Storage of canola in hermetic plastic bags

Abstract

Due to the small size of the seed, canola (Brassica napus or Brassica campestris) offers different challenges in the harvest and the subsequent post-harvest operations. Often, in Argentina, farmers do not have enough permanent storage capacity so they overcome this deficit with the use of hermetic plastic bags (silobags). The objectives of this work were: 1) Determine the feasibility of the bagging and extraction processes of canola. 2) Monitoring the condition of canola by periodic measurement of carbon dioxide (CO2), temperature, moisture content (m.c.) and quality of the grain. Thirty tonnes of canola with initial m.c. of 6 % were stored in a silobag in the southeast of the Buenos Aires province, Argentina. The storage period was extended from November 2008 to November 2009. The variables measured every two weeks were CO₂ concentration, m.c. and grain quality parameters, such as foreign matters, fat acidity and fat content. The temperature and relative humidity (r.h.) of the interstitial air inside the bag and of the ambient air were also recorded with a frequency of one hour. It was observed that, even the size and characteristics of the canola seeds, it was possible to perform the bagging and extraction operations of canola seeds without problems. The r.h. in the interstitial air remained below 50% along the entire storage period. The temperature of the grain inside the bag followed the monthly average ambient temperature. The CO₂ concentration ranged from 1 to 8 %, indicating low to moderate biological activity in the grain mass. The m.c., foreign matters and fat values remained unchanged throughout the storage period. The fat acidity increased during storage in 0.7 % points, reaching a final value of 1.4 %, but did not represent a commercial quality loss. It was concluded that under the conditions of temperature and m.c. evaluated in this study it is possible to store canola in hermetic plastic bags without commercial quality deterioration.

Keywords: Silobags, CO₂ concentration, Interstitial air, Moisture content, Fat acidity.