Implementing the ‘dry chain’ during storage reduces losses and maintains quality of maize grain

Abstract

Maize grain quality is dependent on seed moisture content as high seed moisture leads to attack of stored grain by pests and to contamination by aflatoxin. Dry Chain is an economically viable and environmentally friendly option to overcome these problems. Dry Chain implies an initial drying of a commodity to low moisture and maintaining the low moisture throughout the supply chain. The quality of maize grain was experimentally evaluated after 4 months storage at 8, 10, 12 and 14% seed moisture content (SMC) in traditional packaging materials (paper, woven polypropylene, jute and cloth) and in hermetic bags (Super Bags) at Faisalabad, Pakistan. Results revealed significant changes in moisture content of grain stored in traditional packaging materials with varying environmental relative humidity, but moisture contents remained stable and low in the hermetically-sealed bags. Grain stored in Super Bags with 8% and 10% moisture content maintained high germination (93% and 88% after 2 and 4 months storage, respectively) and high starch and crude protein content. Higher concentrations of malondialdehyde (a measure of oxidative damage) and aflatoxins were observed in seeds stored at 14% SMC in both the sealed Super Bags and traditional packaging materials. The main benefit of the hermetically-sealed bags was reduction in incidence of the lesser grain borer (Rhyzopertha dominica). Damage and storage losses caused by the borer over a period of 4 months were 10% higher in conventional storage bags. In conclusion, insect populations and associated storage losses, and deterioration of maize seed quality with respect to loss of germination, food reserves and increased aflatoxin contamination can be controlled by maintaining the Dry Chain through hermetic storage of maize grain at 8% and 10% SMCs.