Heat Production of Stored Canola Seeds under Airtight and Non-Airtight Conditions

Abstract

Abstract. Heat production by 14.0% moisture content (MC) canola seeds was determined at 30°C and 20°C under airtight and non-airtight storage conditions by using a transient method. The 14.0% MC canola seeds were placed inside copper balls (15 cm diameter with 1.5 mm wall thickness). The balls were located at the center of cubic plywood boxes (50 cm long in each inner dimension) which were filled with 8.0% MC canola seeds. The plywood boxes were insulated with Styrofoam (14.5 cm thickness). Thermocouples were installed inside and outside the boxes and balls at 27 locations. The heat production rate was calculated by using finite element, analytical, and Fourier law methods. The heat production rate calculated by the finite element method was the heat production rate of the 14.0% MC canola, while the analytical and Fourier law methods overestimated and underestimated the heat production rate, respectively. The mean heat production rates at 30°C non-airtight, 30°C airtight, and 20°C non-airtight conditions were 0.102 ±0.001, 0.084 ±0.003, and 0.036 ±0.001 W kg -1 , respectively. Accumulated heat increased with increase of temperature and decrease of airtightness. The dry mass loss of canola seeds due to respiration of microflora was in accordance with heat production, moisture content increment under airtight condition, and microorganism infestation. The measured heat production ratios were higher than or equal to the theoretical value when only glucose was used as substrate for decomposition.