Nutritional quality of extra virgin olive oils from two different Olea Europea cultivars: application of a functional matematic index

P76 - NUTRITIONAL QUALITY OF EXTRA VIRGIN OLIVE OILS FROM TWO DIFFERENT OLEA EUROPEA CULTIVARS: APPLICATION OF A FUNCTIONAL MATEMATIC INDEX D.Di Majo1, E. Finotti2, M. La Guardia3, M. L. Picone4, S. Palumbo1, M. Giammanco1, S. Giuliano4 1 Unità Didattico Scientifica di Fisiologia e Farmacologia, Dip.DIGSPO, Università di Palermo; 2 CRA-NUT, Centro di Ricerca per gli Alimenti e la Nutrizione, Roma; 3 Dip. STEBICEF, Università di Palermo; 4 Agenzia delle Dogane, Laboratorio Chimico, Palermo Corresponding author: Danila Di Majo, Unità Didattico Scientifica di Fisiologia e Farmacologia, Dip. DIGSPO, e-mail. danila.dimajo@unipa.it, phone +390916236405 Background The extra virgin olive oil is very important in the Mediterranean diet. From the nutritional point of view, the high energy content and an optimal ratio between saturated and unsaturated fatty acids, together with the presence of minor compounds such as phenols and tocopherols and the related antioxidant capacity, confer to this product a high healthy value [1]. The extra-virgin oil’s nutritional properties depend on the pedoclimatic conditions, cultivar and the production process. In the last years many studies have been performed to remark and describe the safety and nutritional quality of the extra-virgin olive oils but it is difficult to compare different parameters representative of oil’s nutritional quality and to establish which of them is more important to define the nutritional value of an oil. In 2007, Finotti et al.[2] developed a Functional Mathematic Index (FMI) in order to quantify the nutritional quality of extra virgin olive oil and then the same authors applied it at other foods, such as tea [3], potatoes [4]. This index is important because it is able to convert a concept as the “quality” into a numeric quantity. The FMI takes into account different nutritional, antioxidant and chemical parameters representative of oil properties. These parameters, suitably processed with the “FMI Workbench” free software, provide a unique value indicated as “global” quality index (IGQ). We have calculated both the global FMI and the local FMIs. Aim of this study is to compare the nutritional properties of extra virgin olive oils from different olive varieties, Biancolilla and Oglialora grown in Sicily, by the functional mathematic index [5] Methods: samples of extra-virgin olive oils from two different cultivar (Biancolilla, Oglialora) and processed by different extraction methods (continuous cycle and hydraulic press) have been analyzed. The drupes are grown in the same climatic conditions. The parameters analyzed to calculate the FMI have been divided in three groups which are related to chemical, nutritional, technologic properties of oil. The three groups are: Nutritional parameters: fatty acids (numbers from 1 to 4, in table 1). Chemical parameters: acidity and peroxide number (numbers 5 and 6 in table 1); Technological process parameters: lipidic antioxidant capacity, tocopherols and total phenols (numbers 7-9 in table 1). The results of the analyses were processed by the software and the IGQ and LQ of each oil sample have been compared in order to define which of them had the better nutritional properties. The FMI varies from zero to one (good to poor). The global index has been expressed as “goodness percentage” (%FMI). The upper and the lower bounds for each group are established and they are report in the following table 1. Results: the analyses allow to classify all oil samples as extra-virgin olive oils. All parameters are within the limits of the Italian (E.U.) law and those established in table 1. No difference among two cultivars about acidity, peroxide number and fatty acids profile was found. The lipofilic antioxidant capacity was higher in Biancolilla variety than in Oglialora with both extractive methods (p=0,0001); sample oils extracted with continuous method have shown a lower of 16% content of tocopherols for both variety. Table 1: parameters and methods used to analyse of the extra-virgin oil samples. Upper and lower bounds for each parameters established according Finotti et al. [2] Index number Parameters Method used to analyze and related references Lower Bound Upper bound 1 Palmitic acid (C16:0) Chromatographic analyses (EU Regulation 2568/91, All. Xa and All. Xb) 7,5% 20% 2 Stearic acid (C18:0) 0,5% 5% 3 Oleic acid (C18:1) 55% 83% 4 Linoleic acid (C18:2) 3,5% 21% 5 Acidity EU Regulation 2568/91, all. II 0% 0,8% 6 Peroxide number EU Regulation 2568/91, all. III 0 meq/O2 20 mEq/O2 7 Lipidic antioxidant capacity (Finotti et al.1998,2000) -1,6 Ka/Kc + 1,6 Ka/Kc 8 Tocopherol HPLC, detector UV/Vis (method of SSOG) 1,2mg/100g 43mg/100g 9 Total phenols HPLC, detector UV/Vis (method of SSOG) 20 mg/Kg 900 mg/Kg The FMI of all oil samples varies from 0.27 to 0.34, therefore they satisfy the necessary conditions to be considered high quality extra-virgin oil; Nonetheless, the cultivar Biancolilla has shown a global index better than the Oglialora. From the study of local FMI we observed that the nutritional quality of oils extracted by continuous cycle is penalized in the total polyphenols and lipofilic antioxidant capacity parameters. Conclusion: the FMI allows to detect that the Biancolilla variety is better than Oglialora and then to underline which parameter can be modified in order to increase the nutritional quality of the oil analyzed. References: [1] Tripoli E., Giammanco M, Tabacchi G, Di Majo D., Giammanco S, La Guardia M. The phenolic compounds of olive oil: Structure, biological activity and beneficial effects on human health (Review).Nutrition Research Reviews,2005, 18:98-112; [2] Finotti E., Bersani A.M., Bersani E. Total quality indexes for extra-virgin olive oils. Journal of Food Quality, 2007,30:911-933; [3] Finotti E., Bersani E., Friedman M. Application of a Functional Mathematical Index for Antibacterial and Anticarcinogenic Effects of Tea Catechins. Journal Agricultural Food Chemistry, 2011,59: 864-869; [4] Finotti E, Bersani E., Del Prete E., Friedman M. A functional mathematical index for predicting effects of food processing on eight sweet potato (Ipomoea batatas) cultivars.Journal of Food Composition and Analysis,2012, 27: 81-86; [5] Finotti E, Bersani E, Bersani AM, Vivanti V, Toti E.,Variation of nutritional parameters in the olive oil during the ripening phase. La Rivista di Scienze dell’Alimentazione, 2011,2:33-41