Comment valoriser dans l'alimentation animale, les graines de soja produites en France ? Comparaison de deux proc de transformation : l'aplatissage-cuisson-pression et l'extrusion-pression

Abstract

How to develop the use for animal feeding, of soybean produced in France? Comparison of two processes: flaking-cooking-pressing and extrusion- pressing Cooking-pressing or extrusion-pressing processes applied to soybeans produce partially deoiled cake used for animal feeding. These two processes were studied and compared with a view to implementation in an industrial unit. The various factors of hydrothermal treatment for conditioning the beans were studied at different scales (batch from 2 kg to 100 kg, and continuous flow at 100 kg/h) and the results showed the need for moist cooking to effectively deactivate the antitrypsin factors (FAT) while maintaining protein solubility. The extrusion-pressing was more effective for deoiling cakes than cooking- pressing (5.4 vs. 6.7 %) but less robust for deactivation of FAT (6.5 vs. 3.8 TIU/mg). The techno-economical study was carried out to simulate the crushing costs and net margins of both processes in a plant capacity of 20 000 t / year. It showed that the costs of both methods were similar (about 33 s/t). Gross margins were evaluated between 18 and 84 s / t in three valuation assumptions based on market price of oil, the mode value of the meal and the residual oil, the level of premiums GMO traceability and transport. The cooking-pressing process can also be applied to sunflower and rapeseed and versatility is an advantage to ensure continuous operation of the crushing unit in case of supply difficulties in soybean.