Abstract

The three primary floury and sweet maize types, with specialty kernels to make entire ready-to-eat maize, and packed in sealable paper envelopes, were the experimental units (150 g of raw kernels) to model the effect of the microwave heating-toasting (2450 MHz microwave oven, 492 W, times 0, 78, 156, 234, 312, and 390 s) on time -related variables and characterize the non-isothermal rheological properties. Pauses every 60 s for a rapid manual shaking compensated for non-uniformity of microwave volumetric heating. Surface color difference (Delta E*), inter-nal porosity, milling average particle size, and flour hydration properties displayed curves adequately described by simple and nonlinear regression models. The milling particle size, hydration properties, and rheological pa-rameters illustrated floury and sweet kernel differences ascribed to their proximal composition. Onset and peak temperatures depended on maize types and showed a little variation attributed to microwave heating-toasting times. The elastic/viscous modulus ratio increased in floury maize. It decreased in sweet maize, unveiling rheo-logical differences associated with microwave heating-toasting time effect on the contrasting structure of floury and sweet specialty Andean maize kernels used for toasting.