A A C C   2 0 0 0   A n n u a l   M e e t i n g

To evaluate the effect of heating and freezing on beta-glucan isolated high molecular weight oat beta-glucan was subjected on heating from 60°C to 120°C at pH range 3...11. Same samples were also frozen and their molecular weight was analyzed after 1, 3 and 10 days and 1, 2 and 4 months frozen storage at -20°C. Also repeated freezing and thawing cycles were employed and the samples analyzed. Heating caused molecular weight to decrease as the temperature and the duration of heat treatment increased. More remarkable was the high stability of beta-glucan under alkaline condition were molecular weight decrease was less pronounced than at neutral pH. The higher buffer concentration had pronounced decreasing effect on molecular weight Frozen storage had no effect on molecular weight but repeated freezing/thawing cycles for five times had significant effect on molecular weight.