Determination of the Phenol and Tocopherol Content in Italian High-Quality Extra-Virgin Olive Oils by Using LC-MS and Multivariate Data Analysis

摘要

Italian extra-virgin olive oil market presents several kinds of products, some of which are of higher quality compared to others. Italian high-quality extra-virgin olive oils can have Protected Designation of Origin, Protected Geographical Identification and organic farming denominations. Each high-quality olive oil produced shows peculiar chemical composition and organoleptic characteristics. The present work was aimed to endorse the use of Italian high-quality extra-virgin olive oils and to promote the "Italian quality olive oil culture" to the consumers. To obtain this, task two analytical methods were developed in order to investigate the phenol and tocopherol contents in one hundred eighty-six high-quality extra-virgin olive oils by using HPLC coupled to mass spectrometry and fluorimetric detection, respectively. Olives milled to obtain these samples belong to forty-seven different cultivars. Furthermore, four different assays were used in order to evaluate antioxidant activity of all samples: TEAC, ORAC, FRAP, and DPPH, while the total phenols content was assessed by the Folin-Ciocalteu method. Finally, all these information were used to make a principal component analysis (PCA) in order to verify a possible correlation between oils belonging to the same region, or to the same cultivar, or to denomination. To the best of our knowledge, this is the first research article that reports the bioactive molecule content and a PCA statistical correlation between total phenol content, antioxidant activity (TEAC, FRAP, DPPH and ORAC), tocopherols and phenols in a large array of Italian high-quality extra-virgin olive oils (174) produced in different regions; in addition a number of 12 samples came from foreign countries (Portugal, Spain and Croatia). The gathered information attained could be useful for the generation of a database of a qualitative and quantitative profile of antioxidant molecules in extra-virgin olive.