E XPERIMENT 2: C AN ALL THE S ARDINIAN VARIETIES SUPPORT THE PDO “S ARDEGNA ” VIRGIN OLIVE OIL ?

Pierfrancesco Deiana1,4, Mario Santona1, Sandro Dettori1, Maria Giovanna Molinu2, Antonio Dore2, Nicola Culeddu3, Emanuela Azara3, Maria Z. Tsimidou4

1_{Dipartimento di Agraria, Università di Sassari, Sassari} 2_{Istituto di Scienze delle Produzioni Alimentari, CNR, Sassari} 3_{Istituto di Chimica Biomolecolare, CNR, Sassari}

4_{Laboratory of Food Chemistry and Technology, Department of Chemistry, Aristotle} University of Thessaloniki, Thessaloniki (Greece)

ABSTRACT

Protected Designation of Origin (PDO) labels are important tools to promote high quality virgin olive oils (VOO). To better valorize and differentiate among others these labeled products is necessary a deep knowledge of characteristics and features of monovarietal VOO admitted to characterize them. In Sardinia, only one PDO, named “Sardegna”, is present. It covers the whole regional territory and several local varieties are admitted to its characterization, making difficult to define precisely the product. The aim of the study was to examine in depth chemical and nutritional characteristics of some monovarietal VOO included in the PDO Sardegna, with the purpose of identify the varieties and specific characteristics that might contribute to improve the quality of the label. PDO Sardegna VOO were compared with some minor Sardinia cultivars, Italian and Greek varieties, all grown with the same agronomic and environmental conditions. Fatty acid, phenolic and sterol composition from thirty-five VOO representative samples were determined. Moreover, α- tocopherol, squalene and apparent chlorophylls contents were determined. Results confirmed the high potential quality and variability of VOO produced by varieties affering to PDO Sardenga, proving to be good sources of bioactive molecules such as squalene, α-tocopherol and phenolic compounds. Some similarities and synonymies were observed whithin local varieties in accordance to genetic similarities. Moreover, genetic groups highlighted some distinctive features that might be useful for a further characterization of the label.

INTRODUCTION

Protected Designation of Origin (PDO) and Protected Geographical Indication (PGI) are quality and geographic labels introduced by European Union (EU) to promote and protect the quality names of food and wine products. They are connected to a territory as well as to support food safety and quality through the development of sustainable agriculture (Reg. EC No 2081/92, 1151/2012). According to the Database Of Origin and Registration (DOOR) concerning the olive oil sector, over the past 20 years EU has registered 124 extra virgin olive oil (EVOO) denominations (109 PDO and 15 PGI). Italy is the country with the highest number of denominations, 42 PDO and 4 PGI, followed by Greece (19 PDO and 11 PGI) and Spain with 30 PDO. The Italian EVOO quality labels usually are referred to a limited territory and a selected number of varieties, reflecting the peculiar characteristic of Italian olive growing: most of the 800 autochthonous documented cultivars are well adapted to a specific microclimatic area and are cultivated only in their area of origin (Muzzalupo, 2012). During the last period the Italian strategy regarding designation of origin turned towards PGI labels referring to a larger territory: Regions (e.g. PGI “Sicilia”, “Olio di Calabria” and “Marche”) (DOOR), names able to attract a larger number of potential consumers.

Similar policy probably guided in 2003 the drawing of the application for registration for the only virgin olive oil PDO, named “Sardegna”, subsequently registered in Sardinia in 2007. Nowadays this label holds a small percentage of the regional olive oil market, less than 3% (ISM A, 2016). PDO “Sardegna” can be produced along the whole territory and must be characterized at least for the 80% by the four principal autochthonous Sardinian varieties: Bosana, Tonda di Cagliari, Tonda di Villacidro, Semidana and respective synonymies. The remaining 20% may include virgin olive oils obtained from other varieties grown in the island. Growing areas are concentrated in five main zones: Sassarese and Alghero, Oristanese and Montiferru, Nuorese and Ogliastra, Medio Campidano and Marmilla, Parteolla and Trexenta (Bandino and Dettori, 2001). The Sardinian olive germplasm is rich and strongly linked to the traditions of the territory. Bandino et al (2001), utilizing morphological and structural parameters, described 28 autochthonous varieties. The principal are mainly diffused in the respective areas of origin and rarely cultivated out of such areas. The most widespread Sardinian cultivar is Bosana, including about the 65% of the cultivated trees (Bandino et al, 2011). Minor varieties (e.g. Pizz’e Carroga, Pezz’e Guaddu, Cariasina, Corsicana da Olio and

Sivigliana da Olio) are usually present as scattered trees inside secular olive orchards. Several studies have been carried out on Sardinian varieties regarding genetic relationships between Mediterranean germplasm and wild forms (Baldoni et al, 2006, 2009) and within Sardinian germplasm and between Sardinian and Italian varieties (Erre et al, 2010). Chemical composition and sensorial profile of some Sardinian virgin olive oil (VOO) have been widely studied under several aspects (Vacca et al, 2001; Angerosa and Basti, 2003; Giansante et al, 2003; Gallina-Toschi et al, 2005; Cerretani et al, 2006; Filigheddu et al, 2012; Bandino et al, 2011, 2012; Campus et al, 2013; Beltran et al, 2015; Tuberoso et al, 2016). Some authors investigated the effect of storage and extraction technology on the Sardinian VOO’s quality (Del Caro et al, 2006, 2012; Vacca et al, 2006; Fadda et al, 2012). Moreover, Sardinian VOOs have been involved in chemometric studies aimed to discriminate cultivars and geographical origin (Giansante et al, 2003; Bianchi et al, 2001; Culeddu et al, 2017). The role of microorganisms in Sardinian oleic ecosystems, and in particular the potential effect of the enzymatic activity of bacteria and yeasts on the sensory and physico-chemical properties of oil, has been recently described (Santona et al, 2018).

The size of the territory and the high number of possible varietal blends of PDO “Sardegna” strongly influence chemical composition and sensorial profile of VOO, and makes it difficult to define with precision this label. A first step towards a deeper label characterization is a detailed study of the monovarietal VOO of all the varieties included in the label, particularly the ones considered synonyms, which have been investigated only under some agronomical aspects (Bandino et al, 1999).

The aim of this work is to describe the principal chemical and nutritional properties of the monovarietal VOO included in the PDO “Sardegna”, compared with some minor Sardinian cultivars, Italian and Greek varieties grown with the same agronomical conditions. Moreover, the quality evaluation of monovarietal Sardinian oils compared to national and international cultivars could be a useful tool to increase the label value with higher quality olive oils. Moreover, knowledge of this monovarietal VOO could provide good guidelines to producers in the case of the formulation of new blends.