MICROWAVE AND WATER BLANCHING OF CORN KERNELS - CONTROL OF UNIFORMITYOF HEATING DURING MICROWAVE BLANCHING

Corn kernels were blanched in water and by microwave. The blanching ef ficiency was measured by four parameters; the thermolability of solubl e peroxidase (POD), of two insoluble isoforms (membrane-bound and cell ulose-bound POD) and of soluble protein. Using a water-shield model to improve the uniformity of heating by microwave and to control the rat e of heating, microwave blanching was significantly more efficient as measured by all four parameters when blanched at 85C. There was no sig nificant difference in the POD isoform heat-stability when blanched at 70C by the two methods. POD insoluble isoforms were more heat-stable than the soluble isoform. POD isoforms, occupying three cellular envir onments were more efficiently inactivated by uniform microwave heating compared to water blanching, demonstrating the viability of microwave blanching.