2.7. Olive oil. Introduction

Transcription

1 Research Signpost 37/661 (2), Fort P.O. Trivandrum Kerala, India Plant Lipids Science, Technology, Nutritional Value and Benefits to Human Health, 2015: ISBN: Editors: Grażyna Budryn and Dorota Żyżelewicz 2.7. Olive oil Institute of Food Technology, Faculty of Food Science and Nutrition at the University of Life Sciences in Poznań, Wojska Polskiego 31, Poznań, Poland Abstract. Olive oil, especially virgin olive oils has been appreciated and consumed for centuries all over the world. This chapter describes the world market and economic situation of olive oil, its qualitative categorization, flavour attributes and production stages with their consequences for the quality. Also, the aspects of the chemical composition (fatty acid and minor compounds compositions), and associated with it nutritional and health benefits are shown. Particularly, the consumption of olive oil impact on the incidence of cancer, cardiovascular disease and other civilization diseases has been emphasized. Also, indicated areas, which require further studies, mainly on the role of olive oil in medicine and pharmacy, have been presented. Introduction Olive oil is one of the most representative components of the traditional Mediterranean diet, consumed for centuries. Its worldwide importance, and therefore consumption and production, are constantly increasing. Due to its composition, health benefits, and sensory value, this plant oil is very appreciated and recognized throughout the world. Particular attention is paid Correspondence/Reprint request: Dr., Institute of Food Technology, Faculty of Food Science and Nutrition at the University of Life Sciences in Poznań, Wojska Polskiego 31, Poznań, Poland

2 148 to the composition of fatty acids (mainly high oleic acid content) and the presence of minor compounds, such as polyphenols, phytosterols, and squalene. Quantitative and qualitative composition of olive oil influences its properties and depends on the conditions and the methods of production, which is a multistep process. The olive oil processing includes cleaning, grinding, malaxing, extraction (by pressing, centrifugation and/or percolation), decantation and refining, if necessary. After preparation, the qualitative assessment and qualification on the basis of specified indicators is performed. Appraised are inter alia the free acidity, flavour, colour, peroxide value and absorbency in UV. On this basis, the various classes of olive oil were specified, such as extra virgin and virgin olive oil, olive oil, refined olive oil, olive-pomace and refined olive-pomace oil. The most appreciated of them are the first two oils, which are produced in the mildest conditions (by cold-pressing) and thus have the highest value. These oils are characterized by a higher content of valuable minor compounds, as well as better sensory qualities. The increasing consumption of olive oil is associated with a growing awareness of its health-promoting properties. These health benefits are primarily related to the prevention and/or treatment of certain diseases, among which are mentioned cardiovascular diseases, inflammations, diabetes, and obesity. Some mechanisms of olive oil compounds action on the human body have been confirmed by insightful studies, while the others require thorough explanations. The olive oil market Olive oil is a food product, the production and consumption of which are primarily associated with the Mediterranean countries (Table 1., Table 2.);their origins are dated back to about 5000 years ago [1-6]. Table 1. World olive oil average production and consumption ( /2014) [1, 2]. Production Consumption Country Average Average Percentage Percentage (% Country (1 000 tons) (1 000 tons) (%) UE UE Tunisia USA Syria Turkey Turkey Syria Morocco Morocco Other Other Total Total

3 Olive oil 149 Table 2. UE olive oil average production and consumption ( /2014) [3, 4]. Production Consumption Country Average Percentage Average Percentage Country (1 000 tons) (%) (1 000 tons) (%) Spain Italy Italy Spain Greece Greece Portugal France Other Portugal Total Other Total Nearly 72% (about thousand tons) of world production of this plant oil in the last years includes the countries of the European Union [1]. First and foremost is Spain, then Italy, Greece and Portugal, which generate 59.1%, 22.2%, 15.4% and 2.8% of the EU olive oil production (42.4%, 15.9%, 11.1% and 2.0% of world production) [1, 3]. Except those European countries mentioned above, significant shares in the global production of olive oil have Tunisia (5.8%), Syria (5.6%), Turkey (5.2%) and Morocco (3.8%) [3]. Despite large fluctuations in the level of production in each country, since 1990 the growing tendency has been observed: for the UE from to thousand tons (about 132.3%) and for whole world from to thousand tons (about 113.2%) [1, 3]. In addition to the increasing olive oil production, an increased number of its producers has been observed. In recent years ( /2014), in the olive oil market Australia, Chile, Saudi Arabia, Albania, Slovenia, and Cyprus have appeared [1, 3]. The EU countries are also leading in the consumption of this food product (61.8% of global consumption, thousand tons) [2]. The highest consumption of olive oil has been observed in Italy and Spain, further in Greece, France and Portugal (respectively: 36.2%, 29.9%, 12.4%, 6.0% and 4.4% of UE consumption and 22.4%, 18.4%, 7.6%, 3.7% and 2.7% of global consumption) [2, 4]. A large global consumption has also been observed in the case of the USA (9.2%), Turkey (4.2%), Syria, (4.0%) and Morocco (3.3%) [2]. Similarly to its production, since 1990 the increase in its consumption has been observed: for the UE from to thousand tons (about 58.2%) and for whole world from 1666,5 to 3056,5 thousand tons (about 83.4%) [2, 4]. As expected, countries which are the major olive oil producers are also the leading exporters (Table 3., Table 4.). Approximately 65.6% of world

4 150 Table 3. World olive oil average exports and imports ( /2014) [7, 8]. Exports Imports Country Average Percentage Average Percentage Country (1 000 tons) (%) (1 000 tons) (%) UE USA Tunisia UE Turkey Brazil Syria Japan Argentina Canada Other Other Total Total Table 4. UE olive oil average exports and imports ( /2014) [9, 10]. Exports Imports Country Average Percentage Average Percentage Country (1 000 tons) (%) (1 000 tons) (%) Italy Italy Spain Spain Portugal France Greece Portugal Other Other Total Total exports applies to the EU countries (446.8 thousand tons), of which the main exporters are Italy and Spain, and then Portugal and Greece with respectively 45.7%, 41.2%, 9.2% and 2.7% of UE export (30.0%, 27.1%, 6.0% and 1.8% of global export) [7, 9]. Other significant world exporters are Tunisia, then the Middle East countries as Turkey and Syria, and the representative of South America Argentina. Their average level of global exports amounted to 19.1%, 3.4%, 3.1% and 2.4% [7]. The main importer of olive oil is the USA (38.6%), followed by the UE countries (16.0%) including Italy, Spain, France and Portugal with global imports on the level 11.3%, 3.4%, 0.8% and 0.2% (70.8%, 21.5%, 4.8% and 1.2% of UE imports) [8,10]. At the forefront of olive oil importers are also Brazil (8.0%), Japan (5.5%) and Canada (5.1%) [10]. Part of the largest olive oil producers, as Italy and Portugal, doesn t cover the national consumption (their production is 69.2% and 72.2% of consumption respectively), hence their high position among importers of this food product. A large disparity is observed in the case of one of the

5 Olive oil 151 Mediterranean countries - France, the production of which (5.3 thousand tons) represents only 4.9% of consumption. Therefore, in order to meet the national consumption, France is one of the main UE importers [3, 4, 10]. Chemical composition of olive oil The chemical composition of olive oil is influenced by many factors, such as cultivar (genetic factors), environmental, grooving, and production conditions. For this reason, the large regional differences in composition, aroma, and quality of olive oil can be observed [11, 12]. All composites of olive oil can be categorized into two groups: major and minor compounds. The first group includes triacylglycerols (TAG), subsequently other glycerides as mono- (MAG) and diacylglycerols (DAG) and free fatty acids (FFA) [13]. The health, nutrition, and quality properties of olive oil are mainly caused by unique fatty acid composition, of which the most abundant are: oleic ( %), palmitic ( %), linoleic ( %), stearic ( %), palmitoleic ( %) and linolenic ( %) acids (Table 5.) [12-15]. The composition of fatty acids is strictly limited by the International Olive Council and Codex Alimentarius [14-16]. Compounds such as phospholipids, waxes, carotenoids, chlorophylls, tocopherols, sterols, phenols, aliphatic alcohols, hydrocarbons (e.g. squalene) are classified in the second group-minor compounds [13, 17]. This chemically heterogeneous group is defined as unsaponifiable matter, which constitutes about % of olive oil [17]. Plant sterols (phytosterols) are the most frequently occurring group of minor compounds, and constitute around 20% of saponifiable fraction of olive oil [11, 13]. According to references [14, 15], the content of total sterols should amount to at least 1000 mg/kg for virgin olive oil, olive oil and refined olive oil, 1800 mg/kg for refined olive-pomace oil and 1600 mg/kg for olive-pomace oil. The four major classes of olive oil sterols have been specified: common sterols (4-desmethylsterols), 4α-methylsterols, triterpene alcohols, and triterpene dialcohols [16].These first occur in free or esterified form and also as sterylglucosides and lipoproteins. The main sterol of olive oil is β-sitosterol (732 mg/kg), and other major representatives of these compounds are Δ 5 - avenasterol (78 mg/kg), Δ 7 -avenasterol (30 mg/kg) and campesterol (19 mg/kg) [16, 17]. Stigmasterol (0.5 mg/kg), cholesterol (0.5 mg/kg), brassicasterol (0.5 mg/kg), Δ 7 -stigmasterol (0.5 mg/kg) ergosterol, sitostanol were found in minor amounts [16, 17]. 4-methylsterols are present in olive oil in smaller quantities ( mg/kg) and their main representatives are obtusifoliol, gramisterol, citrostadienol and cycloeucalenol [16].

6 152 The quantitative and qualitative phytosterol composition (which is characteristic of each type and grade of olive oil) mostly depends on variety and growing area of fruits and oil production process. Therefore, the sterol profile may be used for authenticity and quality control [11]. Δ 5,23 - stigmastadienol is an example of use in quality control and detection of virgin olive oil falsification, because its presence indicates the refining process. Also, the increasing content of Δ 5,24 -stigmastadienol with decreasing concentration of Δ 5 -avenasterol might indicate that the olive oil was refined [13]. Table 5. Fatty acid composition of different categories of olive oil (% total fatty acids) [14, 15]. Fatty acids Extra Virgin olive oil Virgin olive oil Olive oil Refined olive oil Olive-pomace oil Refined oil-pomace oil % total fatty acids Myristic acid C14: Palmitic acid C16: Palmitoleic acid C16: Heptadecanoic acid C17: Heptadecenoic acid C17: Stearic acid C18: Oleic acid C18: Linoleic acid C18: Linolenic acid C18: Arachidic acid C20: Eicosenoic acid 20: Behenic acid C22: Lignoceric acid C24: trans isomers C18: trans isomers C18:2 + C18: The total amount of triterpene alcohols (4,4-dimethylsterols) usually ranges from 350 to 1500 mg/kg and is determined by cultivar, crop, and processing conditions. Compounds belonging to this group are: β-amyrin, cycloartenol, 24-methylenecycloartanol, germanicol and butyrospermol. The big impact on its composition has refining process [16].The sterol fraction is often analysed with triterpene dialcohols, which includes uvaol (Δ12-ursen- 3β,28-diol), and erythrodiol (homo-olestranol, 5α-olean-12-ene-3β, 28-diol) [11, 13, 16]. The total content of these compounds in virgin olive oil, refined olive oil, and olive oil should not exceed 4,5% of total sterols, which was legally established [11, 13, 14]. In addition to the ability to detect olive oil falsification, triterpene dialcohols have proven health benefits [13].

7 Olive oil 153 Tocopherols are present in virgin olive oil in quantities of mg/kg, wherein 52-87% of this amount is α-tocopherol, 15-20% β-tocopherol, and 7-23% γ-tocopherol [13]. The content of tocopherols in olive oil may be applied as an indicator of purity and quality of this plant product. Particular classes of olive oil differ from each other in tocopherols content, which is due to the destructive influence of refined process. Furthermore, a lower content of tocopherols in virgin olive oil than in olive pomace oil, which has been produced from olive pomace (α-tocopherol: VOO mg/kg, OPO mg/kg; β-tocopherol: VOO 0 17 mg/kg, OPO 1 6 mg/kg and γ-tocopherol: VOO 0 31 mg/kg, OPO: 0 15 mg/kg) was observed [13, 17]. These antioxidants are significant from the health and nutritional point of view, because they have activity and properties of vitamin E [13, 17]. Phenolic compounds are of great importance for health properties, sensory profile, and oxidative stability of olive oil. Several studies have confirmed their importance in the treatment and prevention of cardiovascular diseases and cancer. In addition, polyphenols are also responsible for the formation of sensory attributes (e.g. bitterness, pungency) and may be an indicator of the olive ripeness and olive oil quality [13, 18, 19]. Polyphenols are highly diversified in terms of chemical structure and therefore have been divided into following groups: tyrosol, hydroxytyrosol and their derivatives, which are the most abundant, then derivatives of 4-hydroxycinnamic, 4-hydroxybenzoic and 4-hydroxyphenylacetic acids, next flavonoids and finally lignans [20]. The phenolic compound of the highest importance is oleuropein (the ester of elenolic acid and 3,4-dihydroxyphenyl ethanol), whose content can reach 140 mg/g of fresh olives dry matter [21]. The colour of olive oil depends largely on the degree of ripeness and variety of the olives, and also on the production and storage conditions of oil. Compounds belonging to the chlorophylls and carotenoids are responsible for green-yellow colour of olive oil. First of them (e.g. pheophytin a and b, pheophorbides) give a greenish tone, and compounds belonging to the second group of pigments (e.g. β-carotene, lutein) are yellow and orange. Concentration of carotenoids usually does not exceed 10mg/kg. Among them predominant is lutein, which belongs to the xanthophylls, and β-carotene [13]. Carotenoids due to its antioxidant properties are responsible for the stabilization of colour, as well as protection of olive oil against photooxidation [13, 18]. Hydrocarbons are not numerously represented group of components of olive oil. The main hydrocarbon of this food product is a linear triterpene squalene and its content ranges from 1 to 7 g/kg [13, 17].This compound with antioxidant properties is significant for the human health because it is an important lipid component of the skin cells responsible for its

8 154 moisturizing, has a cardioprotective activity, lowers blood levels of cholesterol and TAG and promotes prevention of breast cancer [22]. The production process of olive oil Olive oil is produced from fruits of the olive tree (Olea europaea L.). The production process of this plant oil is a multistep process that has been improving over the centuries (Figure 1.). In the first step olives are carefully cleaned and some leaves, stems, and another contaminants and foreign materials are removed [23, 24]. Then follows grinding of the fruits by stone or hammer mills, whereby olive cells are fleshed, oil is released and the paste is formed. Sometimes olives are destoned, but producers often neglect this step. Although destoning may contribute to the increasing of polyphenols content and oxidation stability, the disadvantages associated with it are usually being emphasized. Inclusion of an additional manufacturing step requires expensive equipment and longer mixing time during which oxidation processes occur more easily [23,24]. Figure 1. Steps of olive oil production [15, 23, 24].

9 Olive oil 155 After grinding, the olive paste yields malaxation or mixing for min at C, during which increases the oil availability and unbroken cells are destroyed. During this production step, enzymatic processes take place and the olive oil flavour is formed. For this reason, the operating conditions of this process are very important for the quality of the final product. The rising mixing time contributes to the growth of the rate of flavour improvers but also accelerates oxidation processes. The rising temperature increases total polyphenol content but only to a point. Heating and water addition to the paste improves the efficiency of oil extraction, but, unfortunately, at the expense of quality [23]. To remove the solid material from the oil, the gravitational, pressing or centrifugal methods are used. The traditional separation techniques are based on pressing the paste by screw presses and squeezing it on mats or in bags. An important step has been the invention of a hydraulic press, which is more reliable and effective than the traditional presses and is successfully used today [23, 24]. Due to the fact the pressing is low productive and time-consuming, the centrifuges are more frequently used. This method is based on taking advantage of differences in densities of the individual components of the olives. There are two methods of olive paste centrifugation: two- and threephase, wherein the first one separates the oil from the wet paste and the second one separates oil, water and solid material (this method requires the addition of water). Both methods are advantageous from an economic point of view, because they are effective and require lower operating costs. Their disadvantages are the need of acquisition of expensive equipment, generation of significant amount of wastewater and lower oxidative stability and bitterness (worse aroma profile) due to the lower concentration of polyphenols in oil. An alternative to centrifugation is cold percolation (selective filtration process), which uses the difference in surface tension of oil and water [23, 24]. To perform the extraction it is required to use the Sinolea equipment with steel plates. During immersion in the paste, steel plates are covered with oil, which is further removed by reciprocating movements and the presence of scrapers. This process is repeated several times, until most of the oil (70-75%) will be extracted from the paste. The use of percolation is not conductive to loss of polyphenols in olive oil since no water is added. Disadvantages of this process are lower yield of oil, higher sensitivity to oxidation and an indication of connection with another extraction technique (usually centrifugation) [23, 24]. To complete the production process of olive oil, the final centrifugation and sedimentation are used. These treatments, sometimes in conjunction with filtration, are aimed to remove residual water and solids before bottling [23, 24].

10 156 Classification of olive oils On the basis of quality, chemical composition and method of production, olive oil has been categorized. The content of free fatty acids (FFA) is very important for qualification each category, because the less the content of FFA, the better the oil quality. Based on the categorization of the International Olive Oil Council (2011), the following types of olive oil have been listed [15, 18]: a) Virgin olive oils oils obtained from olives by the use of physical techniques (e.g. washing, pressing, centrifugation, filtration, decantation) under certain conditions (especially of temperature), with the exception of chemical processes. Extra virgin olive oil (EVOO) virgin olive oil, free acidity dose of which does not exceed 0.8% (0.8 grams of oleic acid in 100 grams of oil) and which complies with the other quality criteria for this category (e.g. flavour, colour, peroxide value, absorbency in UV). Virgin olive oil (VOO) virgin olive oil, free acidity of which does not exceed 2.0% (2.0 grams of oleic acid in 100 grams of oil) and which complies with the other quality criteria for this category. Ordinary virgin olive oil (OVOO) - virgin olive oil, free acidity of which does not exceed 3.3% (3.3 grams of oleic acid in 100 grams of oil) and which complies with the other quality criteria for this category. Lampante virgin olive oil virgin olive oil free acidity of which exceeds 3.3% (3.3 grams of oleic acid in 100 grams of oil) or which does not comply with any of the quality criteria for this category. Therefore, it is not fit for consumption but it is intended for refining [15]. b) Refined olive oil (ROO) olive oil for the production of which a refining process is used, without interfering in the initial glyceridic structure. Its free acidity does not exceed 0.3% (0.3 grams of oleic acid in 100 grams of oil) and it complies with the other quality criteria for this category. Through the removal of flavour and colour compounds, this oil becomes neutral [15]. c) Olive oil (OO) - olive oil that is a mixture of refined olive oil and virgin olive oils. Its free acidity does not exceed 1,0% (1,0 gram of oleic acid in 100 grams of oil) and it complies with the other quality criteria for this category [15]. d) Olive-pomace oils oils obtained from the olive pomace through the use of physical methods and solvent extraction, with the exception of reesterification and blending with other types of oils.

11 Olive oil 157 Refined olive-pomace oil (ROPO) - olive-pomace oil for the production of which a refining process is used, without interfering in the initial glyceridic structure. Its free acidity does not exceed 0.3% (0.3 gram of oleic acid in 100 grams of oil) and it complies with the other quality criteria for this category. Olive-pomace oil (OPO) olive-pomace oil that is a mixture of refined pomace-olive oil and virgin olive oils. Its free acidity does not exceed 1.0% (1.0 gram of oleic acid in 100 grams of oil) and it complies with the other quality criteria for this category. Crude olive-pomace oil olive-pomace oil intended for technical purposes or refining and then consumption, which complies with the quality criteria for this category [15]. Olive oils are subjected to qualification just after production. However, there is no guarantee that the classified product will retain its quality factors on the same level after reaching the consumer [18]. The olive oil quality is closely related with its flavour. The composition of taste and aroma compounds may induce a positive or negative sensation [18, 25]. The positive attributes include: Fruity the primary olfactory positive attribute associated with oil from fresh, green and healthy fruits, either ripe and unripe. In the case of olive from unripe olives, this sensation is defined as grassy or green. The fruity attribute is positively correlated with content of C5 and C6 volatile compounds [18, 25]. Bitter - the main taste olive oil sensation derived from green or changing colour olives. This attribute is positively correlated with content of 1-penten-3-one and negatively correlated with content of cis- 3-hexen-1-ol and hexanal [18, 25]. Pungent - biting sensation of olive oil from unripe olives, which were collected at the beginning of the year. This attribute is perceived in the whole of oral cavity, especially in the throat. It is positively correlated with content of 1-penten-3-one and negatively correlated with content of trans-2-hexenal and hexanal [18, 25]. Negative attributes (defects) are: Fusty - flavour derived from oil or olives, that have been stored under anaerobic fermentation conditions. This defect is associated with the content of propanoic acid and butanoic acid [18, 25]. Musty-humid - flavour derived from the fruits, which were stored under conditions of low temperature and high humidity. These fruits are infected with large amount of fungi and yeast. This defect is positively

12 158 correlated with content of short chain fatty acids and negatively correlated with content of trans-2-hexenal [18, 25]. Muddy sediment flavour, which is a result of long contact of oil and sediment [18, 25]. Winey-vinegary flavour, which is formed by aerobic fermentation of olive oil. This defect is associated with the content of acetic acid, ethyl acetate and ethanol [18, 25]. Metallic flavour, which is a result of long contact of olive oil and metallic elements during grinding, malaxing, centrifugation, pressing and storage. This defect is associated with the content of 1-penten-3-one [18, 25]. Rancid olive oil flavour, which arises as a result of oxidation processes. This defect is associated with the content of unsaturated aldehydes [18, 25]. Health benefits and nutritional value of olive oil Olive oil (especially virgin olive oils) has been appreciated due to its sensory value, nutritional properties and health benefits arising from its chemical composition. Conducted studies indicate the beneficial effects of this component of the traditional Mediterranean diet in cardiovascular diseases, metabolic syndrome, inflammations, diabetes, obesity, cancer and aging (Table 6.) [26,27]. Table 6. Health benefits of olive oil compounds [26-35]. Spectrum of activity Hypertension Dyslipidemia Other cardiovascular diseases Inflammation Oxidation and oxidative stress Cancer Obesity and diabetes Immune system function Component of olive oil Fatty acids composition (high content of oleic acid, low content of SFA), phenolic compounds, hydroxyl-oleic acid Phenolic compounds (oleuropein, hydroxytyrosol) Fatty acids composition (high content of oleic acid, low content of SFA), linoleic acid, oleocanthal Phenolic compounds, oleocanthal Oleic acid, phenolic compounds (oleuropein, hydroxytyrosol), tocopherols Phenolic compounds, squalene Fatty acids composition (high content of oleic acid, low content of SFA), phenolic compounds, oleoiletanolamide Fatty acids composition, phenolic compounds

13 Olive oil 159 A positive impact on the cardiovascular system has been assigned to olive oil, due to its unique composition. The Seven Countries Study has proven that in the countries with high intake of this food product there has been low coronary heart disease death rate [28]. The results of the casecontrol study, which was conducted in Navarra in Spain, suggest positive impact on reducing the risk of coronary disease [28]. Also, the Lyon Diet Heart Study including a group of patients after myocardial infarction, has provided evidence of the health-promoting effect of the Mediterranean diet and rich in oleic acid and linoleic acid olive oil [29]. Several studies have shown that minor compounds, such as phenolic compounds (e.g. oleuropein, hydroxytyrosol) have a protective function and, additionally, due to predominant content of monounsaturated fatty acids (MUFA) above the saturated fatty acids (SFA), regular intake of this plant oil helps to reduce the level of low-density lipoprotein (LDL) and triglycerides and increase highdensity lipoprotein (HDL) [28].These properties are very significant in prevention and treatment of atherosclerosis and dyslipidemia. The diet rich in olive oil (such as the Mediterranean diet) contributes to the improvement of endothelial function, which is responsible for the proper blood vessels tension and, therefore, appropriate blood pressure. The blood pressure reduction was due to the modification of fatty acid composition in blood vessels cell membranes and thereby to changing its functionality [28, 29]. Also, it is worth emphasizing that due to the presence of strong antioxidants, such as oleuropein (the ester of elenolic acid and 3,4-dihydroxyphenyl ethanol) and hydroxytyrosol the LDL cholesterol oxidation is inhibited. Additionally, oleocanthal through COX-1 and COX-2 suppression is responsible for the anti-inflammatory effect and reduction of monocytes adhesion, which is essential for the atherogenesis prevention [28, 30]. Inflammatory processes are associated with several diseases, including atherosclerosis or rheumatoid arthritis. The results of numerous studies suggested beneficial effect of olive oil on inflammation and immune function (e.g. inhibition of lymphocyte proliferation, activity of natural killer cells). Due to the high oleic acid content, higher resistance of LDL oxidation, decreasing adhesion of monocytes to endothelial, and inhibition of the foam cells formation have been observed. Also, decreased plasma levels of main fibrinolysis inhibitor (PAI-I), von Willebrand factor and thrombomodulin have been proven, which are related to the prevention of coronary disease. The effect of olive oil on the immune system seems to be associated not only with fatty acid composition but also with minor compounds (e.g. phenolic compounds); however, these properties still require confirmation and conduction of more research [31].

14 160 Cancer is one of the main causes of death in civilized countries. In the Mediterranean region, where olive oil is consumed on a regular basis, the lower incidence rates of cancer have been observed. This is explained by a high content of phenolic antioxidants and squalene in this food product. It is considered that these olive oil minor compounds may influence the various stages of tumorgenesis by inhibiting the activation of carcinogens and reducing their bioavailability [32, 33]. Due to their antioxidant properties, the free radical reactions (lipid peroxidation, DNA adduct formation, singlet oxygen scavening), which contribute to the carcinogenesis, are inhibited. Several studies have shown its protective effect against breast, colorectal, prostate, and skin cancer [32]. Diabetes type 2 and obesity are closely associated with metabolic syndrome and unhealthy lifestyle, including inter alia a diet rich in calories, monosaccharides and SFA. Previous studies have suggested a beneficial effect of a diet rich in MUFA, which are contained in olive oil, on insulin sensitivity, β-cells functions, postprandial lipemia and glucose homeostasis, as well as the appearance of diabetic complications [34]. Due to the increased supply of the oleic acid at the expense of SFA, the peroxisome proliferator-activated receptor gamma (PPAR-γ) is also activated, which enhances the insulin action without increasing its secretion and improving lipid metabolism [35]. In recent times, the influence of oleoiletanolamide (OEA) on satiety and frequency of meals has been analysed. This oleic acid derivate in experimental animals studies activates cannabinoid receptors (CB1) and therefore reduces the sense of hunger and decreases the body mass. These results are seen in PPAR- α activation and stimulation of the vagus nerve [35]. The olive oil impact on obesity and diabetes hasn t been precisely confirmed and the mechanisms of its compounds activities require further explanation. Conclusions Olive oil has been valued since ancient times for its health benefits, sensory, and nutritional values. With increasing awareness of the impact of diet on health and the growing Mediterranean diet popularity, increasing olive oil consumption has been observed. The olive oil quality and thus content of valuable nutrients and sensory compounds influence the harvesting, production, and storage conditions. The most desirable and valuable grades of this plant oil are obtained by mild processes (e.g. cold pressing), where negative changes occur to a minimum extent. To meet the growing olive oil market demands, it was necessary to develop methods, which increase the productivity, e.g. centrifugation, higher

15 Olive oil 161 temperature, extraction. After production, this plant oil is subjected to quality assessment and qualification, allowing the consumer to purchase a product with the required properties. The uniqueness and beneficial effects of olive oil are due to the large amount of MUFA, mainly oleic acid ( % of total fatty acids). This compound seems to be the cause of a beneficial influence on the progress and incidence of some civilization diseases, such as cardiovascular disease, diabetes, and obesity. Previous studies also suggest its positive role in inflammatory processes. The advantageous properties of the oleic acid are complemented by the action of compounds with antioxidant properties, which are present in the unsaponifiable matter. Oleuropein, hydroxytyrosol and oleocanthal play an important role in the course of cardiovascular diseases, phenolic compounds support the immune system function, squalene seems to have protective effect on breast, colorectal, prostate and skin cancer, while oleoiletanolamide probably has the ability to regulate food intake by inducing satiety, what may be significant in obesity treatment. Health-promoting effects of olive oil and compounds contained therein are subjects of many studies. Some of them require accurate explanations and confirmation. Olive oil is one of the best-studied plant oils. The acquired knowledge allows to consider it as a valuable food product with a beneficial effect on health. However, further thorough research may make it possible to extend the use of occurring therein compounds in medicine and pharmacy. References 1. International Olive Council (IOC). World Olive Oil Figures-Production. Available: Accessed 2013 Dec International Olive Council (IOC). World Olive Oil Figures-Consumption. Available: Accessed 2013 Dec International Olive Council (IOC). UE Olive Oil Figures-Production. Available: Accessed 2013 Dec International Olive Council (IOC). UE Olive Oil Figures-Consumption. Available: Accessed 2013 Dec Kapellakis IE, Tsagarakis KP, Crowther JC (2008) Olive oil history, production and by-product management. Rev. Environ. Sci. Biotechnol. 7: Zampounis V (2006) Olive Oil in the World Market. In: Boskou D, editor. Olive oil chemistry and technology, Second Edition. Thessaloniki: AOCS Press pp

16 International Olive Council (IOC). World Olive Oil Figures-Exports. Available: Accessed 2013 Dec International Olive Council (IOC). World Olive Oil Figures-Imports. Available: Accessed 2013 Dec International Olive Council (IOC). UE Olive Oil Figures-Exports. Available: Accessed 2013 Dec International Olive Council (IOC). UE Olive Oil Figures-Imports. Available: Accessed 2013 Dec Mendoza MFD, Gordillo CDM, Expóxito JM, Casas JM, Cano MM, Vertedor DM, Baltasar MNF (2013) Chemical composition of virgin olive oils according to the ripening in olives. Food Chem. 141: López-Cortés I, Salazar-García DC, Velázquez-Martí B, Salazar DM (2013) Chemical characterization of traditional varietal olive oils in East of Spain. Food Res. Int. 54: García-González DL, Aparicio-Ruiz R, Aparicio R (2008) Virgin olive oil - Chemical implications on quality and health. Eur. J. Lipid Sci. Technol. 110: Codex Alimentarius Commission (Amended 2013) Standard for Olive Oils and Olive Pomace Oils. Codex-STAN , Rev International Olive Council: Trade Standard Applying to Olive Oils and Olivepomace Oils; COI/T.15/NC No 3/ Rev.7; May Boskou D, Blekas G, Tsimidou M (2006) Olive Oil Composition. In: Boskou D, editor. Olive oil chemistry and technology, Second Edition. Thessaloniki: AOCS Press pp Belitz HD, Grosch W, Schieberle P (2009) Lipids. In: Belitz HD, Grosch W, Schieberle P, editor. Food Chemistry. Berlin: Springer-Verlag pp Kalua CM, Allen MS, BedgoodJr DR, Bishop AG, Prenzler PD, Robards K (2007) Olive oil volatile compounds, flavour development and quality: A critical review. Food Chem. 100: Fregapane G, Salvador MD (2013) Production of superior quality extra virgin olive oil modulating the content and profile of its minor components. Food Res. Int. 54: Boskou D, Tsimidou M, Blekas G (2006) Polar Phenolic Compouns. In: Boskou D, editor. Olive oil chemistry and technology, Second Edition. Thessaloniki: AOCS Press pp Omar SH (2010) Cardioprotective and neuroprotective roles of oleuropein in olive. Saudi Pharm. J. 18: Spanova M, Daum G (2011) Squalene biochemistry, molecular biology, process biotechnology, and applications. Eur. J. Lipid Sci. Technol. 113: Matthäus B (2012) Oil Technology. In: Gupta SK editor. Technological innovations in Major World Oil Crops Vol. 2. New York: Springer Science + Business Media pp

17 Olive oil Kapellakis IE, Tsagarakis KP, Crowther JC (2008) Olive oil history, production and by-product management. Rev. Environ. Sci. Biotechnol. 7: International Olive Council: Sensory Analysis of Olive Oil. Method for the organoleptic assessment of virgin olive oil. COI/T.20/Doc No 15/ Rev.6; November Caramia G, Gori A, Valli E, Cerretani L (2012) Virgin olive oil in preventive medicine: From legend to epigenetics. Eur. J. Lipid Sci. Technol. 114: Harwood JL, Yaqoob P (2002) Nutritional and health aspects of olive oil. Eur. J. Lipid Sci. Technol. 104 (2002) Ruiz-Canela M, Martinez-Gonzalez MA (2011) Olive oil in the primary prevention of cardiovascular disease. Maturitas 68: Perona JS, Cabello-Moruno R., Ruiz-Gutierrez V. (2006) The role of virgin olive oil components in the modulation of endothelial function. J. Nutr. Biochem. 17: Omar SH (2010) Cardioprotective and neuroprotective roles of oleuropein in olive. Saudi Pharm. J. 18: Harwood JL, Yaqoob P (2002) Nutritional and health aspects of olive oil. Eur. J. Lipid Sci. Technol. 104: Owen RW, Haubner R, Würtele G, Hull WE, Spiegelhalder B, Bartsch H (2004) Olives and olive oil in cancer prevention. Eur. J. Cancer Prev. 4: Escrich E, Ramirez-Tortosa MC, Sanchez-Rovira P, Colomer R, Solanas M, Gaforio JJ (2006) Olive oil in cancer prevention and progression. Nutr. Rev. 10: s 40-s Batti Martinez P R, Solanas M, Solfrizzi V, de la Torre-Fornell R, Trichopoulou A, Uceda M, Villalba-Montoro JM, Villar-Ortiz JR, Visioli F, Cardiovascular Diseases 20: Caramia G, Gori A, Valli E, Cerretani L (2012) Virgin olive oil in preventive medicine: From legend to epigenetics. Eur. J. Lipid Sci. Technol. 114: