Gas chromatographic-mass spectrometric characterisation of triterpene alcohols and monomethylsterols in developing Olea europaea L. fruits

Abstract

Five triterpene alcohols and four 4-monomethylsterols were identified by GC-MS during the ripening of Picholine olive. The quantitative characterisation of these compounds was performed using GC-FID. The results showed that the maximum level of total triterpene alcohols (263.68 mg/100 g oil) was reached at 26th week after the flowering date (WAF) of olive; whilst the highest level of total 4-monomethylsterols (234 mg/100 g oil) was attained at 24th WAF of fruit. The percentage of these two classes represented 20-33% of total phytosterols during olive maturity. 24-Methylene cycloartenol (12-207 mg/100 g oil) and cycloartenol (27-198 mg/100 g oil) were the predominant triterpene alcohols during the ripening of Picholine olive; whereas citrostadienol (30-161 mg/100 g oil) and cycloeucalenol (11-74 mg/100 g oil) were the main 4-monomethylsterol compounds followed by obtusifoliol and gramisterol. β-Amyrin, δ-amyrin and traroxerol were less present in Picholine olive and they accounted for 14% of total triterpene alcohols at complete maturity of fruit. The level of these methylsterols was overwhelmed by the amount of 4-desmethylsterols at each stage of Picholine olive maturity. © 2009 Elsevier Ltd. All rights reserved.