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Role of minor compounds in the
oxydative stability of some virgin olive oils in Tunisia
Faten KOTTI*1,
Minyar KAHLOUN1, Kamel BEN AMMAR2, Mustapha
ISMAILI-ALAOUI3 and Mohamed GARGOURI1
1
Enzyme Engineering Group, Biocatalysis and Bioprocess Unit, National
Institute of Applied Science and Technology (INSAT), BP 676, 1080
Tunis Cedex, Tunisia.
faten.kotti@topnet.tn
Tel:
+216 71 703 829, Fax: +216 71 704 329.
2
Office National de l’Huile, Avenue Mohamed V,
Tunis,
Tunisia.
3
Institut Agronomique et Vétérinaire Hassan II,
Rabat,
Morocco.
Abstract
The main objective was to evaluate the phenolic and other compound
contents in virgin olive oils extracted from several varieties grown
in different locations in Tunisia. The phenolic content in the studied
olive oils varied from 54 to 550 mg kg-1. Contents in
α-tocopherol varied from 126.3 to 335.1 mg kg-1.
In the same way, the concentrations of some metal ions: iron, copper
and lead were measured in the oil samples to study their prooxidant
effects. Concentration of Fe in analysed oils reached 0,84 mg kg-1,
while concentrations of Cu and Pb did not exceed 0,11 and 0,055 mg kg-1.
By studying the oxidative stability of these oils, some positive
correlations between the phenols content and the induction time were
observed. Also the induction time seems to be increased by the oil
tocopherol richness. Nevertheless, no correlation could be established
between the oxidative stability and the metal ion concentration.
Keywords:
virgin olive oil, induction time, metal ions, phenolic compounds,
tocopherol.
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