Concentration of CO2 in Hermetic and Non-Hermetic Storage and Effect on Incidence of Insect, Fungi, and Oil Quality of Corn Grain With Different Moisture Contents

Abstract

This study aimed to evaluate the dynamics of CO₂, temperature, and relative humidity in stored corn grains, as well as the quality of the grains and oil extracted over time. BRS284 corn grains were harvested and stored at moisture contents of 18, 16, and 14% wb, in both hermetic (GrainPro SuperGrainBag) and non-hermetic (experimental silos) storage conditions. Quality was assessed at 0, 30, 60, 90, and 120 days using a 2 × 3 × 5 factorial layout with three replications, which correspond to storage conditions, initial moisture content, and storage time, respectively. [CO₂], temperature, relative humidity, water activity, equilibrium moisture content, incidence of fungi and insect damage loss, ether extract content, acidity, peroxide and iodine indices, and fatty acid profiles were measured. Results showed that temperature, relative humidity, and [CO₂] increased with higher initial moisture content, with non-hermetic storage showing higher temperature (mean of 29.33°C ± 2.96°C) and relative humidity (mean of 89.99 ± 1.39), while hermetic storage exhibited higher [CO₂] with 320 × 10³ and 9435.34 ppm as maximum value for hermetic and non-hermetic storage, respectively. Grain quality and oil extraction were negatively affected by higher initial moisture contents (18 and 16% wb), particularly in non-hermetic storage (3.68 and 4.61 g 100 g⁻¹ dm of ether extract content), with more significant deterioration by 60 days. The fatty acid profile showed minor changes, with corn oil stability prevailing, and unsaturated-to-saturated fatty acid ratios ranging from 5.67 to 6.17.