Thin layer drying rate and loss of viability modelling for rapeseed (Canola)

For the drying process and safe storage of rapeseed, the experimental equilibrium moisture content and the thin layer drying curves for rapeseed (Brassica napus L.), variety Hyola-401, were determined; and the effect of drying air temperature and relative humidity on seed quality was evaluated. The equilibrium moisture content curves were obtained, both experimentally and by fitting the modified Henderson equation to the experimental data, using non-linear regression. The same procedure was used to fit the Page thin layer drying equation to the thin layer drying experimental data. The results showed that both, the modified Henderson and the Page equations describe adequately the variation of equilibrium moisture content and thin layer drying rates, respectively, as a function of drying air temperature and relative humidity. It was also observed that the drying air temperature and relative humidity affect significantly the vigour and germination of rapeseed, showing that the drying conditions is a crucial factor for maintaining the physiological quality of the seeds. (C) 1999 Silsoe Research Institute.