Deciphering the structural organization of the oil bodies in the Brassica napus seed as a mean to improve the oil extraction yield
Résumé
A population of 95 winter oilseed rape accessions displaying contrasted lipid and protein contents has been used to find relations between the oil extraction efficienty and the structural organization of seed oil bodies (OBs). Evaluation of the crushing ability using the micro-pressing technique, revealed a high positive correlation between compressibility index and oil extraction yield. OBs hydrodynamic diameter decreased with the increases of temperature or pH and was negatively correlated to content in oleosins, the main structural OB proteins. OB stability was significantly affected by (i) genotype, the accessions with the lowest oil extraction levels displaying the most stable oil bodies, (ii) lowering the pH leading to OBs aggregation at pH lower than 7 and, (iii) the addition of divalent cations able to neutralize the negative charges on the OB surface. As far as genotypes characterized by the lowest oil extractability levels presented the most stable OBs, a link between seed extractability and OB stability could be suggested. Temperature, pH medium, and salt presence appearing to affect OB microstructure and suspension stability, could also be considered towards improvement of oil extraction efficiency. (C) 2012 Elsevier B.V. All rights reserved.