Characterization Of Olive Oils Research Articles

Chemical characterization of organic and non-organic virgin olive oils

Organic food products have shown to have lower environmental impact and lower presence of chemical residues. Consumers generally have positive attitudes towards organic food because of superior taste, environment- friendliness, health, food safety and animal welfare. During last years, the demand of consumers for organic virgin olive oils have been increased as a result of their high quality image from nutritional and health aspects. In this work sixteen virgin olive oil samples, four obtained by organic and twelve from non-organic cultivation, were analysed by their quality parameters (acidity, peroxide value and UV absorption), fatty acids, sterols and volatile compounds. Qual- ity parameters were not able to discriminate between organic and non-organic samples although significant differences were found in the values of acidity and K270. Fatty acids and sterols content were able to discriminate samples ac- cording to their cultivar but did not show capacity differentiating the samples according to the cultivation system. The results of volatile analysis show that in general terms the organic virgin olive oils showed a higher concentration of volatile compounds, except for the aldehydes, whose concentration was higher in the non-organic oils, and the acids, whose concentration was similar in the both oil classes. The concentration of ketones, aldehydes, and alcohols showed significant variations (p < 0.05) between the two types of oils.

Effect of organic cultivation of Picual and Hojiblanca olive varieties on the quality of virgin olive oil at four ripening stages

In recent years, there has been a remarkable development of organic agriculture worldwide, including in olive cultivation. The objective of this study was to evaluate the physicochemical characteristics and nutritional quality of virgin olive oils extracted from two of the most widespread olive varieties in Spain (Picual and Hojiblanca) at different olive‐ripening stages, grown using organic or conventional methods. The results of this study showed significant differences in the acidity, oxidative stability, tocopherol contents, fatty acid composition and phenol contents of oils from organically and conventionally cultivated olives. However, the variety and the maturity stage of the olives had a greater effect on the physico‐chemical and nutritional parameters than whether the cultivation method was organic or conventional. Due to the growing interest in organic olive oil in the national and international markets, more studies that analyse the effect of organic cultivation on the quality of olive oil are required.This study evaluates the quality characteristics of virgin olive oils extracted from two of the most widespread olive varieties in Spain (Picual and Hojiblanca) at different olive‐ripening stages, grown using organic or conventional methods. The results showed significant differences in the acidity, oxidative stability, tocopherol contents, fatty acid composition and phenol contents of oils from organically and conventionally cultivated olives.

Cross-cultural perception of six commercial olive oils: A study with Spanish and US consumers.

A cross-cultural study was conducted with Spanish and US consumers to gain an insight into the preferred characteristics of olive oils in both countries. Six commercial olive oils (four samples from Spain and two samples from the US) were analyzed by a highly trained panel (descriptive analysis) and also by two consumers' groups (100 consumers from Spain and 100 from the US). Demographic, acceptability, and Just-About-Right data were collected to study the preferences of both groups, and the relationships with descriptive data were explored to determine the drivers of like/dislike. The Spanish extra virgin olive oils and the imported US extra virgin olive oil were characterized by having bitter, pungent, and more green notes, and were preferred by the Spanish consumers. The US consumers liked the bland Spanish refined olive oil, and the Californian olive oil that was characterized by fruity, floral, and sweet notes. The results showed that the Spanish consumers were more aware about olive oil quality in general than their US counterparts, maybe because of a higher usage of the product in Spain. The present study provides essential data which might help producers in designing and promoting olive oils matching US consumers' requirements, an emerging market for this Mediterranean product.

Microbiological characterization of Picholine variety olives and analysis of olive oil produced in traditional oil mills in Morocco

The physico-chemical and microbiological characteristics of olive oil can be affected by both storage time of the olives before milling, and also the manner in which the oil is stored.The aim of this study was to determine the microbiological profile of olives stored for different periods (7, 15 and 30 days) and to examine the olive oils obtained by measuring changes in physico-chemical and microbiological characteristics, including polyphenol contents and antioxidant capacity, after 3 and 6 months storage.In all olive samples, and also in all the corresponding oils, the main micro-organisms found were mesophilic and psychrotrophic bacteria, yeasts and moulds. Enterobacteriaceae were not detected. It was noted that storage produced a significant increase in acidity, peroxide contents and ultraviolet absorbance, as well caused a significant reduction in polyphenol contents and antioxidant capacity.

Methods for PDO olive oils traceability: state of art and discussion about the possible contribution of strontium isotopic tool

Olive oil represents an important ingredient in the Mediterranean diet and is appreciated both for nutritional and sensory properties, often related to geographical origin and cultivar of olive fruits employed. Fraudsters trying to seek financial gain can adulterate the product causing economic repercussions and, sometimes sanitary risks. The “protected designation of origin” (PDO) label insures a relative protection of both consumers and honest producers, since it prescribes production techniques and specific geographical origin, but one of the main problems is to set down objective tools to control these specifications. We reviewed numerous studies using various analytical tools to discriminate PDO olive oils’ geographical origin depending on (1) volatiles compounds, (2) fatty acid and triacylglycerol composition, (3) trace elements, and/or (4) stable isotope ratios, but we highlighted that, despite their efficiency, none of them could provide an irrefutable identification. However, 87Sr/86Sr signature revealed to be an optimal geographical fingerprint in the same purpose for other food products like cereals, orange juice, coffee or alcoholic beverages. Such 87Sr/86Sr studies do not exist on olive oils, probably because of analytical issues, but we propose that developing complementary 87Sr/86Sr studies could be a promising tool to re-enforce the characterization of PDO olive oils.

Consumer discrimination of Chemlali and Arbequina olive oil cultivars according to their cultivar, geographical origin, and processing system

The chemical composition and consumer preferences according to consumer characteristics of virgin olive oils (VOOs) from “Chemlali” and “Arbequina” cultivars were studied in relation to processing system and geographical origin. Statistical analyses revealed significant differences (p &lt; 0.05) among cultivars in % free acidity, K270, and OSI values, pigments, and antioxidant content and in some FAME content. Significant differences were also found according to the processing system in terms of some quality indices, pigments, antioxidant compounds, and OSI values. The effect of processing system on fatty acid composition was almost not significant except for some of them. The effect of the geographical origin was different in relation to the cultivars: For “Chemlali” cultivar, it was significant (p &lt; 0.05) in all studied parameters except for acidity and total polar phenol content. However, for “Arbequina”, the effect was significant (p &lt; 0.05) for K232, pigments, antioxidant compounds and fatty acid composition except for margaric, margaroleic, linolenic, arachidic, and behenic fatty acids. Consumers were able to discriminate between cultivars with more preference for “Arbequina” oil, but only in case of “Chemlali” they could discriminate between the oils from different locations, with significantly more consumer liking for oils from Sidi Bouzid and Sawef. However, they were not able to discriminate between the processing systems.A session of sensory analysis that shows consumer preferences according to consumer characteristics. Consumer preferences are defined as the subjective (individual) tastes and flavors, as measured by the satisfaction that a consumer derives from the consumption of different goods, in this study, the Virgin Olive Oil (VOO). VOO sensory analysis permits the consumer to rank the different oils according to the levels of satisfaction they give the consumer.

Phenolic compounds and antioxidant capacity of virgin olive oil

The characterisation of virgin olive oil from Arbequina, Carrasqueña, Corniche, Manzanilla Cacereña, Morisca, Picual, and Verdial de Badajoz varieties according to the individual phenolic compounds at different ripening stage was carried out. In all olive oil varieties studied, secoiridoid derivatives were most abundant, followed by phenolic alcohols, flavonoids and phenolic acids. The secoiridoid derivatives of hydroxytyrosol were the most important complex phenols for Picual and Carrasqueña, whereas the tyrosol derivatives were the major ones found in Manzanilla Cacereña, and Verdial de Badajoz. For secoiridoid derivatives of hydroxytyrosol and tyrosol, Arbequina was the oil variety showing the lowest concentration. Tyrosol, hydroxytyrosol, vanillic acid, p-cumaric acid, luteolin, and apigenin levels were greater in early harvested samples in almost all oils analysed. Antioxidant activity measurements (antiradical, lipid peroxide inhibition, H2O2 and NO scavenging) were also accomplished for the seven varieties in the first ripening stage.

11th Euro Fed Lipid Congress, New Strategies for a High Quality Future (27–30 October 2013, Antalya, Turkey)

11th Euro Fed Lipid Congress, New Strategies for a High Quality Future (27–30 October 2013, Antalya, Turkey)

Antioxidant capacity of the phenolic fraction and its effect on the oxidative stability of olive oil varieties grown in the southwest of Spain

The characterization of olive oils from seven representative fruit varieties (Arbequina, Carrasquena, Corniche, Manzanilla Cacerena, Morisca, Picual, and Verdial de Badajoz) from the southwest of Spain is carried out according to antioxidant capacity of the phenolic fraction and oxidative stability in different ripening stages. Antioxidant capacity is measured through the reduction of a 2,2′-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid radical cation previously oxidized with peroxidase/hydrogen peroxide. The decrease in absorbance at 730 nm at 3 min was measured. Values like Trolox Equivalents Antioxidant Capacity and oxidative stability varied from 0.6 to 2.5 mmol Trolox·kg –1 oil and 28.3 to 170.9 hours Rancimat respectively. The best positive correlation between total phenolic compounds and antioxidant capacity were in the Carrasquena and Arbequina varieties. The rest showed moderated correlations. Correlation between antioxidant capacity and oxidative stability was found in a range from 0.66 to 0.97, depending on varieties.

Sensory analysis and consumer acceptance of 140 high-quality extra virgin olive oils

Sensory analysis is a crucial tool for evaluating the quality of extra virgin olive oils. One aim of such an investigation is to verify if the sensory attributes themselves - which are strictly related to volatile and phenolic compounds - may permit the discrimination of high-quality products obtained by olives of different cultivars and/or grown in various regions. Moreover, a crucial topic is to investigate the interdependency between relevant parameters determining consumer acceptance and objective sensory characteristics evaluated by the panel test. By statistically analysing the sensory results, a grouping - but not discriminatory - effect was shown for some cultivars and some producing areas. The preference map shows that the most appreciated samples by consumers were situated in the direction of the 'ripe fruity' and 'sweet' axis and opposite to the 'bitter' and 'other attributes' (pungent, green fruity, freshly cut grass, green tomato, harmony, persistency) axis. Extra virgin olive oils produced from olives of the same cultivars and grown in the same areas shared similar sensorial attributes. Some differences in terms of expectation and interpretation of sensory characteristics of extra virgin olive oils might be present for consumers and panellists: most of the consumers appear unfamiliar with positive sensorial attributes, such as bitterness and pungency.

‘Cobrançosa’ Olive Oil and Drupe: Chemical Composition at Two Ripening Stages

AbstractThe chemical composition and organoleptic characteristics of olive oils may be influenced by genotype and some agronomic factors like olive drupe harvesting date. The aim of this work was to study the influence of olive ripening stage on chemical parameters and the organoleptic profile of fruits and oils of one of the main olive Portuguese cultivars (Cobrançosa). Six different Cobrançosa clones, which were harvested at two different ripening stages in the same olive growing area, were analyzed to evaluate phenolic compounds, ortho‐diphenols, flavonoids and antioxidant activity and were characterized in terms of sensorial parameters. These clones have also been classified according to the yield of production. The lowest values in phenolic content, ortho‐diphenols, flavonoids and antioxidant activity occurred always in the same clone (110) in both ripening stages in olive fruits and olive oil. This clone has been previously identified as low yield. Also, the results revealed significant correlations between total phenolics and antioxidant activity (R2 = 0.932, P &lt; 0.0001), between ortho‐diphenols and antioxidant activity (R2 = 0.9445, P &lt; 0.0001) and between flavonoids and antioxidant activity (R2 = 0.9263, P &lt; 0.0001) on olive oil samples. The sensorial parameters that have been affected in olive oils were herbaceous aroma and flavor, and bitter taste that increased with the ripening process.

Determination of Total Olive Oil and Cis-Trans Fatty Acids Composition of Şırnak Province Olive Genotypes at Southeastern Anatolia

Determination of Total Olive Oil and Cis-Trans Fatty Acids Composition of Sirnak Province Olive Genotypes at Southeastern Anatolia Ebru Sakar, Bekir Erol Ak; Hülya Ünver; Mensure Çelik; Hüseyin Türkoglu; Siddik Keskin Abstract Olive plants, throughout history, have formed the basis of the civilizations in the Mediterranean region and in researches; the gene center is expressed Southeastern Anatolia region as homeland of olives [1]. In recent years, willingness to live healthier and longer, countries plays a decisive role in the nutrition policy. Areas where olive trees grow is effective for obtaining good quality olive oil. Fat quantity and fat quality which obtained from olive may differ by region. Therefore, increasing the efficiency in the olive oil sector at the international level, regional characterization of Turkish olive and olive oil are important. This research was run on the olives which selected as promising as a result of the selection operation 34 types, common in the population Sirnak, and olive oil contents and fatty acid composition were determined. As a result of research in the province of Sirnak genotype total oil were determined between from 2.0 % to 8.8%. The composition of fatty acids were determined as palmitic acid from 10.34% to 20.92%, stearic acid 2.25% to 3.91% ; oleic acid 49.33 % to 67.96 %, linoleic acid 7.52% to 31.51% and linolenic acid 0.63% to 2.72 %, respectively. Full Text: PDF DOI: 10.15640/jaes.v3n4a9

Chemical, thermal and viscous characterization of high-oleic sunflower and olive pomace acid oils and derived estolides

This work deals with the chemical, thermal and viscous characterization of a variety of estolides, prepared from higholeic sunflower and olive pomace acid oils, using different acid-catalyzed synthesis protocols and reaction times. Estolides with weight-average molecular weights between 1.7 and 3.4 times higher than the original acid oils were obtained. The molecular weight of the estolides was higher when using the sulphuric acid-catalyzed method and a reaction time of 3-6 h. Estolides presented higher freezing temperatures than acid oils. In general, viscosity values are related to estolide molecular weight. Significant increments in viscosities were found in comparison with acid oils. Maximum viscosity values were obtained for estolides prepared using the sulphuric acidcatalyzed method. The largest viscosity increments in olive pomace acid oil-derived estolides were observed during the first 6 hours of reaction, due to an increase in the molecular weight; longer reaction times yielded adverse results. The temperature dependence of viscosity for all estolides studied is significantly larger than for the original acid oils.

Characterization of olive oils obtained from wild olive trees (Olea ferruginea Royle) in Pakistan

Pakistan is lacking in edible oils and large amounts of resources are being used to import these. Olea ferruginea Royle (Oleaceae), locally known as Kahu, is native to Northern part of the country, and the fruit of this tree is currently not being utilized for any useful purpose. The present study was conducted to exploit a new source of virgin olive oil (OWOT) based on chemical composition and quality parameters. The fruits from wild olive trees were collected from different locations in Pakistan (i.e. Bhara Kahu, Kotli Sattian and Dir Swat); whereas a reference sample (OCOT) of a local variety (Zaitoon II) Olea europaea L. was collected from Barani Agricultural Research Institute, Chakwal (BARIC) for comparison. The basic quality characteristics of oils such as free acidity, peroxide value, specific UV absorptions and sensory analysis demonstrated that the oils belong to the “lampante olive oil” commercial category due to low quality of processed olives. Some minor discrepancies with respect to the standard olive oil composition (linoleic acid slight exceeding 1% and traces of erucic acid and brassicasterol) were found that should be further studied to understand their etiology. Concerning minor compounds, tocopherols were found in low quantities whereas higher amounts of β-carotene and lutein were observed in OWOT compared to OCOT. Finally, OWOTs showed a relatively low quantity of hydrophilic phenols that proportionally expressed three times less antioxidant activity compared with OCOT. Careful control of fruit quality and good practices before olive milling could improve not only quality of the product, but also provide a new promising source of edible virgin oils.

Physicochemical and sensory characteristics of virgin olive oils in relation to cultivar, extraction system and storage conditions

This research was carried out to evaluate the effects of variety, extraction system and storage conditions such as packaging type and temperature variation on the quality of virgin olive oil. Several parameters were studied, namely, quality indices, polyphenols, tocopherols, volatile compounds and sensory properties. Thus, two olive varieties Chemlali (Tunisia) and Coratina (Italy) were selected. The olive oils were extracted by different industrial processes (super press, dual and triple phase decanter) then stored in the established conditions (ambient and refrigerator temperature) in the following packaging materials: clear and dark glass bottles and metal bottles. The oils were analyzed before and after being stored for 9months. Principal Component Analysis and Graphical Modeling were applied to fully explore the influence of the studied factors. Results revealed that among samples, oils from Coratina cultivar were the richest in γ-tocopherol while Chemlali oils contained the highest amount of Δ-tocopherol. Quality indices namely K232 and K270 values were mainly influenced by the storage date and packaging material. Meanwhile, free acidity and peroxide value were mainly influenced by the extraction system. Concerning tocopherols, α-tocopherol content was mainly influenced by the packaging material, β-tocopherol was mainly affected by the storage date, for γ-tocopherol content the main influencing factor was the cultivar whereas for Δ-tocopherol the main influencing factor was the extraction system. Regarding volatile compounds their amounts were influenced mainly by the storage date, that was influenced by the packaging material, where a considerable decrease was observed after storage which was reflected by the change of sensory characteristics of stored oils: loss of positive attributes fruitiness, bitterness and pungency and onset of defects which were mainly influenced by the storage date (fruity and bitter attributes), packaging material (pungent, rancid and fusty attributes) and extraction system (musty attribute).

Study and characterization of Palestinian monovarietal Nabali virgin olive oils from northern West Bank of Palestine

This work presents a preliminary evaluation of the quality of Palestinian olive cv. Nabali cultivated in different locations (Nablus, Salfit, Qalqilya, and Jenin). Several parameters have been studied, such as quality indices, fatty acid composition and minor compounds of olive oil. The majority of the studied parameters showed significant variations among virgin olive oil samples according to the production zone. Nablus oil showed the highest percentage of oleic acid, the lowest percentage of linoleic acid and was the richest in phenolic compounds. Chemometric analyses were performed in order to classify the VOOs (virgin olive oils) according to their production zone.

NMR‐based metabolomic approach for EVOO from secular olive trees of Apulia region

In this work, a first level investigation was carried out to study the extra virgin olive oils (EVOOs) obtained from secular olive trees of Apulia region. Microextracted olive oil samples from selected and genetically characterized olive trees were studied by 1H NMR‐based metabolomic approach and multivariate analysis, according to cultivar and geographic origin, within the Apulia region. The 1H NMR spectra of oils were analyzed by several pattern recognition methods, using both unsupervised (principal component analysis) and supervised (partial least squares discriminant analysis, orthogonal partial least squares discriminant analysis (OPLS‐DA)) statistical techniques. EVOOs obtained from secular olive trees could be easily differentiated by OPLS‐DA not only depending on the used cultivars but also according to their geographical origin within the different districts of the Apulia region, such to justify a larger biodiversity maintenance of Apulia secular germplasm. Therefore, differences in chemical composition and NMR profiles of EVOOs may be explained either by cultivars or geographic areas.Practical applications: About 10% of the genetic olive tree patrimony within the Apulia region consists of the secular olive trees. A recently introduced regional law (No 14 of June 4th, 2007) allows to exploit oil produced from secular olive trees by labeling it with the special mention: “extra virgin oil from the Apulia secular olive trees”. Characterization of extra virgin olive oils obtained from secular trees may be an optimal solution to increase the value for this product and make it available on the market. On the other hand this economic issue is very important to preserve the unique landscape offered by the ancient olive groves of the Apulia region in south east Italy.

Development of a Prototype for Extra-Virgin Olive Oil Storage with Online Control of Injected Nitrogen

<abstract> <bold><sc>Abstract.</sc></bold> The conservation of oil is a very complex operation because, to maintain the quality level over time, it is necessary to take precautions to avoid increased acidity and the onset of rancidity caused by oxidation, as well as problems related to the anaerobic fermentation of suspended matter in the oil or deposited on the bottom of the storage vessels. This article describes the development of a prototype integrated olive oil storage system. The storage system consists of a nitrogen gas generator, three stainless steel tanks, and a feedback controller for nitrogen concentration and tank temperature. In the first experiment, three tanks were used to test the functionality of the system. The experimental design was based on the creation of a different modified atmosphere in the headspace of each tank using the nitrogen gas generator and feedback controller. In the second experiment, four tanks were used to validate the functionality of the prototype system using a different type of extra-virgin olive oil. The results of this research show that the prototype performed well in terms of its ability to detect and adjust the atmosphere of the tank headspace. In the first experiment, the oxygen percentage in the headspace of the three tanks remained between 0.7% and 0.9%. Chemical analyses of acidity, total phenol content, and peroxide index showed that the controlled headspace made it possible to maintain acidity levels within the range of 0.30% to 0.37%, total phenol content in the range of 247 to 252 ppm (gallic acid equivalent), and peroxide index values in the range of 8.80 to 9.70 meq O₂ per kg of oil during the experiment. The proposed prototype provided effective control and regulation of the oxygen concentration in the headspace of the tanks and can help maintain the chemical characteristics of extra-virgin olive oil over time. The second experiment confirmed that the prototype storage system was able to maintain the chemical characteristics of the stored extra-virgin olive oil.

Mass spectrometry to evaluate the effect of the ripening process on phenols of virgin olive oils

SummaryA global approach has been developed to study the influence of ripening of olive fruits on the phenolic fraction present in virgin olive oil from different genotypes of olives. For this purpose, a non‐targeted method based on the analysis of phenolic extracts by MS in high resolution mode was applied. The phenolic profiles obtained by liquid chromatography ‐ quadrupole‐quadrupole‐time‐of‐flight (LC‐QqTOF) were compared by statistical multivariate analysis tools such as principal component analysis and heat correlation maps. In overall terms, discrimination was only observed for specific crop dates and ripening index values, which should be ascribed to a strong influence of the genotype. The ripening process of each genotype was also studied to demonstrate the variation of phenolic profile in relation to the ripening index. This study was also extended to a panel of representative phenols appreciated by their health and nutritional properties. The application of omics technologies to plant breeding programs could be considered as one of the main pillars on which improvement of products quality can be supported.Practical applications: Olive oil phenols are of a great interest since they contribute to autoxidation stability, health properties, and organoleptic characteristics of virgin olive oil. These phenols are considered a key to assess virgin olive oil quality. This study is focused on the effect of the ripening process on the phenolic fraction from a metabolomics point of view. This advanced omics technology (foodomics) applied to plant breeding programs can be one of the pillars to improve products quality.

High Pressure Rheology of Environmentally Friendly Vegetable Oils

Environment-friendly lubricant is the key demand in twenty-first century for the issue of global climate change. Vegetable oils as base oil for lubricants and biodiesel fuel are environmentally preferable to petroleum. They are usually excellent boundary lubricants, but their high-pressure behavior is not investigated yet properly. In this research, first solidification characteristics of rapeseed oil, soybean oil, sunflower oil, palm oil, coconut oil, olive oil, camellia oil, mustard oil, castor oil, rapeseed methylester, and soybean methylester were investigated. Next, a very useful viscosity–pressure–temperature relation on the basis of phase diagram was derived for the nine vegetable oil.