-In this study we evaluate the chemical composition of sunflower oils obtained separately by pressing and subsequent solvent extraction from a new seeds rich in phytosterols (IASP-18) and conventional seeds . Results have shown that the total content of oil was much lower in the IASP-18 (18.1%) than in the conventional (37.5%) seeds. The extraction yield obtained by pressing was as low as 3% in the IASP-18 seeds and 37.5% in HA-89, while in the solvent extraction it was of the same order (∼18 wt% on seeds extracted by pressing) for the two types of seeds. No significant changes in the fatty acid composition were found between the oils extracted by the two procedures, but the pressed oils presented significantly lower acidity and larger content of the unsaponifiable fraction. Expressed as free sterols, the total sterols were 37-38% more concentrated in the oils extracted with solvent, reaching amounts of 13 700 and 6500 mg/kg in the IASP-18 and HA-89 oils, respectively. No substantial differences were found in the composition of total sterols analysed as free sterols between the oils extracted with the two procedures, but the contents of free sterols and sterol glycosides were much higher in the oils extracted with solvent.Keywords: Sunflower oil / pressing / solvent extraction / phytosterols Résumé -Caractérisation des huiles de tournesol obtenues séparément par pressage et extraction ultérieure par solvant à partir des nouvelles graines riches en phytostérols et des graines conventionnelles. Dans cette étude, nous évaluons la composition chimique des huiles de tournesol obtenues séparément par pressage et ultérieure extraction par solvant, à partir de nouvelles graines riches en phytostérols (IASP-18) et des graines conventionnelles (HA-89). Les résultats ont montré que la teneur totale en huile était beaucoup plus faible dans l'IASP-18 (18,1 %) que dans les des graines conventionnelles (37,5 %). Le rendement d'extraction obtenu par pressage était aussi bas que 3 % dans les graines de l'IASP-18 et de 37,5 % dans les HA-89, tandis que dans le solvant d'extraction, il était du même ordre (∼18 % en poids des graines extraites par pressage) pour la deux types de graines. Aucune modification significative de la composition en acides gras n'a été trouvée entre les huiles extraites par les deux procédures, mais les huiles pressées présentaient une acidité significativement inferieur et supérieure teneur de fraction insaponifiable. Exprimé en stérols libres, les stérols totaux étaient 37-38 % plus concentrés dans les huiles extraites avec solvant, atteignant, respectivement, les montants de 13 700 et 6500 mg/kg dans les huiles d'IASP-18 et de HA-89. Aucune différence substantielle n'a été trouvée dans la composition de stérols totaux analysés sous forme de stérols libres entre les huiles extraites avec les deux procédés, mais le contenu de stérols libres et les glucosides de stérols étaient beaucoup plus élevés dans les huiles extraites avec solvant.Mots clés : Huile de tournesol / pressage / extraction par so...

In this paper, the distribution of sterol compounds has been analyzed in 10 samples of new sunflower seeds with high contents of phytosterols. The sunflower seeds were first extracted with hexane and the residual oil was then extracted with a mixture of chloroform:methanol (2:1). In addition, the lipids from the defatted seeds and from the total seeds were analyzed after acid hydrolysis and subsequent extraction. The evaluation of the sterol compounds was performed by high temperature GC directly in the sylanized unsaponifiable matter using a-cholestanol as internal standard. This procedure allows for the quantification of free sterols and steryl glycosides in the oils extracted by hexane and chloroform:methanol (2:1) while in defatted meal and total seeds, they are determined as free sterols. The main characteristics of the fractions extracted by hexane were a variable oil content (19.8-38.7%) with medium unsaponifiable matter (1.4-4.8%), The major sterol compounds in the oil extracted by hexane were free sterols (4034-8507 mg/kg) while steryl glycosides were in low concentrations (80-280 mg/kg). On the contrary, the fraction extracted by chloroform:methanol had low lipid content (2.2-6.7%) with a high unsaponifiable matter (12.6-28.2%). The major sterol compounds in this fraction were steryl glycosides (9711-22 514 mg/kg). Finally, a third of the total sterols remained in the meal after the extraction of edible oil by hexane.