Abstract
The changes in the quality of the yams stored in the field in Tokachi were investigated from November 1986 through April 1987. The soil air surrounding the yams was 2-4 fold richer in CO2 concentration than air during storage. However, there were no significant differences in the CO2 and O2 concentrations for soil air from 20 to 80cm depth. The viscosity of the ground solution of the yams decreased during storage, while a decrease in the rigidity was not observed. The spinnability increased gradually during storage. Multiple regression analysis revealed that the soil temperature significantly affected the viscosity of the yams at 1% level, whereas the CO2 and O2 concentration in the soil had little effect on it. Thus the viscosity could be expressed as a function of the temperature at the 60cm depth.
