Sterolic composition of Chétoui virgin olive oil: Influence of geographical origin.

The sterol profile of Tunisian virgin olive oils produced from Chétoui cultivar, the second main variety cultivated in the north of the country, grown under different environmental conditions, was established by gas chromatography using a flame ionisation detector. More than ten compounds were identified and characterised. As expected for virgin olive oil, the main sterols found in all Chétoui olive oils were β-sitosterol, Δ5-avenasterol, campesterol and stigmasterol. Cholesterol, 24-methylenecholesterol, clerosterol, campestanol, sitostanol, Δ7-stigmastenol, Δ5,24-stigmastadienol, and Δ7-avenasterol were also found in all samples, but in lower amounts. Most of these compounds are significantly affected by the geographical origin. The majority of the Chétoui virgin olive oils analysed respected EC Regulation No. 2568, and in all cases total sterol amounts were higher than the minimum limit set by legislation, ranging from 1017 to 1522mg/kg. Two triterpenic dialcohols (erythrodiol and uvaol), were also detected besides the sterolic components. Their content was below the upper legal limit of 4% in all analysed samples, with a range from 1.2% to 3.2%. These results suggest that, besides the genetic factor, environmental conditions influence the sterolic fraction.

[1]  M. T. Rodriguez-Estrada,et al.  Composition of total sterols (4-desmethyl-sterols) in extravirgin olive oils obtained with different extraction technologies and their influence on the oil oxidative stability , 2007 .

[2]  Y. Chen,et al.  beta-Sitosterol inhibits HT-29 human colon cancer cell growth and alters membrane lipids. , 1996, Anticancer research.

[3]  A. Pasqualone,et al.  Free and total sterols in olive oils. Effects of neutralization , 2000 .

[4]  Arturo Cert,et al.  Determinación de esteroles y dialcoholes triterpénicos en aceite de oliva mediante separación de la fracción por cromatografía líquida de alta eficacia y análisis por cromatografía de gases. Estandarización del método analítico. , 1997 .

[5]  G. Fregapane,et al.  Chemical composition of commercial cornicabra virgin olive oil from 1995/96 and 1996/97 crops , 1998 .

[6]  D. G. Lindsay,et al.  Plant sterols: biosynthesis, biological function and their importance to human nutrition. , 2000 .

[7]  E. Stefanoudaki,et al.  Effect of extraction system, stage of ripeness, and kneading temperature on the sterol composition of virgin olive oils , 1999 .

[8]  A. Awad,et al.  Peanuts as a Source of β-Sitosterol, a Sterol With Anticancer Properties , 2000 .

[9]  F. Gutiérrez,et al.  Relation of acidity and sensory quality with sterol content of olive oil from stored fruit. , 2000, Journal of agricultural and food chemistry.

[10]  V. Piironen,et al.  Phytosterol content in seven oat cultivars grown at three locations in Sweden , 1999 .

[11]  Beatriz P. P. Oliveira,et al.  Chemometric characterization of three varietal olive oils (Cvs. Cobrançosa, Madural and Verdeal Transmontana) extracted from olives with different maturation indices , 2007 .

[12]  Federico Marini,et al.  Chemical authentication of extra virgin olive oil varieties by supervised chemometric procedures. , 2002, Journal of agricultural and food chemistry.

[13]  Abderraouf El Antari,et al.  Estudio de la influencia de la variedad, los factores ambientales y las técnicas de cultivo en las características de los frutos y la composición química del aceite de oliva virgen extra de Marruecos , 2000 .

[14]  G. Fregapane,et al.  Sterol and alcohol composition of Cornicabra virgin olive oil: the campesterol content exceeds the upper limit of 4% established by EU regulations , 2004 .

[15]  E. Stefanoudaki,et al.  Effect of drought stress on qualitative characteristics of olive oil of cv Koroneiki , 2001 .

[16]  F. Gutiérrez,et al.  Effect of olive ripeness on the oxidative stability of virgin olive oil extracted from the varieties picual and hojiblanca and on the different components involved. , 1999, Journal of agricultural and food chemistry.

[17]  K. White,et al.  Validated method for quantitation and identification of 4,4-desmethylsterols and triterpene diols in plant oils by thin-layer chromatography-high resolution gas chromatography-mass spectrometry. , 1997, Journal of AOAC International.

[18]  A. Ranalli,et al.  Integral centrifuges for olive oil extraction. The qualitative characteristics of products , 1996 .

[19]  S Vichi,et al.  Detection of hazelnut oil in virgin olive oil by assessment of free sterols and triacylglycerols. , 2001, Journal of AOAC International.

[20]  H. Ajana,et al.  Fatty acids and sterols evolution during the ripening of olives from the Moroccan Picholine cultivar. , 1998 .

[21]  G. Fregapane,et al.  Influence of extraction system, production year and area on Cornicabra virgin olive oil: a study of five crop seasons , 2003 .

[22]  Joana S. Amaral,et al.  Classification of PDO olive oils on the basis of their sterol composition by multivariate analysis , 2005 .

[23]  Leila Abaza,et al.  Location effects on oxidative stability of Chétoui virgin olive oil , 2006 .

[24]  J. Cornforth.  Sterol biosynthesis: the early days. , 2002, Biochemical and biophysical research communications.

[25]  Emilio Osorio Bueno,et al.  Características sensoriales de aceites de oliva virgen procedentes de cultivares tunecinos monovarietales e híbridos con variedades europeas , 2007 .

[26]  B. Javornik,et al.  DNA Fingerprinting of Olive Varieties by Microsatellite Markers , 2002 .

[27]  Jacinto Sánchez Casas,et al.  Sterol and erythrodiol + uvaol content of virgin olive oils from cultivars of Extremadura (Spain) , 2004 .

[28]  R. Ostlund,et al.  Phytosterols in human nutrition. , 2003, Annual review of nutrition.

[29]  P. Cioni,et al.  Volatile compounds from Chétoui olive oil and variations induced by growing area , 2006 .

[30]  M. Gómez.  Composición química de distintas calidades de aceites de oliva virgen de la variedad "Empeltre" en el bajo Aragón , 2001 .

[31]  A. Alvarruiz,et al.  Evaluation of potential and real quality of virgin olive oil from the designation of origin “Aceite Campo de Montiel” (Ciudad Real, Spain) , 2007 .

[32]  A. Ranalli,et al.  Sterol and alcohol components of seed, pulp and whole olive fruit oils. Their use to characterise olive fruit variety by multivariates , 2002 .

[33]  Leila Abaza,et al.  Natural Antioxidant Composition as Correlated to Stability of Some Tunisian Virgin Olive Oils , 2005 .

[34]  A. Fernandez-Gutiérrez,et al.  Separation and determination of sterols in olive oil by HPLC-MS , 2007 .