title: Combined effect of carnosol, rosmarinic acid and thymol on the oxidative stability of soybean oil using a simplex centroid mixture design.
abstract: BACKGROUND
  Oxidation taking place during the use of oil leads to the deterioration of both nutritional and sensorial qualities. Natural antioxidants from herbs and plants are rich in phenolic compounds and could therefore be more efficient than synthetic ones in preventing lipid oxidation reactions. This study was aimed at the valorization of Tunisian aromatic plants and their active compounds as new sources of natural antioxidant preventing oil oxidation.
  
  
  RESULTS
  Carnosol, rosmarinic acid and thymol were isolated from Rosmarinus officinalis and Thymus capitatus by column chromatography and were analyzed by nuclear magnetic resonance. Their antioxidant activities were measured by DPPH, ABTS and FRAP assays. These active compounds were added to soybean oil in different proportions using a simplex-centroid mixture design. Antioxidant activity and oxidative stability of oils were determined before and after 20 days of accelerated oxidation at 60 °C.
  
  
  CONCLUSIONS
  Results showed that bioactive compounds are effective in maintaining oxidative stability of soybean oil. However, the binary interaction of rosmarinic acid and thymol caused a reduction in antioxidant activity and oxidative stability of soybean oil. Optimum conditions for maximum antioxidant activity and oxidative stability were found to be an equal ternary mixture of carnosol, rosmarinic acid and thymol. © 2016 Society of Chemical Industry.
authors.affiliation: Laboratoire d'Ecologie et de Technologie Microbiennes, Institut National des Sciences Appliquées et de Technologie, INSAT, University of Carthage, 1080, Tunis, Tunisia.
authors.forename: Salma
authors.initials: S
authors.lastname: Saoudi
authors.affiliation: Laboratoire d'Ecologie et de Technologie Microbiennes, Institut National des Sciences Appliquées et de Technologie, INSAT, University of Carthage, 1080, Tunis, Tunisia.
authors.forename: Nadia
authors.initials: N
authors.lastname: Chammem
authors.affiliation: Laboratoire Matériaux-Molécules et Applications, IPEST, University of Carthage, 2070, La Marsa, Tunisia.
authors.forename: Ines
authors.initials: I
authors.lastname: Sifaoui
authors.affiliation: Instituto Universitario de Bio-Orgánica Antonio González, Universidad de La Laguna, Tenerife, Canary Islands, Spain.
authors.forename: Ignacio A
authors.initials: IA
authors.lastname: Jiménez
authors.affiliation: University Institute of Tropical Diseases and Public Health, University of La Laguna, 38271, La Laguna, Tenerife, Canary Islands, Spain.
authors.forename: Jacob
authors.initials: J
authors.lastname: Lorenzo-Morales
authors.affiliation: Etablissements Slama Frères, Nejma Huiles, Oued Ellil-Manouba, Tunisia.
authors.forename: José E
authors.initials: JE
authors.lastname: Piñero
authors.affiliation: Etablissements Slama Frères, Nejma Huiles, Oued Ellil-Manouba, Tunisia.
authors.forename: Maha
authors.initials: M
authors.lastname: Bouassida-Beji
authors.affiliation: Laboratoire d'Ecologie et de Technologie Microbiennes, Institut National des Sciences Appliquées et de Technologie, INSAT, University of Carthage, 1080, Tunis, Tunisia.
authors.forename: Moktar
authors.initials: M
authors.lastname: Hamdi
authors.affiliation: Instituto Universitario de Bio-Orgánica Antonio González, Universidad de La Laguna, Tenerife, Canary Islands, Spain.
authors.forename: Isabel
authors.initials: I
authors.lastname: L Bazzocchi
mesh_terms: D045784:Abietanes / Q000032:analysis*; D002934:Cinnamates / Q000032:analysis*; D053630:Depsides / Q000032:analysis*; D005503:Food Additives / Q000032:analysis*; D005519:Food Preservation / Q000295:instrumentation / Q000379:methods*; D010084:Oxidation-Reduction; D013024:Soybean Oil / Q000737:chemistry*; D013943:Thymol / Q000032:analysis*; D000097123:Rosmarinic Acid
chemical_list: D045784:Abietanes; D002934:Cinnamates; D053630:Depsides; D005503:Food Additives; D013024:Soybean Oil; D013943:Thymol; D000097123:Rosmarinic Acid; C068623:carnosol
keywords: carnosol; mixture design; oxidative stability; rosmarinic acid; soybean oil; thymol