Lorenzo Cerretani a Alessandra Bendini a Annalisa Rotondi b Giovanni Lercker a Tullia Gallina Toschi a a Dipartimento di Scienze degli Alimenti, Università di Bologna, Cesena (FC), Italy b Istituto di Biometereologia, Consiglio Nazionale delle Ricerche (CNR), Bologna, Italy Analytical comparison of monovarietal virgin olive oils obtained by both a continuous industrial plant and a low-scale mill In this paper, two monovarietal extravirgin olive oils, obtained from Ghiacciolo and Nostrana di Brisighella cvv. olives, were produced by two different extraction plants, a low-scale mill equipped with a two-phase decanter and a continuous water-saving industrial plant. The olive ripening index, the fatty acid analysis by capillary gas chro- matography, the spectrophotometric determinations of total phenols and o-diphenols, the phenolic profile by HPLC-DAD/MSD and the oxidative stability by OSI, together with the sensory analysis on the oil produced, were evaluated. Independently of the olive processing plant, the oils originating from two cultivars of olive fruit showed dif- ferent fatty acid compositions (particularly the C18:1/C18:2 ratio), phenol composi- tions and oxidative stabilities. Concerning the extraction system, for both cultivars, the oxidative resistance and the content of phenols and o-diphenols were higher for the oils produced by the low-scale mill. The quantitative descriptive analysis sensory analysis was not able to discriminate the oil samples from both cultivars obtained from the two plants, even if it underlined a higher bitter attribute for the Ghiacciolo cv. oil when it was obtained from the low-scale mill. The data of the sensory analysis were correlated with simple phenol and the secoiridoid contents, both determined by HPLC- DAD-MSD. Keywords: Phenols, HPLC-MSD, extravirgin olive oil, sensory analysis, low-scale mill. 1 Introduction Unlike other vegetable oils, the extravirgin olive oil made from olive fruits (Olea europaea L.) is only obtained from mechanical phases (crushing, malaxation and cen- trifugation) and is then consumed without refinement. The technological procedures employed in this process keep the oil’s original characteristics almost unmodified, and this fact is the most important in regard to the nutritional [1] and sensory [2] properties and the resistance to oxi- dative degradation [3, 4]. It is well known that the quality of extravirgin olive oil is related to agronomic [4–7], technological [6–9] and stor- age factors [10, 11]. In the last century, the extraction process has been changing, due to the fact that it is adjusted to the new industrial reality in the different pro- ducer countries. Nowadays, in Spain there are especially two-phase continuous industrial systems which have a work capacity of around 2500–3000tons of olives per year. In Italy, the technological status is different; in fact there are both three-phase continuous systems and tradi- tional plants which have a work capacity of approximately 400–500tons of olives per year only. Moreover, in small Italian farms, the low-scale mill plant is recently spreading, especially for typical productions such as pitted and monovarietal olive oils. This work aims to compare two extravirgin monovarietal oils (cvv. Nostrana di Brisighella and Ghiacciolo), produced by both an industrial plant and a low-scale mill, in terms of sensory and qualitative char- acteristics. In order to evaluate these differences, the sensory quantitative descriptive analysis (QDA) was car- ried out, as well as a sensorial discriminant test; moreover, some chemical parameters (free acidity, peroxide value, K 232 ,K 270 and DK) were also determined. The quali-quan- titative phenolic profile was acquired, together with the evaluation of the oxidative stability of oil samples. 2 Materials and methods 2.1 Samples, standards, and solvents The present study was carried out on monovarietal extra- virgin olive oils (cvv. Nostrana di Brisighella and Ghiacciolo). The olive fruits came from an orchard located in the Emilia- Romagna region. Ten adult 50-year-old olive trees of cv. Correspondence: Lorenzo Cerretani, Dipartimento di Scienze degli Alimenti, Università di Bologna, P.zza Goidanich 60, 47023 Cesena (FC), Italy. Phone: 139 0547 338121, Fax: 139 0547 382348, e-mail: lorenzo.cerretani2@unibo.it Eur. J. Lipid Sci. Technol. 107 (2005) 93–100 DOI 10.1002/ejlt.200401027 93  2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim www.ejlst.de Research Paper