Evaluation of potential and real quality of virgin olive oil from the designation of origin “Aceite Campo de Montiel” (Ciudad Real,Spain)

The potential and real qualities of virgin olive oils from the DO “Aceite Campo de Montiel” were evaluated. The regulated physicochemical and sensory parameters, the stability parameters and the fatty acid, sterol and triterpenic dialcohol compositions were analysed. The results of the regulated parameters in the potential quality study classified all the analysed oils into the “extra virgin” category. The varieties Picual and Cornicabra showed remarkably high stability, due to their high tocopherol and total polyphenol contents. Oleic and linoleic acids were the most useful fatty acids used to discriminate the predominant varieties, Picual and Cornicabra, from the others. The variety Cornicabra stood out due to its high campesterol content, Arbequina due to its low β-sitosterol content and high 24-methylenecholesterol, Δ5-avenasterol, Δ7-stigmastenol and total sterol contents, and Picual for its high sitostanol content. All the analysed samples in the real quality study were classified in the “extra virgin” category according to the regulated physicochemical parameters, but only 69% of them qualified if the sensory parameters were also taken into account. The predominance of the varieties Picual and Cornicabra in the study area was mainly responsible for the high oil stability and reflects the fatty acid and sterol compositions of the oils from the oil mills in the potential quality study.     

Effect of oxygen reduction during malaxation on the quality of extra virgin olive oil (Cv. Carboncella) extracted through “two-phase” and “three-phase” centrifugal decanters

Quality and composition of virgin olive oil (VOO) are strictly dependent on complex processes that take place during the olive fruit crushing and malaxation of the olive paste. In this work, modulation of O₂ levels within malaxation chambers (R1: unmodified atmosphere; R2: oxygen: 12.73–4.64 kPa from the beginning to the end of malaxation; R3: 10.46–2.27 kPa; R4: 9.87–0.69 kPa) in two continuous “two-phase” and “three-phase” oil extraction plants was performed. Combined effects on the biosynthesis of nutritionally bioactive molecules and aroma volatiles and on the resulting sensory properties of the produced oils were investigated. Results showed that the type of oil extraction plant markedly affected the level of the phenolic compounds in the oil (and the related sensory attributes of bitter, pungency, astringency and bitter and pungency persistence). Reduction of O₂ concentration in the malaxing chamber, while having a minor impact on the presence of phenolic compounds, significantly affected the formation of all the examined volatiles. Particularly, lowered levels of oxygen hindered the formation of lipoxygenase derived volatiles weakening odours and flavours of artichoke, fresh fruity, and fresh cut grass.     

The effects of genotype and extraction methods on chemical composition of virgin olive oils from Traslasierra Valley (Córdoba,Argentina)

This work was carried out to assess the influence of two extration methods (two-phase centrifugation and pressure) on oil quality from four olive varieties cultivated at Traslasierra Valley, Córdoba, Argentina. Analysis of the effect of the extraction system, on the values of analytical determinations, revealed statistically significant differences in some parameters, mainly in free fatty acid and phenol contents, and K₂₇₀ values. Oxidative stability showed a significant positive correlation with phenol content. Most of the quality indices and fatty acid compositions showed significant variations among olive varieties. Nevadillo variety had the highest values of oleic acid, whereas Manzanilla was noteworthy for its higher content of phenolic compounds. Accordingly, pressure-extracted oil from the Manzanilla variety presented better oxidative stability.     

陇南两种单品种初榨橄榄油的化学性质和脂肪酸组成随成熟度的变化

分析了陇南2个品种初榨橄榄油的化学性质和脂肪酸组成随成熟度增加的变化规律。结果表明：随着成熟度的增加2个品种的鲜果出油率增加且存在显著性差异。初榨橄榄油风味成分中氮氧化合物、含硫以及烷烃类化合物变化幅度较大,通过电子鼻可以区分不同品种不同成熟度的橄榄油。恩帕特雷和科拉蒂的k232、270值最高分别为1.85和1.91、0.18和0.14,多酚、黄酮含量变化范围分别为2.39～4.53和7.47～10.39、0.07～0.40和0.75～2.84 mg/g。氧化稳定时间在第6（6.28 h）和第5(16.71 h)成熟度为最高。酸价的变化范围分别为0.37～1.02和0.19～0.38 mg/g,过氧化值的变化范围分别为2.92～8.32和2.38～5.19 mmol /kg,油酸含量分别为72.36%～77.76%和59.23%～65.73%,亚油酸含量分别为7.70%～11.81%和9.74%～15.86%,SFA含量分别为11.81%～13.15%和14.25%～20.99%,PUFA含量分别为8.34%～12.36%和10.92%～16.84%,MUFA含量为72.69%～78.50%和62.36%～68.20 %。同一品种的MUFA/PUFA、C18:1/C18:2和MUFA含量变化趋势一致,与PUFA呈相反的变化趋势,2个品种之间各种脂肪酸含量差异明显,上述测定指标完全符合GB 23347—2009中特级初榨橄榄油的标准。科拉蒂的出油率、多酚、黄酮、油酸含量和氧化稳定时间明显大于恩帕特雷,而酸价、过氧化值低于后者。综合考虑认为科拉蒂的初榨橄榄油品质优于恩帕特雷,恩帕特雷和科拉蒂分别在第6和第5成熟度的初榨橄榄油品质最好。     

Instrumental and multivariate statistical analyses for the characterisation of the geographical origin of Apulian virgin olive oils

In this paper, virgin olive oils (VOOs) coming from three different geographic origins of Apulia, were analysed for free acidity, peroxide value, spectrophotometric indexes, chlorophyll content, sterol, fatty acid, and triacylglycerol compositions. In order to predict the geographical origin of VOOs, different multivariate approaches were applied. By performing principal component analysis (PCA) a modest natural grouping of the VOOs was observed on the basis of their origin, and consequently three supervised techniques, i.e., general discriminant analysis (GDA), partial least squares-discriminant analysis (PLS-DA) and soft independent modelling of class analogy (SIMCA) were used and the results were compared. In particular, the best prediction ability was produced by applying GDA (average prediction ability of 82.5%), even if interesting results were obtained also by applying the other two classification techniques, i.e., 77.2% and 75.5% for PLS-DA and SIMCA, respectively.     

Sterolic composition of Chétoui virgin olive oil: Influence of geographical origin

The sterol profile of Tunisian virgin olive oils produced from Chétoui cultivar, the second main variety cultivated in the north of the country, grown under different environmental conditions, was established by gas chromatography using a flame ionisation detector. More than ten compounds were identified and characterised. As expected for virgin olive oil, the main sterols found in all Chétoui olive oils were β-sitosterol, Δ5-avenasterol, campesterol and stigmasterol. Cholesterol, 24-methylenecholesterol, clerosterol, campestanol, sitostanol, Δ7-stigmastenol, Δ5,24-stigmastadienol, and Δ7-avenasterol were also found in all samples, but in lower amounts. Most of these compounds are significantly affected by the geographical origin. The majority of the Chétoui virgin olive oils analysed respected EC Regulation No. 2568, and in all cases total sterol amounts were higher than the minimum limit set by legislation, ranging from 1017 to 1522 mg/kg.     

Influence of filtration on volatile compounds and sensory profile of virgin olive oils

The influence of filtration through a hydrophilic cotton layer on volatile compounds, sensory characteristics and colour of two monovarietal oils was investigated in this study. Volatiles were evaluated using headspace solid-phase microextraction-gas chromatography. After the filtration of Bu?a oils only a slight increase in total alcohols was noticed. In filtered ?rna oils a significant decrease of total alcohols and slight changes in total aldehydes, total ketones and total C5 volatile compounds concentration were detected. No significant influence on the sensory scores of oils, but some slight changes in sensorial profiles were noted (slightly higher intensities of sensory characteristics apple and grass, and higher values of the lightness L^∗ in filtered samples). The results point to unequal filtration impact on different monovarietal oils and could be useful in developing targeted technologies for specific monovarietal oils quality improvement.     

Characterisation of the geographical origin of Western Greek virgin olive oils based on instrumental and multivariate statistical analysis

In this work, measurements of free acidity, peroxide content, spectrophotometric parameters, chlorophyll content, phenol, sterol, fatty acid and triacylglycerol composition, were carried out on samples of virgin olive oils (VOOs) coming from four different Greek Ionian islands, i.e. Zakynthos, Kefalonia, Lefkada and Kerkyra. An analysis of variance (ANOVA) highlighted statistically significant differences (p < 0.01) in the values of 26 analytical parameters amongst the VOOs produced in the four different geographical regions but a post-hoc test showed that no variable was able to distinguish all four origins. Analogously, a Principal Component Analysis (PCA) showed a modest grouping of VOOs according to geographical origin except for Kerkyra samples which were more distinct from others. Applying discriminant function analysis (DFA) a good separation of the four geographical groups was achieved with classification and prediction abilities equal to 97.7% and 95.3%, respectively. Moreover, the analysis of the standardised coefficients showed that the fatty acids and triacylglycerols were the most discriminant variables. This last outcome was confirmed by comparison of the prediction performances obtained applying DFA on four subdatasets containing fatty acids (69.8%), triacylglycerols (76.7%), sterols (62.8%), and remaining parameters (65.1%) together, respectively. As the results showed, the multidisciplinary approach that combines different types of analytical determinations improved the discrimination of geographical origin for Greek virgin olive oils.     

Phenolic compounds in olive oil and olive pomace from Cilento (Campania,Italy) and their antioxidant activity

Virgin olive oil (VOO) has nutritional and sensory characteristics that make it unique and a basic component of the Mediterranean diet. Its importance is mainly attributed to its richness in polyphenols, which act as natural antioxidants and may contribute to the prevention of several human diseases. In this paper we report the determination and quantification of oleocanthal, one of the main substances responsible for the bitter taste of olive oil, together with a quali-quantitative analysis by HPLC analytical methods of phenolics from Cilento VOO and olive oil pomace. The total phenolic content was also determined and the in vitro antioxidant and free-radical scavenging activities by DPPH test was evaluated. A superoxide anion enzymatic assay was also carried out and the results were confirmed by the inhibition of xanthine oxidase activity assay. The possible protective role played by VOO secoiridoids on injurious effects of reactive oxygen metabolites on the intestinal epithelium, using Caco-2 human cell line, was investigated.     

Evolution of major and minor components and oxidation indices of virgin olive oil during 21 months storage at room temperature

This article reports the evolution of major and minor components and oxidation indices of seven samples of virgin olive oil (VOO) which differ in their initial contents of natural antioxidants, during 21 months of storage at room temperature and in darkness. As expected, statistically significant differences in the antioxidant contents were observed, with initial concentrations ranging from 0.33 to 0.55 mmol/kg for α-tocopherol and from 1.08 to 3.88 mmol/kg for total phenols. The quality indices PV, K₂₃₂ and K₂₇₀ increased linearly during the storage time studied (21 months), which should make it possible to predict the shelf-life of a VOO sample by extrapolation from the results obtained during a relatively short period of storage (i.e. several weeks). K₂₃₂ was the first parameter that exceeded the established upper limit for extra VOO and therefore seems to be the most relevant index for analysis and monitoring to determine the commercial category of the olive oil. The reduction of total phenolic compounds ranged from 43% to 73%, and it was remarkable that the decrease was higher in samples whose initial phenol contents were greater. Hydroxytyrosol increased linearly in most samples, whereas its complex forms decreased considerably, with the exception of two in which the hydroxytyrosol content decreased continuously or diminished after an initial increase. This fact was probably due to the low initial concentration of hydroxytyrosol secoiridoid forms: i.e. 0.32 mmol/kg for the sum of 3,4-DHPEA-EDA and 3,4-DHPEA-EA in one of these samples as compared to between 0.65 and 2.06 mmol/kg in the others. Finally, there was a slight and apparently linear fall in the α-tocopherol content of all samples, with a reduction ranging from 0.054 mmol/kg (12%) to 0.127 mmol/kg (23%), although there may be a short lag phase at the beginning of the assay.     

Looking through the qualities of a fluorimetric assay for the total phenol content estimation in virgin olive oil,olive fruit or leaf polar extract

As an alternate to the Folin-Ciocalteu assay (F-C) we propose a fluorimetric estimation of the total phenol content in virgin olive oil (VOO), olive fruit and leaf polar extracts. Phenol content was determined at excitation/emission wavelengths set at 280/320 nm. Standard operational procedures (slit widths, temperature, pH) and method validation were carried out according to Eurachem guidelines. The qualities of the proposed assay are better than those of the F-C one, as the procedure is more sensitive (LOD and LOQ values 10-fold lower), three times faster, needs no reagents and most importantly, is not destructive for the sample that can be further used in HPLC or other assays. Data for VOO extracts correlated well with the colorimetric ones (r = 0.69, n = 65). HPLC coupled with diode array and fluorescence detectors supported the above findings. Good correlations were also found between the respective data for olive fruit and leaf extracts (r = 0.96, n = 18).     

Advance technology in virgin olive oil production from traditional and de-stoned pastes: Influence of the introduction of a heat exchanger on oil quality

An experimental investigation was carried out to evaluate the quality of virgin olive oils obtained when a de-stoner were used for the olive paste preparation in comparison to the use of a traditional stone mill. In order to improve the slightly differences of oil yields due to the use of the de-stoner also a heat exchanger has been introduced in the processing line. The experimental data showed that resistance to the oxidation, total phenols and pleasant volatile compounds were higher in the de-stoned olive oils than in the oils obtained from the whole paste. Resistance to oxidation was assessed by Rancimat method and showed a positive correlation with the amount of total phenols.     

Virgin olive oil (VOO) production in Tunisia: The commercial potential of the major olive varieties from the arid Tataouine zone

The commercial potential of olive oils from three consecutive crop years, derived from the main autochthonous olive varieties Chemlali Tataouine, Fakhari Douirat, Zarrazi Douirat and Dhokar Douirat grown in the arid region of Tataounine (Tunisia) was examined with regards to stability and nutrition aspects. Several characteristics such as fatty acid composition, the extremely high phenol-type antioxidant content, and the low levels of green pigments suggested that these oils, the only fat source for the local people, are of promising composition. Efforts to develop commercial products from these varieties could improve antioxidant intake of the local population. The introduction of Good Manufacturing Practices is a prerequisite so that the quality observed for oils obtained by an Abencor system to be achieved also in real life. This can be feasible through appropriate oleoculture, which is often the only viable agricultural activity in remote arid regions such as Tataouine.     

西班牙和意大利进口特级初榨橄榄油品质比较

为了系统研究我国主要进口的特级初榨橄榄油性质,比较分析了我国主要进口的8种西班牙和意大利特级初榨橄榄油的脂肪酸组成、酸值、过氧化值及微量成分含量,并对其进行了挥发性成分分析及感官评价。结果表明：西班牙特级初榨橄榄油的C18∶1（77.22%）和C23∶0（0.94%）含量平均值高于意大利样品（分别为72.46%和0.64%）,西班牙特级初榨橄榄油的酸值、过氧化值低于意大利样品;西班牙特级初榨橄榄油中含有γ-生育酚和δ-生育三烯酚,而意大利样品中未检出这两种,且西班牙特级初榨橄榄油中α-生育酚含量平均值（189.58 mg/kg）高于意大利样品（161.26 mg/kg）,角鲨烯含量平均值（6 127.83 mg/kg）远高于意大利样品（4 083.50 mg/kg）,两者甾醇含量差异很小。虽然西班牙特级初榨橄榄油的醛类含量平均值低于意大利样品,但酯类含量更高。感官评价发现,西班牙特级初榨橄榄油的果味、苦味、辣味评分皆高于意大利样品。综上,西班牙特级初榨橄榄油的酸值、过氧化值较低,α-生育酚、角鲨烯含量高于意大利样品,且感官评分较高。     

Estimation of the intake of phenol compounds from virgin olive oil of a population from southern Spain

The objective of the study was to determine the mean polyphenol composition of different varieties of virgin olive oil (VOO) habitually consumed in the region of southern Spain and to estimate the dietary exposure to olive oil polyphenols in that population. There were statistically significant differences in total polyphenols among varieties, with the Picual variety containing the largest amount with a mean value of 591.8 mg kg^–1. The main phenolic compounds found in the VOOs under study were tyrosol and hydroxytyrosol. The highest amounts of both substances were found in Picual olive oils with concentrations of 2.3–6.6 mg kg^?1. The total intake of polyphenols from VOO ranged between 8.2 mg day^–1 (SD = 4.14) for the under 19 year olds and 21.3 mg day^–1 (SD = 3) for the over 50 year olds. Some polyphenols, including tyrosol and hydroxytyrosol, were consumed principally as olive oil. The intake of these compounds in the studied population was in the range of 88.5–237.4 μg day^–1. This has particular importance as recent studies have demonstrated that hydroxytyrosol helps to improve plasma lipids levels and repair oxidative damage related to cardiovascular disease. There was a greater dietary consumption of polyphenols in olive oil among the participants who more closely followed the Mediterranean diet pattern. A higher consumption of olive oil and therefore a greater exposure to polyphenols was observed in females versus males and in participants of normal weight versus those who were overweight. The total intake of polyphenols from VOO significantly increased with higher age, reflecting the greater intake of this oil by older people, who also show a closer adherence to the Mediterranean diet. The over 50-year-old age group showed the greatest consumption of this olive oil and therefore of phenolic compounds, which are healthy protectors in the human diet that contribute to the acknowledged benefits of the Mediterranean diet.     

Wax ester composition of monovarietal olive oils from Designation of Origin (DO) “Campos de Hellin”

The wax ester composition of six monovarietal olive oils (Arbequina, Benizal, Cornicabra, Cuquillo, Manzanilla, and Picual) from Designation of Origin (DO) “Campos de Hellin” (Spain) were analysed, to obtain a more complete characterisation of these varietal oils. The analyses were carried out by on-line liquid chromatography–gas chromatography (LC–GC) using the Through Oven Transfer Adsorption Desorption (TOTAD) interface. The oil made with Arbequina variety had the highest content of total wax ester (84.4 ± 4.3 mg/kg) and Picual oil the lowest (35.5 ± 3.7 mg/kg). The data obtained were analysed statistically; significant differences in C40, C44, C46 and total wax esters were found, with a level of confidence of 95%.     

Effects of olive paste fast preheating on the quality of extra virgin olive oil during storage

The olive paste obtained after crushing was fast preheated under different time/temperature conditions and then malaxed in an industrial oil mill (600 kg Frantoio/Leccino olive blend). Legal parameters (peroxides, free acidity and sensory panel), oil yield, total phenolic content, oxidative stability and phenolic profile were monitored during 12 months of storage of the virgin olive oil (VOO) kept in closed bottles in the dark. A fast preheating not longer than 72 s at 38 °C without malaxation lead to an extra VOO with a shelf-life of at least 12-months, similarly to the traditional EVOO obtained with malaxation. A fast preheating not longer than 72 s at 38 °C followed by 10 min malaxation lead to an EVOO with a ‘mild’ sensory profile and a shelf life of at least 12-months. Thus, the use of a specific designed fast preheater instead or before (a shortened) malaxation allows to obtain an EVOO with a low bitter/pungent attribute from olives which are rich of (sometimes unpleasant) phenolic compounds with the aim to meet the preference of targeted groups of consumers. Time and temperature of fast preheating are the critical parameters of the process.