Whirling bed blanching of potato cubes and its effects on product quality

A new technique of modified fluidized bed called whirling bed was adopted for blanching of potato cubes as the large particles (>4 mm) cannot be effectively fluidized by conventional fluidized bed as well as by spouted bed. Whirling bed blanching was accomplished by passing a saturated mixture of hot air and steam through a cylindrical column fitted with a semicylindrical wedge at its base on distributor plate for partial air restriction. The blanched product quality was compared with that obtained by hot water and steam blanching in terms of enzyme inactivation, solid loss, moisture content and retention of nutrients like ascorbic acid and reducing sugar. Rate of loss and diffusivities of ascorbic acid and reducing sugar were also studied. It was observed that whirling bed blanching (at 85 °C) required less time and resulted in higher retention of solids and nutrients as compared to hot water and steam blanching.