Engineering aspects of grain storage for quality maintenance.
Jayas, D. S.; Muir, W. E.; White, N. D. G.;
Proceedings of the International Wheat Quality Conference, Manhattan, Kansas, USA, 18-22 May 1997. Year: 1997 Pages: 397-412 Ref: 31 ref.
1997
บทคัดย่อ
A stored-grain bulk is a man-made immature ecosystem in which quality and nutritive changes of the grain occur because of interactions among physical, chemical and biological factors. The important factors are: temperature, moisture, carbon dioxide (CO2), oxygen (O2), grain characteristics, microorganisms, insects, mites, rodents, birds, climate, and granary structure. The definition of quality is dependent on the end use of the grain, for example, any loss in germination and germination capacity is detrimental for malting barley and subtle enzymatic changes during storage are detrimental to baking characteristics of wheat. The survival and reproduction of biological agents in grain are dependent to a great extent on the temperature and moisture levels. Localized regions may occur in bulk-stored grain for optimum development and multiplication of insects, mites, and fungi even when the average conditions of the bulk are not conductive to pest infestation. Engineers intervene by designing and eva
luating methods of modifying temperatures, moisture contents, and gas concentrations for preventing and controlling populations of insects, mites, and fungi in stored grain. Engineered operations, when performed properly during harvest and after harvest, should not have detrimental effects on the quality of grains, legumes, and oilseeds. Improper operations, however, can cause significant problems. Mechanical damage during harvest and postharvest handling may result in increased spoilage susceptibility by insects and moulds in storage and may promote autolytic enzymatic activity. High temperatures of drying air may reduce seed germination and increase stress cracks. High temperature driers may cause non-uniform drying of grain. Non-uniform distribution of drying air in low temperature driers may leave wet pockets that develop into hot spots.