Aeration trial of farm-stored wheat for the control of insect infestation and quality loss

Abstract

An aeration trial was conducted in collaboration with the Victorian Department of Agriculture, Australia, to study moisture content and quality changes in farm-stored wheat as a result of moisture uptake from the entering air. Two steel silos each filled with 44 tonnes of Olympic wheat at 33°C were aerated at the rate of 21/s per tonne with an average of 15 h of fan operation per week for 18 months. After 4 months of aeration, the average grain temperature at the centre of the bulk for each month ranged from 11–21°C depending on the season. The average moisture content of one bulk investigated in detail increased from 9.5 to 11.4% (w.b.) after 18 months of storage. Germination and some physical dough properties revealed some deterioration of the wheat near the duct. The rest of the bulk remained practically unaffected during storage and mainly free of storage fungi. Careful assessment of wheat quality before and after storage showed only small changes. The average insect fragment count at outloading was 6 100 g of flour which is considered to be a very low level. Germination and dough extensograph values were found to be, in this investigation, more sensitive indicators of deterioration than other quality tests.