Effect of Roasting Corn at Different Temperatures on Grain Characteristics and In Vitro Starch Digestibility

Abstract

The effect of roasting corn to 107, 135, and 163 C on grain characteristics and in vitro starch digestibility was studied. Changes in grain characteristics of roasted corn varied with the exit temperature of the corn (dry matter loss, heat required, water absorption increased; moisture content and density decreased). Furthermore, these changes tended to correspond with in vitro starch digestion by amylase enzyme without preliminary heating. Heating during the starch digestion moderated differences by different roasting temperatures. The highest roasting temperature resulted in the greatest in vitro starch digestion. Any of the grain characteristics except gelatinization and particle size served as an indicator of digestibility of the roasted product. No birefringence was lost due to any of the roasting temperatures suggesting that more than dry heat was necessary to produce gelatinization. © 1975, American Dairy Science Association. All rights reserved.