Evaluation of microwave toasting of corn flakes

Abstract

During flake production, corn undergoes processes of cooking, drying, tempering, laminating, and toasting. The toasting dictates the attributes of the finished product for the consumer acceptability. Traditionally corn flakes are toasted in high efficiency forced convection systems such as rotary or fluidized‐bed ovens. The aim of the present work was to study microwave thin layer toasting of cooked flakes using a household oven. Flakes toasted in a fluidized‐bed industrial oven were adopted as control. The effect of microwave power level and process time on the kinetics of dehydration and quality parameters such as bulk density, thickness, and sensorial attributes of flakes were investigated. Kinetics data were satisfactorily simulated by Peleg's equation as function of drying time. A relationship between moisture ratio, output energy, and microwave power was also derived from experimental tests. A significant reduction of processing time in comparison with the traditional method was observed by selecting a suitable level of microwave power.