FIG. 1. Changes in color and viscosity of heat-processed koji (HP-koji). HP-koji was
heated at 55°C for 7 days, and the effect of incubation time on the color was observed
(A). HP-koji was sampled at 1, 3, 5, and 7 days after incubation. Browning and
liquefaction were expressed in terms of absorbance at 400 nm and viscosity,
respectively (B). Absorbance of koji before incubation was measured at 400 nm using
the same method as that used for HP-koji. The gray bars and open circles represent
browning and viscosity, respectively.