Analysis of the physical quality of genetically modified and conventional maize grains in the drying and wetting processes

Abstract

The aim of this work was to evaluate the physical quality of the genetically modified corn grains (Herculex 30S31) as a function of drying and wetting processes in relation to conventional corn (AG 1051). The experimental design was a completely randomized design, with a factorial scheme (7x3x2), seven drying or wetting times (0, 20, 40, 60, 80, 100, 120 minutes), three drying air temperatures (80, 100 and 120 °C) and two types of maize (conventional AG 1051 and Herculex 30S31 transgenic). The grains of transgenic and conventional corn were harvested with a water content of 13.5% (w.b.) and dried in convection oven with forced ventilation, then the same grains were submitted to a wetting process for the same time. The width, thickness, length, contraction and expansion of the grains were determined, the water contents and the electrical conductivity were determined before and after drying, after the wetting process, at each interval of twenty minutes. Drying and wetting processes adversely affected the quality of conventional and transgenic maize grains. However, when compared, transgenic corn kernels were more resistant to physical damage. It was concluded that the changes in water contents in the grains during the drying and storage operations intensify the physical losses, even if at the end the grains remain with water content favorable to storage.