as P1, P2, P3, P4, P5, P6, P7 and P8 in order of elution from a DEAE-cellulose column) isolated by the conversion of color components of melanoidin produced from the glycine-xylose system in an oxidative browning were studied in relation to the color intensity. The molecular weights of P5, P6, P7 and P8 estimated by gel filtration on Sephadex G–50, G–75 and G–150 using dextran as a standard were approximately 2,140, 3,550, 5,600 and 14,200, respectively. The molecular weights of P1, P2, P3 and P4 could not be estimated by the gel filtration method because of their low values.On the other hand, a linear relationship between Kd, the distribution coefficient in dextran gel, and E450 (E) of the color components was observed. Thus, there is considered to be a linear relationship between log E and log molecular weight (M). The correlation coefficient between log E and log M was calculated to be from 0.96 to 0.98 in the visible wavelength region. Therefore, t...