## 1 Introduction  
Virgin olive oil (VOO) exhibits nutritional and sensory characteristics that make it valuable component of Mediterranean diet. It is produced in large quantities from different varieties of _Olea europaea_ L. fruits using physical methods. VOO shows sensory characteristics and nutritional properties that distinguish it from the other oil types. VOOs obtained from fresh and undamaged (neither mechanically nor by insects and moulds) olive fruits, after proper processing, are characterized by a delicate and unique flavour highly appreciated by consumers. Their peculiar attractive taste and aroma is related to several non-volatile compounds and to a number of volatile organic compounds (VOCs) [1]. Most of the VOCs are formed during the mechanical extraction process through the action of enzymes that are released when the fruits are crushed, and continue to form during malaxation in the enzymatic reactions known as lipoxygenase pathway [2]. The VOCs of virgin olive oil depends on several factors, such as the level and activity of the enzymes involved in various pathways [3; 4], the cultivar [5; 6], the ripening cycle of the fruit [7], the processing equipment [8], the extraction method and storage conditions [9], the climate and soil type [10] and the growing area [11]. VOOs have been particularly appreciated due to high stability with respect to other vegetable oils, which may be caused by the presence of phenolic compounds and tocopherols.  
Due to the high content of beneficial constituents, such as monounsaturated fatty acids (MUFAs) and phenolic compounds, olive oil consumption has been steadily increasing all over the world and drives olive cultivation in new areas such as Latin America, California, South Africa, China, and Australia [12]. According to some authors, the beneficial impact of olive oil on health is mainly attributed to its richness in monounsaturated and low unsaturated fatty acids as well as to polyphenols (which act as natural antioxidants) that may together contribute to the prevention of several human diseases such as coronary heart disease, cognitive impairment, colon cancer and many others [13]. The nutritional value of VOO arises not only from high levels of oleic acid and the presence of hydrophilic phenols but also from minor components such as phytosterols, carotenoids and tocopherols [14]. The minor components present in the olive oil were the subject of many studies [15; 16]. Phenol types and concentrations differ greatly, since many factors such as cultivars [17], ripening degree, seasonal variation, climate and area of origin [10] affect phenolic content in the olive oil. VOOs can be also considered as an example of a functional food containing a variety of components that may contribute to their overall therapeutic characteristics.  
Lately, special attention has been focused on researching monovarietal oils and the oils containing various forms of protection (e.g., geographical, ecological, _etc._), which significantly contributes to the popularization of olive oil and strengthening of the economy through the olive sector. In this study, the large spectrum of quality parameters of VOOs obtained from Croatian autochthonous varieties _Masnjaca_ and _Krvavica_ were analysed, to the best of our knowledge, for the first time. The aim of this work was: (1) to investigate the volatile profile and content of several non-volatile (especially those biologically active) compounds; as well as to (2) assess antioxidant activity of hydrophilic oil fractions in DPPH test; and (3) to compare the characteristic of _Masnjaca_ and _Krvavica_ oils with the oil obtained from the popular Italian variety _Leccino_. The _Leccino_ variety has been used as the reference since it is established olive variety in the major olive growing countries and it is the most present foreign variety in Croatia.