Potential of selected Portuguese cultivars for the production of high quality monovarietal virgin olive oil

The effect of cultivar and ripeness stage on the potential nutritional value of monovarietal extra virgin olive oils (MEVOOs) obtained from Cordovil, Carrasquinha, Verdeal, and Negrinha do Freixo cultivars was investigated. MEVOOs produced were characterized by high oleic acid (72–83%), tocopherol (182–530 mg/kg), and phenolic compounds (326–1110 mg/kg) content and by a similar polyphenolic profile. 1‐Penten‐3‐one was found to be the compound with the highest contribution for the aroma of the four MEVOO, related to bitter, pungent, and leaf attributes. MEVOO from Verdeal cultivar showed the best performance in terms of the composition: the highest yield of oil, the highest content of oleic acid, high tocopherol, polyphenol and sterol content, and the lowest content of linoleic acid. These characteristics give to these MEVOO not only a great oxidative stability but also interesting properties from the health point of view. MEVOO obtained with fruits at the maturity index of around 4 were in general richer in beneficial minor compounds. MEVOO produced were discriminated by variety and ripeness stage, using a stepwise linear discriminant analysis. This discrimination will in the future enable the prevention of adulteration of these monovarietal olive oils with specific nutritional composition with other olive oils. Practical implications: High‐quality MEVOOs have recently been introduced in the market, which for growers is a practical way to differentiate and increase the commercial value of extra virgin olive oil. The quantification of major and minor olive oil compounds in monovarietal olive oils represents an objective way of predicting the sensory characteristics, stability, and potential health benefits of the oils, as well as preventing their adulteration with other olive oils. This study will help in the selection of olive varieties during the maintenance or development of new olive orchards and also to select optimum harvest period for these varieties, in order to obtain MEVOOs with the maximum quality and health benefits for consumers.     

Bioactive Compounds of Portuguese Virgin Olive Oils Discriminate Cultivar and Ripening Stage

The presence of different bioactive compounds in virgin olive oil affects its nutritional, oxidative and sensorial properties. Phenolic compounds are olive endogenous bioactive compounds highly susceptible to degradation. Olive endogenous oxidoreductases, mainly polyphenol oxidases (PPO) and peroxidases (POD), may play an important role on the profile of bioactive compounds in olive oil by promoting oxidation of phenolic compounds. The aim of this study was to evaluate if changes on PPO and POD activities in olive fruits from two Portuguese cultivars (Olea europaea, cv ‘Cobrançosa’ and cv ‘Galega Vulgar’) are related with the composition of their olive oils, especially phenolic compounds. Pattern recognition techniques [principal component analysis (PCA), cluster analysis (CA), and discriminant analysis (DA)] were used for multivariate data analysis. Olive oils characterized by their FA composition were grouped by cultivar. When olive oils were characterized by their phenolic composition, green pigments, and enzymatic activities in fruits, they could be discriminated by olive ripening stage. Along ripening, PPO activity was only detected in the fruit mesocarp of both cultivars and POD activity was mainly detected in the seeds. The POD activity, as well as vanillin and gamma‐tocopherol contents in olive oil increased with the ripening index. Conversely, higher PPO activity in fruits at early ripening stages together with higher levels of total phenols, green pigments, beta‐tocopherol, hydroxytyrosol and p‐coumaric acid in olive oils were observed. The ripening stage of fruits showed to be a key factor on the amount and profile of bioactive compounds of olive oil.     

Characterization of Extra Virgin Olive Oil from Southern Brazil

Six olive oils extracted from the cultivars Arbequina, Arbosana, Coratina, Frantoio, Koroneiki, and Picual from 2017 and 2018 harvests, cultivated in Pinheiro Machado, Rio Grande do Sul, Brazil, are evaluated for standard oil composition parameters and bioactive constituents (pigments, tocopherols, and phenolic compounds). Multivariate principal component analysis (PCA) and univariate ANOVA and Fisher's LSD test are used to verify the effect of cultivar and harvest year on oil composition. Olive oil composition met extra virgin olive oil (EVOO) standard parameters and is influenced by both cultivar and harvest year. EVOO produced in 2018 has greater chlorophyll, caffeic acid, ligstroside aglycone, hydroxyoleuropein aglycone, syringic acid, and hydroxytyrosol acetate contents than the EVOOs from 2017. Linoleic acid, ferulic acid, ligstroside aglycone, and hydroxytyrosol acetate are the variables whose contents most contributed to the differentiation of oils by cultivar in both harvest years. Chemical characterization analyses allow for the differentiation of oil composition based on harvest year and cultivar. Metabolic quality data obtained here support the establishment of a local EVOO profile and the compounds that most contributed to treatment differentiation may serve as markers that can be utilized in determining origin, cultivar, and harvest year. Practical Applications: Olive production in Brazil is recent and is based on European cultivars which have not been bred for the local environmental conditions. Therefore, the measurement of olive oil metabolic quality will determine cultivar adaptability to local edaphoclimatic conditions as well as assist in the establishment of a standard of identity for the product and promote the development of its market. Olive oil produced in Southern Brazil shows high quality, and is especially rich in phenolic compounds. Although harvest year influences oil composition, oil from both harvests meet EVOO standards and cultivar specific metabolic markers are observed. This study provides the foundation for olive producers in Southern Brazil to seek authentication of the geographical origin of olive oil.     

Biochemical Characterization of Turkish Extra Virgin Olive Oils from Six Different Olive Varieties of Identical Growing Conditions

Extra virgin olive oils were extracted from six different major olive cultivars (Gemlik, Ayvalik, Domat, Akhisar, Memecik, Arbequina) cultivated in the Aegean region of Turkey. Fatty acid, sterol and tocopherol compositions were analyzed and the results were compared by multivariate statistical analysis. Olive samples were collected from the same orchard in order to limit the contribution of parameters such as climate, soil quality and agricultural practices to the total variance of chemical composition of olive oils. Principal component analysis (PCA) showed that cultivars can be clearly distinguished on the basis of fatty acid and sterol composition. It is of interest to note that palmitoleic acid content of Arbequina, a Spanish cultivar, is significantly (p < 0.05) higher than the local Turkish cultivars in question and it is the only olive sample whose palmitoleic acid concentration is higher than that of the stearic acid concentration, exhibiting a divergent composition from the local Turkish cultivars. β‐Sitosterol and Δ5‐avenasterol contents of the oils are significantly correlated (r = ?0.989, p < 0.05) and this results in a discriminative axis on the PCA loading plot. Tocopherol composition was relatively insufficient in discriminating the olive varieties. Regarding tocopherol compositions Gemlik cultivar is distinguished from other cultivars with its γ‐tocopherol content, which is in average two times higher than that of other cultivars. The result of the present compositional study provides important data which can be used for olive oil authenticity studies in Turkey.     

Dynamics of Fatty Acids,Tocopherols and Phenolic Compounds Biogenesis During Olive (Olea europaea L.) Fruit Ontogeny

Fatty acids, tocopherols, and phenolic compounds biogenesis from two major Spanish olive cultivars (Arbequina and Manzanilla) were analyzed for the function of the thermal regime during the fruit ontogeny in a non‐Mediterranean environment. Bilinear models characterized the dynamics of fatty acid biogenesis. Regressions between the accumulated thermal time (TT) and the levels of both oleic and linoleic acids showed different responses to temperature of each olive cultivar. After reaching similar absolute maximum oleic acid contents at similar TT, the levels of this fatty acid decreased markedly in cv. Arbequina and its final concentration was 10 % lower than that found in cv. Manzanilla. In both cultivars, concentrations of all tocopherol isoforms were negatively associated with the TT accumulated over the entire oil accumulation period. Dynamics of phenolic compounds biogenesis showed no clear tendencies with TT. Nevertheless, and whatever the stage of fruit development, secoiridoids were the major phenolic components. Results suggest greater sensitivity of fatty acid metabolism to temperature in cv. Arbequina. This fact points out the necessity of appropriate evaluation of the ambient thermal characteristics before introducing this cultivar into new growing environments.     

The Effect of Harvesting Time on Olive Fruits and Oils Quality Parameters of Tortiglione and Dritta Olive Cultivars

Despite the fact that Italy holds the most important olives heritage in the world, with about 800 cultivars, most of them are still underestimated, in particular those from Abruzzo, a region located in the center of the peninsula. The aim of this work is to study the changes in quality parameters of olive fruits and related oils of two autochthonous Abruzzo olive cultivars, Tortiglione and Dritta during ripening (from September to November 2017). Both cultivar and ripening time affect the chemical parameters of olive fruits. Results highlight an increasing trend of the oil content with final values, based on fresh matter, of 38.7 ± 0.3% and 38.1 ± 0.9% for Tortiglione and Dritta, respectively. Olive oils chemical composition is also affected by ripening time and cultivar, with Tortiglione oils resulting generally richer than Dritta oils; on the first sampling time (30th of October) values for total phenolic content, antioxidant activity, and chlorophylls are 803.8 ± 68.2 mg gallic acid equivalent kg⁻¹, 2.7 ± 0.5 mmol trolox equivalent kg⁻¹, and 30.8 ± 1.6 mg pheophytin a kg⁻¹, respectively. Tocopherols seem to be more affected by ripening time than by cultivar, in particular for Dritta. Practical Application : The results on Abruzzo minor olive cultivars indicate that olive fruits and olive oil composition are strongly influenced by both cultivar and ripening time, giving rational indications about the optimal cultivar specific harvesting time and opening interesting opportunities for olive oil producers in a perspective of sustainable production to obtain high quality fruits and oils. The research provides detailed information about Tortiglione and Dritta olive cultivar, useful in the global context of revaluation of Italian minor olive varieties.     

Characterization of Aegean Olive Oils by Their Minor Compounds

This study presents a combined approach of establishing cultivar differences between Aegean olive oils, obtained from economically important olive oil producing cultivars (cv. Ayvalik and Memecik), based on chemometric evaluation of their content and in particular composition of the minor compounds. Evaluation of minor compounds with principal component analysis and linear discriminant analysis (LDA) indicated differentiation according to the cultivars. LDA produced a 100% correct group classification. Moreover, stigmasterol, apparent β-sitosterol and total sterols were found to have the highest discriminating power. Memecik oils were characterized by the highest content of antioxidant compounds (α-tocopherol, phenolic compounds and total phenolic compounds). On the other hand, Ayvalik oil had the highest level of total sterols. The data were analyzed statistically to evaluate the differences according to variety and crop season. The minor compounds of Ayvalik and Memecik oils presented statistically significant differences (p < 0.01) according to variety, except for the hydroxytyrosol and clerosterol content. The amount of α-tocopherol, total phenolic compounds, apparent β-sitosterol and total sterols varied with respect to crop season. A good correlation was observed between the amount of α-tocopherol, total phenolic compounds, apparent β-sitosterol and total sterols and some climatic variables.     

Influence of seasonal conditions on the composition and quality parameters of monovarietal virgin olive oils

The aim of this work was to determine the effect of the climatological conditions of the olive crop season on the composition of monovarietal virgin olive oils obtained from the Arbequina cultivar with special emphasis on the phenolic fraction, its percent distribution, and related oil quality parameters such as oxidative stability and bitter index. The main differences were due to freeze injuries caused by low temperatures in December 2001. The levels of chlorophylls and carotenoids in olive oil or pulp from frost-damaged olive trees were lower as a consequence of faster ripening. The olive oil extracted from frost-damaged olive pulp had lower contents of secoiridoid and especially lower levels of 3,4-DHPEA-EDA (the dialdehydic form of elenolic acid linked to hydroxytyrosol). In the following crop seasons, a significant increase in phenolic compounds, especially in secoiridoid derivatives such as 3,4-DHPEA-EDA, was observed. This increase may be due to the fact that olive trees that suffered frost damage in December 2001 were more sensitive to stress caused by the water deficit during summer in the subsequent crop seasons, which is usual in this olive-growing region. Moreover, important correlation coefficients were observed between the main secoiridoid derivative compound (3,4-DHPEA-EDA) and oxidative stability and the bitter index.     

Characterization of Iranian Virgin Olive Oil from the Roodbar Region: A Study on Zard,Mari and Phishomi

The aim of this study is to describe the physicochemical properties of Iranian virgin olive oil (Zard, Mari and Phishomi) cultivated in Roodbar, Gilan. There were statistically significant differences for most of the parameters (P < 0.05). The acidity and peroxide value were in the limit established for classification as extra virgin olive oil. The oil of Zard had the highest amount of monounsaturated fatty acids followed by Mari and Phishomi oils. Mari oil proved to have the minimum value of polyunsaturated fatty acids, and the highest amount of phenolic compounds and oxidative stability. The oil of Phishomi had the maximum amount of chlorophylls and carotenoids and therefore it had the highest color index. There were no significant differences between the cultivars regarding the refractive index (1.469 at 20 °C for all three cultivars). According to the high content of monounsaturated fatty acids, the lowest amounts of polyunsaturated fatty acids and the highest amounts of phenolic compounds as well as the results of a Rancimat assay, it seems that the quality of the oil of Mari cultivar is better than Zard and Phishomi oils and is also more stable against oxidation.     

Sterol and Fatty Acid Compositions of Olive Oil as an Indicator of Cultivar and Growing Area

Because of the importance of cultivar and growing area on the quality and quantity of extracted olive oil, this study examined the effects of two different growing areas (Qom (subdesertic) and Gorgan (Caspian zone) that have important differences in altitude, latitude, and climatic conditions on the physicochemical characteristics of extracted oils from three common cultivars (Beleydi, Mission and Koroneiki) growing in Iran. Independently of the growing area conditions, Beleydi cultivars showed the lowest values of oil content (16.93 ± 1.55 and 43.54 ± 0.18 % in Qom and Gorgan, respectively) the greatest acidity, even higher than the limits specified by the International Olive Council (IOC) regulations (1.04 and 0.46 % in Qom and Gorgan, respectively), and the lowest oxidative stability (9.0 and 6.7 h in Qom and Gorgan, respectively) among the studied cultivars. All cultivars growing in Qom had lower oil contents, but they had higher oleic acid and β‐sitosterol content and lower PUFA/SFA ratios in comparison with cultivars grown in Gorgan. Therefore, cultivars grown in Qom had higher oxidative stability. Finally, when principal component analysis (PCA) was applied, the fatty acid and sterol profiles could be used to separate olive samples according to their cultivar and growing area, respectively.     

Effect of location on virgin olive oils of the two main Tunisian olive cultivars

The olive oil content in phenolic compounds depends on the variety of the fruit used for its extraction as well as on the predominant climate conditions in the tree cultivation area. Here, we report on the characterization of virgin olive oil samples obtained from fruits of the main Tunisian olive cultivars Chemlali and Chétoui, grown in three different Tunisian locations, Zaghouan (North), Sousse (Center) and Sfax (South). Chétoui olive oil samples obtained from fruits of olive trees cultivated in Zaghouan and Chemlali olive oil samples obtained from fruits of olive trees cultivated in Sousse were found to have a higher mean total phenol content (1004 and 330 mg/kg, respectively). Olive oil samples obtained from fruits of both cultivars had different phenolic profiles and a higher content in 3,4‐DHPEA‐EDA when the olive trees were cultivated in Zaghouan. Both olive cultivars were found to have different responses to environmental conditions. Chétoui olive oil showed decreased oxidative stability when the fruits were obtained from olive trees cultivated in the center of Tunisia (34.8 h) and in Sfax (16.17 h). Furthermore, statistical data showed that the phenolic composition and oxidative stability of Chétoui olive oil varied more by location than those of Chemlali olive oils.     

Effects of Cultivars and Location on Quality, Phenolic Content and Antioxidant Activity of Extra-Virgin Olive Oils

Quality characteristics of extra-virgin olive oils depend on several factors. In order to study the effects of genotype and growing location on olive oil quality, olives from cv. Coratina, Nocellara, Ogliarola, and Peranzana, picked in four locations of the Apulia region (Italy), were crushed by a three-phase system to produce mono-cultivar extra virgin olive oils that were analyzed for acidity, peroxide value, spectrophotometric indices, total phenolic content, phenolic profile and antioxidant activity. The experimental data concerning peroxide value, spectrophotometric indices, phenolic content and profile and antioxidant activity showed great variability among the cultivars grown in the same location and also among the oils produced with olives of the same cultivar but grown in different locations. For each cultivar, no significant differences were found among locations in terms of acidity and ΔK whereas peroxide value, K₂₃₂, and K₂₇₀ differ significantly among locations for both Ogliarola and Peranzana cv. Concerning the phenolic content of Ogliarola cv., no differences were highlighted between the locations whereas the phenolic contents of Peranzana significantly changed as a function of the place of growing. On the basis of these results, the statistical multivariate analysis did not allow the classification into homogeneous groups neither of the oils belonging to the same cultivar nor of those obtained from olives picked in the same location.     

Oil composition of advanced selections from an olive breeding program

Fifteen genotypes coming from crosses between the cultivars Arbequina, Frantoio and Picual were selected on the basis of their agronomic characteristics in a breeding program initiated in 1991. In the present work, the main components of the olive oil of these 15 advances selections have been characterized and compared to their genitors. A wide range of variation was observed for all the fatty acids, minor components and related characteristics evaluated, with significant differences between genotypes for all of them except for β‐tocopherol content. These results confirm the strong genetic influence on olive oil quality previously reported on olive oil cultivar evaluations. The values obtained in the selections have extended the range of variation of their three genitors for all the characters evaluated, except for γ‐tocopherol. Selections UC‐I 7‐8, UC‐I 5‐44 and UC‐I 2‐68 showed the highest average values for tocopherols, polyphenol and C18:1 contents, respectively. Finally, multivariate analysis allowed the classification of genotypes in four groups according to their olive oil composition. Practical applications: Olive oil composition is considered one of the most important objectives in breeding programs aiming at obtaining new olive cultivars. In the last decades olive breeding programs are being carried out in the main olive‐producing countries and several new cultivars and advanced selections have been described. The results of this work provide an initial characterization of virgin olive oils of advanced selections coming from crosses between the cultivars Arbequina, Frantoio and Picual and suggest a strong genetic influence on fatty acid composition, several minor components and related characteristics. These results, together with the agronomic characterization of these selections previously reported, will be used for the final selection of the best genotypes to be registered as new cultivars.     

Characterization and Classification of Extra Virgin Olive Oil from Five Less Well-Known Greek Olive Cultivars

The present study comprises the second part of an ongoing study focusing on olive oil from five less well‐known Greek cultivars for three of which there are no data available in the literature regarding their chemical composition. A total of 74 olive oil samples were collected during the harvesting periods 2012–2013 and 2013–2014. Headspace‐solid phase microextraction was applied to determine the olive oil volatile profile. Fifty‐six compounds were identified and semi‐quantified by CG–MS. Furthermore, fatty acid composition, conventional quality parameters and color parameters were determined in an effort to characterize and differentiate olive oils according to cultivar. All samples were characterized as extra virgin olive oils. Data obtained showed significant differences between the cultivars. Multi‐element analysis in combination with chemometrics resulted in a high classification rate of 86.5 % for the combination of volatiles plus color, 89.2 % for the combination of VC plus FA, and 91.9 % for the combination of FA composition plus color plus CQP.     

Stability of refined olive oil and olive‐pomace oil added by phenolic compounds from olive leaves

Refined olive oil and olive‐pomace oil were enriched with olive leaf phenolic compounds in order to enhance its quality and bring it closer to virgin olive oil. The changes that occurred in the concentrations of pure oleuropein, oleuropein aglycone, hydroxytyrosol acetyl and α‐tocopherol at 400 µg/kg of oil during the storage of refined olive oil and olive‐pomace oil under accelerated conditions (50 °C) were investigated. In a period of 4 months, α‐tocopherol decomposed by 75% whereas less than 40% of the phenols were lost. During storage, enzymatic olive leaf extract hydrolysate that contains two major compounds, hydroxytyrosol and oleuropein aglycone showed the highest antioxidant activity and the lowest detected stability, followed by oleuropein. The oleuropein in olive leaf extracts exhibited similar degradation profiles, reducing by 60–50% and 80% for the olive oil and olive‐pomace oil in 6 months, respectively. The acetylated extract, however, displayed a loss of 10 and 5% in olive oil and olive‐pomace oil, respectively. In the fatty acid composition, an increase in oleic acid and a decrease in linoleic acid were observed. The antiradical activities of the olive oil and olive‐pomace oil enriched with olive leaf phenolic compounds at 400 ppm showed that enzymatic hydrolysate extract had the highest protective effect against oil oxidation. Based on the Rancimat method, the oils with added leaf enzymatic hydrolysate extract had the lowest peroxide value and the highest stability. After 6 months of storage and at 120 °C, the oxidative resistance of refined olive oil and olive‐pomace oil reached 0.71 and 0.89 h, respectively, whereas that of the non‐enriched samples fell to zero.     

Wax Ester Variation in Olive Oils Produced in Calabria (Southern Italy) During Olive Ripening

The wax ester composition of pressed olive oil and its variation during olive ripening were investigated by column chromatography/GC-on column technique. Six compounds were identified: C₃₆, C₃₈, C₄₀, C₄₂, C₄₄ and C₄₆ wax esters, which were grouped as total detected wax esters (TDWEs). The European Union (EU) includes C₄₀, C₄₂, C₄₄ and C₄₆ waxes (TEWEs) as a distinctive characteristic between different categories, with a maximum total content ≤250 mg/kg for an extra virgin olive oil. The International Olive Council (IOC) includes C₄₂, C₄₄ and C₄₆ waxes (TIOCWEs) as a purity parameter, with a maximum total content ≤150 mg/kg for an extra virgin olive oil. The analytical technique proposed by EU and IOC do not separate the wax esters from fatty acids esters with diterpenic alcohols (phytol and geranylgeraniol) that interfere with detected peaks. Although the examined cultivars were grown in the same geographical area and the same agricultural practices were applied to the trees, ANOVA analysis found significant differences among the oils extracted with the same machinery. The oil produced from the Itrana cultivar showed the lowest content in TEWEs (25.00–39.00 mg/kg) and in TIOCWEs (5.67–9.00 mg/kg). Wax content in Leccino and Pendolino cultivars showed a significant tendency to decrease during olive maturation, and a tendency to increase in all other cultivars from the first to the last harvest date when olive pigmentation changed from green to black.     

Comparative study of olive oil quality from Chemlali Sfax versus Arbequina cultivated in Tunisia

The effects of the geographical region on the behavior of the Arbequina olive cultivar (cv) cultivated in the south of Tunisia (in the arid zone of Sfax) was compared to an autochthonous cultivar (Chemlali Sfax). Various olive parameters were analyzed, such as ripening index, pulp/stone ratio, oil contents, and sensory profiles. Most of the quality indices and fatty acid composition showed significant variations among olive cultivars. Arbequina cv is characterized by high oil yield with a less total phenols and pigments content than Chemlali Sfax cv. Cielab spectrophotometer coordinate L*, b*, and a* values show a great difference in olive oil colors. In spite of their low oleic acid contents, autochthonous cultivar presented a higher induction time (6.82 and 2.68 h for Chemlali and Arbequina, respectively) and high contents of phenolic compounds (158.28 and 110.27 mg/kg for Chemlali Sfax and Arbequina, respectively). The most important compounds identified were oleuropein aglycon (45.50 mg/kg), hydroxytyrosol (3.68 mg/kg), 1‐acetoxypinoresinol (6.23 mg/kg) in Chemlali Sfax oil and hydroxytyrosol glucoside (25.15 mg/kg), tyrosol (12.51 mg/kg), and oleuropein aglycon (30.60 mg/kg) in Arbequina oil. Chemlali Sfax also possessed a very bitter taste, whereas the Arbequina had a sweet taste amongst its attributes. The principal component analysis of the results indicated that the geographical region has significantly affected the olive oil quality.     

Quality Characteristics and Antioxidant Activity during Fruit Ripening of Three Monovarietal Olive Oils Cultivated in China

Numerous olive cultivars have been planted in China, mainly to reap the health benefits of olive oil. This study characterized the quality and investigated the antioxidant activity of olives harvested at three different maturation stages, defined by the skin color of the olives (black, purple, and green), from three newly introduced olive cultivars (Barnea, Manzanilla and Kadesh) grown in China. The oleic acid content of olives from all three olive cultivars decreased significantly during maturation, whereas the linoleic acid content increased. The highest content of total phenols was recorded in Manzanilla cultivar (284.94 mg kg⁻¹), whereas the lowest was recorded in Kadesh cultivar (134.82 mg kg⁻¹). In addition, a total of 13 individual phenolic compounds were obtained, and their concentrations were significantly influenced by the cultivar and maturity (P < 0.05). Secoiridoids were the main group of phenolic compounds, but their quantity decreased during maturation. The content of secoiridoids in the Manzanilla cultivar was significantly higher than that of the Barnea and Kadesh cultivars. In general, a significant decrease (P < 0.05) in the values of antioxidant activity and the contents of pigments, α-tocopherol, and squalene occurred during maturation. Furthermore, principal component analysis was used to classify the nine olive oil samples according to the cultivar and ripening degree.     

Chemical Composition of Turkish Olive Oil––Ayvalik

Although large amounts of olive oil are produced in Turkey, not much information on its chemical composition is available in the literature to date. The aim of this study was to evaluate the chemical composition of commercial olive oils produced from the Ayvalik olive cultivar in Canakkale, Turkey. Five different samples corresponding to the olive oil categories of extra virgin (conventional, extra virgin olive oil (EVOO), and organic extra virgin olive oil (OGOO) production), virgin olive oil (OO-1), ordinary virgin olive oil (OO-2) and refined olive oil (RFOO) were evaluated. Olive oils were collected from two consecutive production years. According to the free fatty acids, the absorbance values (K₂₃₂ and K₂₇₀), and peroxide values of all the samples conformed to the European standards for olive oil. The level of oleic acid was in the range of 68–73%; while the linoleic acid content was significantly lower in the refined olive oils. The tocopherol and polyphenol content was in the lower range of some European olive oils. However, pinoresinol was a major phenolic compound (5–77 mg/kg depending on the oil category). Its content was markedly higher than in many other oils, which would be a useful finding for olive oil authentication purposes.     

The Influence of Growing Region, Cultivar and Harvest Timing on the Diversity of Australian Olive Oil

The quality indices and chemical composition of ten common olive cultivars grown in different regions of Australia were evaluated to determine the diversity of olive oils produced in Australia. Olives from trees from different environments including warmer climates in the north to colder climates in the south were sampled at two different stages of maturity over 2 years. The oil was extracted and standard methods were used to analyse the oil. Oleic acid content ranged from 83.4% in the Picual cultivar grown in Tasmania to 54.5% in Arbequina grown in northern New South Wales/southern Queensland. The Barnea cultivar, which is very commonly grown in Australia, was above 4% for campesterol content, regardless of the region in which it was grown. Parameters, such as palmitic acid, oleic acid, linoleic acid and wax content were found to be significantly affected by growing region for some cultivars. This study shows the growing conditions for olive in Australia gives rise to a diverse range of olive oils.