Micro-pressing of rapeseed (Brassica napus L.) and Arabidopsis thaliana seeds for evaluation of the oil extractability
Résumé
Pressing is a crucial step in the crushing process of rapeseed seeds, regarding its major effect on the oil extraction yield, the energy consumption and the quality of the meal. In order to study and model in a rigorous way the behaviour of rapeseed seeds, and the oil extraction during pressing, the potential of a micro-pressing technique using a instrumented micro press adapted to quantities of seeds as low as 10 g for rapeseed and 3 g for Arabidopsis thaliana was examined and discussed. Using a phenomenological model, data from the pressing process and the material behaviour (compressibility modules) were obtained with a good precision, highlighting small differences between samples. The well-known positive effect of the temperature on the oil extraction yield was confirmed with A. thaliana. Micro-pressing of ground and cooked rapeseed seeds did not lead to the results usually reported in the literature for continuous pressing. The results strongly suggest that the performance of the static micro-pressing is related to the macro-and micro-structure of seeds and is less sensitive to the moisture than continuous pressing. Further experiments are needed to confirm that the micro-pressing could be an effective tool for predicting the extractability of oil and therefore, contribute to plant breeding programmes in the future.