Effets des chlorophylles, du bêtacarotène, de l’alphatocophérol, du tyrosol et de leurs interactions sur la stabilité oxydative de l’huile d’olive tunisienne

¹ Institut National Agronomique de Tunisie (INAT), 43, Avenue Charles Nicolle 1082 Tunis Mahrajène – Tunisie
² École Supérieure des Industries Alimentaires de Tunis (ESIAT), 58, Avenue Alain Savary 1003 El Khadra Tunis, Tunisie

^* ibentekaya@yahoo.fr

Reçu : 9 Décembre 2005
Accepté : 6 Décembre 2006

Abstract

Chlorophylls a and b, beta-carotene, alpha-tocopherol, tyrosol and their interactions effects on Tunisian extra virgin olive oil (EVOO) were studied. Beta-carotene, used at a level of 7 ppm, has an antioxidant effect more important at light than at obscurity. Chlorophyll a and b accelerate significantly the olive oil photooxidation, with a more important effect of chlorophyll b. When one or else of these chlorophylls is added with beta-carotene to oil, the global effect on peroxide value is attenuated. Both of alfa-tocopherol (0, 50, 100, 200, 400 ppm) and tyrosol (0, 5, 10, 20, 40 ppm) addition improved purified olive oil stability. On the other hand, alfa-tocopherol addition in EVOO has not significantly modified its oxidative stability, whereas that of tyrosol was very efficient. A factorial plane using three factors, beta-carotene (4 ppm), alfa-tocopherol (200 ppm) and tyrosol (50 ppm) is studied on EVOO and on purified olive oil. The results are different due to presence of various minor compounds on EVO.