Relationships between Oxidative Stability, Triacylglycerol Composition, and Antioxidant Content in Olive Oil Matrices
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- 作者：Raquel Mateos ; Mariana Trujillo ; M. Carmen Pé ; rez-Camino ; Wenceslao Moreda ; and Arturo Cert
- 刊名：Journal of Agricultural and Food Chemistry
- 出版年：2005
- 出版时间：July 13, 2005
- 年：2005
- 卷：53
- 期：14
- 页码：5766 - 5771
- 全文大小：101K
- 年卷期：v.53,no.14(July 13, 2005)
- ISSN：1520-5118
文摘
In olive oils, relationships between oxidative stability, glyceridic composition, and antioxidant contentwere investigated. Lipid matrices, obtained by purification of olive and high-oleic sunflower oils, werespiked with hydroxytyrosol, 
-tocopherol, and mixtures of them and then subjected to oxidation in aRancimat apparatus at 100 
C. At the same concentration of antioxidants, induction time (IT) decreasedas the unsaturation rate of the matrix increased, but only fair correlations were found with fatty acidcomposition. Oxidative susceptibility (OSTAG) was calculated as a function of the relative oxidationrate of the triacylglycerols, and a linear relationship-IT (h) = (a + b)OSTAG-between induction timeand this parameter showed a good correlation coefficient (r > 0.990, p < 0.001). In the case ofmatrices with a single antioxidant, origin ordinate (a) and slope (b) can be calculated as a functionof the antioxidant concentration. In matrices spiked with mixtures of hydroxytyrosol and -tocopherol,a simple relationship between the coefficients a and b and the concentration of antioxidants cannotbe established because additive and subtractive effects occur depending on the relative concentrationsof both antioxidants. However, approximate values for these coefficients can be obtained, allowingthe estimation of the oil stability. In various olive oils, an acceptable agreement was found betweenthe IT experimentally determined and that calculated from the oil composition. These results confirmedthat the Rancimat stability of olive oils mainly depends on triacylglycerol composition and concentrations of o-diphenols and -tocopherol.Keywords: Hydroxytyrosol; -tocopherol; antioxidant activity; Rancimat stability; olive oil; triacylglycerol composition
-tocopherol, and mixtures of them and then subjected to oxidation in aRancimat apparatus at 100 C. At the same concentration of antioxidants, induction time (IT) decreasedas the unsaturation rate of the matrix increased, but only fair correlations were found with fatty acidcomposition. Oxidative susceptibility (OSTAG) was calculated as a function of the relative oxidationrate of the triacylglycerols, and a linear relationship-IT (h) = (a + b)OSTAG-between induction timeand this parameter showed a good correlation coefficient (r > 0.990, p < 0.001). In the case ofmatrices with a single antioxidant, origin ordinate (a) and slope (b) can be calculated as a functionof the antioxidant concentration. In matrices spiked with mixtures of hydroxytyrosol and -tocopherol,a simple relationship between the coefficients a and b and the concentration of antioxidants cannotbe established because additive and subtractive effects occur depending on the relative concentrationsof both antioxidants. However, approximate values for these coefficients can be obtained, allowingthe estimation of the oil stability. In various olive oils, an acceptable agreement was found betweenthe IT experimentally determined and that calculated from the oil composition. These results confirmedthat the Rancimat stability of olive oils mainly depends on triacylglycerol composition and concentrations of o-diphenols and -tocopherol.Keywords: Hydroxytyrosol; -tocopherol; antioxidant activity; Rancimat stability; olive oil; triacylglycerol composition