INFLUENCE OF SOME PROCESSING AND STORAGE CONDITIONS ON THE MECHANICAL PROPERTIES OF OAT FLAKES

Flake breakage and texture are important quality criteria in oat flakes. These properties are determined by themechanical properties of the flakes, which may be influenced by process variables such as kilning and flake thickness. A pindeformation method was used to measure the rupture force of individual oat flakes at different water activities. The monolayervalue of ground oat flakes ranged from 5.83 to 6.84 g/100 g dry matter. Thick flakes were strongest, requiring 3.4 N to rupturethe flake compared to 2.2 N for the thin flakes. Water softened the flakes, causing a decrease in rupture force from 3.6 N to2.4 N as water activity increased from 0.115 to 0.848. Kilning had a significant effect on flake thickness but not on themechanical properties. This study suggests that oat flakes should be stored at water activity 0.4 or less as there is a sharp lossof flake strength above this point.