QUALITY ASSESSMENT OF REFINED OLIVE OILS BY GAS EXTRACTION

Olive oil is a vegetable oil that is extracted from olives by mechanic al means. Fractions of the oil thus produced have a high content of fr ee fatty acids and:require refining. Conventional refining processes m ay, however, alter the nutritional qualities of the oil. In recent yea rs, a study was carried out to evaluate the feasibility of deacidifyin g olive oil by supercritical carbon dioxide extraction. Extensive deac idification, resulting in low acid contents of the raffinates, was obt ained. Results obtained for other quality aspects of the supercritical fluid refined oil are reported here. Raffinates were analysed to dete rmine their overall ultraviolet absorbance, triglyceride profile by hi gh-performance liquid chromatography and stigmasta-3,5-diene content b y gas-liquid chromatography. The analyses made have shown that extract ion with supercritical fluid did not alter the nutritional quality of the processed virgin olive oil. (C) 1998 Elsevier Science B.V.