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Abstract

Free and esterified forms of sterols provide detailed information on the identity and the quality of vegetable oils. In this study, 4,4'-dimethylsterols in free and esterified forms were investigated in hazelnut and virgin olive oils. Moreover, a sample of solvent-extracted hazelnut oil was refined at the laboratory to monitor the effects of processing on the levels of 4,4'-dimethylsterols. Generally, the level of total 4,4'-dimethyslterols was higher in the esterified form (49-68%) compared with that in free form (32-51%) of these compounds in the hazelnut oil. In virgin olive oil samples, cycloartenol and 24-methylenecycloartanol were present in higher amounts in free forms (70-80%) than in esterified forms (20-30%). Among the refining processes, degumming, deodorization, neutralization and bleaching, only neutralization and bleaching considerably reduced 4,4'-dimethylsterols. In fully refined hazelnut oil, 18 and 37% of lupeol and an unknown compound X in the esterified form were lost, respectively. The loss of these two compounds in the free form was considerably higher, 26 and 72%, respectively. GC-MS analysis showed that adulteration of olive oil with a sample of fully refined hazelnut oil could be detected at a level as low as 2% by tracing lupeol in total or only in esterified forms of 4,4'-dimethylsterols. Further studies on the levels of free and esterified 4,4'-dimethylsterols and their retention during refining processes are anticipated in hazelnut cultivars from different origins

Keywords

adulteration; esterified 4; 4 '-dimethylsterols; free 4; 4 '-dimethylsterols; esterified sterols; free sterols; hazelnut oil; olive oil; triterpene alcohols; vegetable oil refining

Published in

Journal of the American Oil Chemists' Society
2007, volume: 84, number: 3, pages: 297-304
Publisher: SPRINGER

SLU Authors

UKÄ Subject classification

Food Science

Publication identifier

  • DOI: https://doi.org/10.1007/s11746-006-1025-1

Permanent link to this page (URI)

https://res.slu.se/id/publ/16408