Oli E.V. d'Oliva del Lazio: Studi di Caratterizzazione chimica-2

In the aim of put light on the role of geographic origin in the productive methodologies of virgin olive oils of Latium regio, where some DOPs have been assigned, were carried out some studies with the technical aid of the Chemical Laboratories of C.C.I.A.A. of Rome, the last of whom is reported here, whereas the first was conducted on the products of years 2004-5 with almost the same experimental design [1]. Ninety samples were analysed for acidity, peroxide number, sensory analysis, u.v. spectrum, fatty acids composition, together to tocopherols and polyphenols levels. Here we show the data relative to acidity, peroxide numbers and sensory analysis, according to the 2568/91/EC Rules, whereas tocopherols quantitation was according to a yet published method [1] and that of biophenols according to the NGD C 89-2007 method. The purpose was to put in evidence composition profiles and other features of the analysed oils able to make correlations with: e.g.,production origin or methodologies, keeping in mind, moreover, the nutritional relevance of the minor components. All samples resulted, based on the obtained values of free acidity and peroxides, well corresponding to the law requirements for an extra-virgin olive oil, with some exception for the sensory analyses data (12% of total samples). Total tocopherols were present between 98,60 mg/Kg and 291,8 mg/Kg, (mean±s.d.: 205,11 ± 39,1 mg/Kg, being alpha-tocopherol > 90%). Total biophenols were between 113 and 474 mg/Kg (mean ±s.d.:216 ± 55 mg/Kg), among them different secoiridoid structures and their derivatives, some flavonoids and phenolic acids were the main representative. All the analytical data were submitted to statistical analysis (one-way ANOVA).Some significant correlations were found: free acidity and peroxide values inversely related with total biophenols. Since biophenols and tocopherols could act as typicity markers for the different oils, the same were divided according the original geographical areas of production, that is: Sabina (44), Frosinone (13), Latina (11), Tuscia (9), Canino (8), Terre Tiburtine (4 samples). Statistically significant differencies (p < 0.05) were found between the biophenols or tocopherols levels, and the above areas. Hence a specific territorial variability of antioxidant micronutrient levels in the oils is clearly consequent, Other significant correlations between sensory profiles and cultivars. were found. Previous researches from our laboratories have regarded composition and stability of some cold pressed seed oils with high PUFA levels, mainly linoleic and alpha-linolenic acid. So, some linseed oils were analysed for tocopherols and biophenols, [2] finding generally much lower polyphenols levels than in olive oils and tocopherols profiles very different (gamma-tocopherol as main compound, but one was rich in the alpha-form). Other studies carried out on cold pressed sunflower, soybean, maize oils or others with regard to air and temperature stability gave very different result starting to the oil type. In a sunflower oil, we found unexpected amounts of t-PUFA by 13C nmr analysis [3] References [1] Bono S., et al., Atti del VI Congr. Naz. di Chimica degli Alimenti, Alba, 7/11/2006, 386-9. [2] Casini A., et al.: Atti del VII Congr. Naz. di Chimica degli Alimenti, Perugia, 23-6/6/2008 (ISBN 978-8886993-28-9); [3] A.Casini et al.: 1996, Riv.Sci.Alim. 25(4),329-47