Physico-chemical change and heat stability of extra virgin olive oils flavoured by selected Tunisian aromatic plants

• Published in: Food and chemical toxicology Vol. 47; no. 10; pp. 2613 - 2619
• Main Authors: Ayadi, M.A., Grati-Kamoun, N., Attia, H.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01-10-2009; Elsevier
• Subjects: Antioxidants - analysis; Aromatic plants; basil; Biological and medical sciences; Chemical Phenomena; essential oils; Flavoring Agents - chemistry; flavorings; free fatty acids; herbs; Hot Temperature; Lamiaceae - chemistry; Lavandula; lemons; Medical sciences; Ocimum basilicum; Oils, Volatile - chemistry; Olea; Olive Oil; Oxidation-Reduction; oxidative stability; peroxide value; Physico-chemical change; physicochemical properties; plant extracts; Plant Oils - analysis; Plant Oils - chemistry; Plant poisons toxicology; rosemary; Rosmarinus; sage; spices; Thermal oxidative stability; thermal stability; thyme; Thymus; Toxicology; Tunisia; Africa; Thermal oxidative stability; Olive oil; Aromatic plants; Physico-chemical change; Temperature; Heat; Plant; Plant origin; Environmental factor; Physicochemical properties; Thermal stability; Virgin oil
• ISSN: 0278-6915; 1873-6351
• DOI: 10.1016/j.fct.2009.07.024

Objectives of this work were studying physico-chemical change and heat stability of olive oils flavoured by selected Tunisian aromatic plants. Flavoured olive oils were prepared by maceration of fresh plant materials (rosemary, lavender, sage, menthe, basil, lemon and thyme) with olive oil at a 5% w/w level for 15
days. A sensorial evaluation was applied to select more appreciate flavoured olive oils by consumers. An oxidative procedure was applied to test the stability of selected flavoured olive oils: oils samples were kept in glass bottles and heated at 60 and 130
°C during 55
days and 6
h, respectively. The resistance to oxidation of these selected flavoured oils was compared to a control samples by measuring PV, K232 and K270 values and change in chlorophyll, carotenes and polyphénols contents. Obtained results show that addition of aromatic plants causes a slight increase in free acidity and viscosity of aromatised olive oils.
L*,
b* and
a* values show that addition of thyme cause a great change in olive oil colours. Heat stability results shows that from selected aromatic plants, rosemary was effectiveness against oxidation followed by thyme and lemon. However, olive oil flavoured with basil exhibit a similar behaviour versus thermal oxidation then the natural olive oil.