Search

Copyright of Revista Foco (Interdisciplinary Studies Journal) is the property of Revista Foco and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Food & Fermentation Industries is the property of Food & Fermentation Industries and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Despite the importance of the insight about the oxidation mechanisms (i.e., radical and singlet oxygen (1O2) oxidation) in extra virgin olive oil (EVOO), the elucidation has been difficult due to its various triacylglycerol molecular species and complex matrix. This study tried to evaluate the mechanisms responsible for EVOO oxidation in our daily use by quantitative determination of triacylglycerol hydroperoxide (TGOOH) isomers using LC-MS/MS. The standards of dioleoyl-(hydroperoxy octadecadienoyl)-triacylglycerol and dioleoyl-(hydroperoxy octadecamonoenoyl)-triacylglycerol, which are the predominant TGOOHs contained in EVOO, were prepared. Subsequently, fresh, thermal-, and photo-oxidized EVOO were analyzed. The obtained results mostly agreed with the previously reported characteristics of the radical and 1O2 oxidation of linoleic acid and oleic acid. This suggests that the methods described in this paper should be valuable in understanding how different factors that determine the quality of EVOO (e.g., olive species, cultivation area, cultivation timing, and extraction methods) contribute to its oxidative stability. [ABSTRACT FROM AUTHOR]

Extra virgin olive oil is widely consumed because of its nutritional benefits and sensory properties which are very important to be preserved in the product. Therefore, chemically synthesised compounds, such as butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT), are widely used as antioxidants in oil products. It is well known that the activity of some micro-organisms able to oxidise free fatty acids can lead to the loss of the stability of the final product. Nevertheless, several researchers have been recently motivated to evaluate the potential of micro-organisms on the production of bioactive compounds. In this paper, headspace solid micro-extraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS) were used for the characterization and investigation of Fungal Organic Volatile Metabolites (FOVCs) emitted by 14 fungal strains isolated from olives during their pre-processing storage. A wide range of volatile compounds were detected among them, BHT was produced at levels ranging between 0.3 and 13.1%. This compound could be considered for the industry as natural antioxidant to substitute the synthetic ones used for ameliorating the stability of olive oil and other fatty food products. Practical applications: As the pre-processing storage step is inevitable for several practical reasons, inducing the outgrowth of olive microflora (mainly fungi), which critically affect the physiological state of the fruit and thus the quality of the correspondent oil, this paper try to elucidate the potential of these naturally developing strains and their metabolites (FVOCs) of producing bioactive compounds mainly the BHT which could be considered by the industry in order to substitute the synthetic one largely used to improve the stability of olive oil and other food products. Volatiles, when coupled with the power 'omics' technologies represent a new frontier in bio-prospecting. FOVCs profile of 14 fungi strains isolated from olives stored during 2, 5, and 7 days in plastic bags is determinate by HS-SPME-GC-MS. 87 FVOCs are detected representing six groups dominated by the non-terpene derivatives. Interestingly, a compound with particular interest is detected; the Butylated Hydroxytoluene (BHT) is naturally emitted by 11 strains from the 14 isolated fungi at levels ranging between 0.3 and 13.1% (for Aspergillus conicus). A result which could be considered by the industry in order to substitute the synthetic antioxidants largely used to improve the stability of olive oil and other food products. [ABSTRACT FROM AUTHOR]

Spices and herbs are traditionally added to olive oil in Mediterranean gastronomy to enhance its aroma and taste. This paper aims to characterize olive oil aromatized by addition of dried chili pepper ( Capsicum annum) (DCP) at different concentrations (10% and 20% by weight) up to 30 days of infusion. Capsaicinoids quantification by HPLC-DAD, volatile compounds analysis by SPME-GC-MS and antioxidant activity by ABTS method were performed on chili pepper flavored olive oil (CPOO) in comparison to whole olive oil. At day 7 of infusion, the maximum capsaicinoids content was reached for both the concentrations used and no significant increase was observed for longer infusion times. The volatile headspace composition of CPOOs was influenced by the concentration of DCP added. The addition of DCP caused a significant increase in hexanal, related to oxidation processes. 2-Methylbutanal, 3-methylbutanal and 6-methyl-5-hepten-2-one were also detected in CPOO and derived from chili as degradation products of the drying process. DCP infusion significantly enriched olive oil with antioxidant compounds and also modified its volatile profile. Capsaicinoids and aroma compounds were rapidly released within the first week of chili infusion in CPOOs, thus suggesting reducing infusion time by optimizing DCP concentration in order to improve CPOO quality and shelf life. Practical applications: The present research is relevant at industrial level for the optimization of olive oil flavoring and the aromatization process. In particular, we defined that the common infusion times of chili, used at industry production for flavoring olive oil, is longer than needed and we suggest reducing infusion time thus also avoiding problems of free acidity and PV increase. Also, we highlighted the importance of quality control for the chili pepper drying procedure and storage time before use, due to the possible formation of off-flavors in the final product. Moreover, in the present paper a quantification method of the pungent molecules capsaicin and dihydrocapsaicin directly from flavored olive oil was applied. This method could be applied instead of empirical techniques such as Scoville units, for the definition and standardization of the capsaicinoids content in flavored oils and their pungency levels. [ABSTRACT FROM AUTHOR]

This work systematically investigates the oxidation of extra virgin olive oil (EVOO) under accelerated storage conditions with UV absorption and total fluorescence spectroscopy. With the large amount of data collected, it proposes a method to monitor the oil's quality based on machine learning (ML) applied to highly-aggregated data. EVOO is a high-quality vegetable oil that has earned worldwide reputation for its numerous health benefits and excellent taste. Despite its outstanding quality, EVOO degrades over time due to oxidation, which can affect both its health qualities and flavour. Therefore, it is highly relevant to quantify the effects of oxidation on EVOO and develop methods to assess it that can be easily implemented under field conditions, rather than in specialized analytical laboratories. The ML approach indicates that the two excitation wavelengths (480 nm) and (300 nm) exhibit the maximum relative change in fluorescence intensity during the ageing for the majority of the oils, thus identifying the wavelengths which are more informative for quality prediction. Also, the paper proposes a method for the prediction of olive oil quality using highly-aggregated data. Such a method is of interest because it paves the way to the realization of a low-cost, portable device for in-field quality control. The following study demonstrates that fluorescence spectroscopy has the capability to monitor the effect of oxidation and assess the quality of EVOO, even when the data are highly aggregated. It shows that complex laboratory equipment is not necessary to exploit fluorescence spectroscopy using the proposed method and that cost-effective solutions, which can be used in-field by non-scientists, could provide an easily-accessible assessment of the quality of EVOO. • Extensive UV-absorption spectroscopy analysis reveals insights into EVOO's oxidation processes. • Total fluorescence spectroscopy analysis explores fluorescence characteristics of EVOOs during ageing. • Determination of specific excitation wavelengths that are highly informative for assessing EVOO quality. • Machine learning algorithms achieve accurate classification of EVOOs as extra virgin or non-extra virgin. • Proposed method using aggregated data enables low-cost and portable EVOO quality assessment. [ABSTRACT FROM AUTHOR]

Background: According to Neapolitan Pizza Traditional Specialty Guaranteed (TSG) regulation, Mozzarella di Bufala Campana and Fiordilatte mozzarella are the exclusive cheeses to be used, together with tomato and extra virgin olive oil (EVOO), to season pizza in the "Margherita" variant. However, the so-called "Pizza mozzarella", that is a diary product having lower moisture content and a longer shelf life than Mozzarella di Bufala Campana and Fiordilatte mozzarella, is widely used in many pizzerias, both in Italy and abroad. Therefore, we investigated its quality, in comparison with Mozzarella di Bufala and Fiordilatte mozzarella, as well as its effect on the quality of the Margherita pizza. Methods: Chemical and sensory analyses were conducted on mozzarella samples and on baked pizza topping samples. Results: The results revealed a better quality of pizza with Mozzarella di Bufala and Fiordilatte mozzarella for their higher antioxidant activity, oxidative stability and lower amount of undesired volatile compounds. Conclusions: The use of Mozzarella di Bufala and Fiordilatte mozzarella in the preparation of Margherita pizza improves its quality, especially if these mozzarella types are combined with other high-quality ingredients, namely tomato sauce and EVOO, characterized by the presence of antioxidant compounds (e.g., α-tocopherol not affected by the heat treatment of pizza baking. [ABSTRACT FROM AUTHOR]

Purpose – This paper aims to evaluate effects of the fortification of polyphenolic compound mixtures of quercetin, caffeic acid, tryrosol and hydroxytyrosol in olive oil oxidation. Design/methodology/approach – The authors measured olive oxidation initiated by copper using thiobarbituric acid reactive substance, as an indicator of lipid peroxidation. Findings – Overall, most mixture combinations exhibited oxidation similar to olive oil alone. Some mixture combinations of polyphenolic compounds acted as antioxidants; however, as the concentrations were changed, they became prooxidant in nature. Research limitations/implications – In vitro studies have limitations for extrapolation to in vivo and clinical studies. Practical implications – Such information will be useful in determining optimal concentrations and combinations of antioxidants for reducing rancidity and perhaps as models that could be used to modulate various chronic diseases that are associated with oxidative stress. Originality/value – Olive oil, along with fruits, vegetables and fish, are important constituents of health promoting diets, such as the Mediterranean diet. Active ingredients include monounsaturated fatty acids, oleic acid and a variety of antioxidants including various polyphenolic compounds. [ABSTRACT FROM AUTHOR]

The present paper reports on the changes in the volatile composition of virgin olive oils (VOO) stored for 18 months. VOO samples of five Greek olive varieties were stored in dark glass bottles (headspace 0.5%) in a basement without central heating. Even after 18 months of storage, the basic quality characteristics of the samples, such as free acidity, K232, K270, and peroxide values, did not exceed the upper limits set by European Community Regulations for VOO. Regarding the lipoxygenase pathway products, responsible for the positive sensory notes, it was shown that their total amount remained stable during the storage period. Even though the physicochemical characteristics did not exceed the upper limits, high rates of formation of volatile oxidation products, which are responsible for the off-flavors, were observed. Among the volatile oxidation products, the highest rates of formation were monitored for heptanal, 2-heptenal, and pentanal followed by hexanal and nonanal. The formation rate of volatile oxidation products was higher in VOO from Lianolia and Asprolia compared to VOO from Koroneiki, Native from Zakynthos and Thiaki varieties. Finally, stepwise linear regression analysis (SLRA) selected linoleic acid and total phenol/ ortho-diphenols ratio as having the maximum correlation with the formation rate of 2-heptenal. Practical applications: This research reports on the changes in the quality characteristics of VOO, stored for 18 months, of the main olive varieties cultivated in the western Greece. Furthermore, it provides information on the changes in volatile composition, which is responsible for positive and negative flavor attributes. Results from this study may contribute to a better understanding of the relationships between minor and/or major components and the autoxidation process. Moreover, results could be useful to VOO packagers and marketers in order to estimate the shelf-life of individual varieties. VOO from Koroneiki, Native from Zakynthos and Thiaki varieties, which are characterized by low linoleic acid contents, can be preserved for a longer period compared to VOO from Lianolia and Asprolia varieties, which are characterized by high linoleic acid contents. During storage of virgin olive oil (VOO) for 18 months, lipoxygenase pathway products, responsible for the positive sensory notes, remained stable. Among the volatile oxidation products, the highest rates of formation were monitored for heptanal, 2-heptenal, and pentanal, followed by hexanal and nonanal. 2-heptenal was correlated with VOO unsaturation and has been suggested as oxidation marker during storage. [ABSTRACT FROM AUTHOR]

Samples of edible oils of different degrees of unsaturation were studied by Raman spectroscopy. We demonstrate the potential of this technique for discriminating these oils. In addition, the Raman spectra for the macadamia, pecan, and Brazil nut oils are for the first time reported here. The fatty acid profile of each type of oil was established by GC. The analytical results obtained from the spectra were highly correlated with those provided by GC as regards the contents in monounsaturated andPUFA of each oil type. Spectra were examined separately in the wave number zones 2800-3100 and 800-1800 cm-1, which were those exhibiting the greater differences between oils. Also, as shown in this work, Raman spectroscopy is an effective tool for assessing oxidation in various grades of olive oils. Based on the results, extra virgin olive oil efficiently resists oxidation in the short term by virtue of its increased antioxidant contents. Practical applications: In this paper we show the usefulness of Raman spectroscopy to distinguish between edible oils. Similarly, the technique also allows us to discriminate between different heat-treated olive oils. At the industrial level Raman spectroscopy can be a useful tool to detect adulteration related to the oxidation of fat. Its ease of use and the absence of sample handling make it very effective for use in production systems on-line. [ABSTRACT FROM AUTHOR]

This paper reviews some catalytic wet air oxidation (CWAO) investigations of industrial wastewaters over platinum and ruthenium catalysts supported on TiO2 and ZrO2 formulated to be active and resistant to leaching, with particular focus on the stability of the catalyst. Catalyst recycling experiments were performed in batch reactors and long-term stability tests were conducted in trickle-bed reactors. The catalyst did not leach upon treatment of Kraft bleaching plant and olive oil mill effluents, and could be either recycled or used for long periods of time in continuous reactors. Conversely, these catalysts were rapidly leached when used to treat effluents from the production of polymeric membranes containing N,N-dimethylformamide. The intermediate formation of amines, such as dimethylamine and methylamine with a high complexing capacity for the metal, was shown to be responsible for the metal leaching. These heterogeneous catalysts also deactivated upon CWAO of sewage sludges due to the adsorption of the solid organic matter. Pre-sonication of the sludge to disintegrate the flocs and improve solubility was inefficient. [ABSTRACT FROM AUTHOR]

The Mediterranean region is the largest olive oil producer in the world, consequently in this area olive oil mill wastewaters have a high seasonal pollution potential. Due to the presence of phytotoxic compounds, such as poly-phenols, the olive oil mill wastewater is not easily biodegradable, and, therefore, the direct biological treatment is not recommended. Many techniques have been proposed for the their treatment, such as catalytic wet oxidation, ozonization, photo-catalysis, etc., among which, the catalytic oxidation seems to give good results. The present paper reports the results of an experimental investigation carried out with the aim to define a new catalytic oxidation process with hydrogen peroxide using copper-based catalyst, able to reduce the phytotoxicity of olive oil mill wastewaters and to recover the catalyst after oxidation treatment. The experimental results have showed that, operating in a slurry type reactor at mild operating conditions, it is possible to reduce the organic chemical oxygen demand down to 10% and the polyphenols amount of wastewater down to 1%. Therefore, the process is able to increase the rapidly biodegradable substrate content up to 80%, to remove color and total suspend solid amount and to minimize the metal loss of the catalyst after oxidation process, with a recover of about 80% with respect to its initial amount, permitting to reuse it for a long life cycle. [ABSTRACT FROM AUTHOR]

This paper presents an analysis of oxidation in olive oil TAG at different temperatures within a range of 40-60°C in darkness, as measured by the rate of formation of hydroperoxides, their decomposition products, and sensory and chemical flavor deterioration. At 60°C, the oxidation process was relatively fast, and all the indexes of the extent of oxidation behaved in a very similar way. The behaviors of the rate of formation of conjugated dienes (measured as the K232), of oxidized TAG (determined by HPLC), and of carbonyl compounds (measured as anisidine value) were very similar to that of the PV. The induction periods (IP) of the four indexes were less than 36 h. Nevertheless, the IP for K270 and the sum of oxidized TAG dimers and polymers were 5 d. At 50 and 40°C, the rate of formation of secondary oxidation products was lower. Residual linolenic acid or PUFA as determined by GC showed correlation coefficients higher than 0.999 with the Totox index at all of the assayed temperatures. The rancid recognition threshold corresponded to lower values of the oxidation indexes at lower temperature. Moreover, at all assayed temperatures, the rancidity threshold apparently coincided with the IP for the kinetics of 2,4-decadienal formation. [ABSTRACT FROM AUTHOR]

Using different bleaching materials to eliminate or reduce organic volatiles in deteriorated olive oils will positively affect its characteristics. This study aims to identify the volatiles of oxidized olive oil after physical bleaching using selected immobilized adsorbents. Oxidized olive oil was eluted using open-column chromatography packed with silica gel, bentonite, resin, Arabic gum, and charcoal at a 1:5 eluent system (w/v, adsorbent: oxidized olive oil). The smoke point was determined. The collected distilled vapor was injected into GC-MS to identify the volatiles eluted after partial refining with each of these bleaching compounds. The results showed that volatile compounds were quantitatively and qualitatively affected by the type of adsorbents used for the elution of olive oil and the smoking points of eluted oils. The most prominent detected volatile compounds were limonene (14.53%), piperitone (10.35%), isopropyl-5-methyl-(2E)-hexenal (8.6%), methyl octadecenoate (6.57%), and citronellyl acetate (5.87%). Both bentonite and resin were superior in decreasing the ratio of volatile compounds compared with other bleaching materials used. Resin immobilized medium was significantly affected (p < 0.05), raising the smoke point. These results highlighted some information regarding the characteristics of volatile compounds that result after the physical elution of olive oil through selected adsorbents. [ABSTRACT FROM AUTHOR]

In previous works on olive mill wastewater (OMW), secondary advanced oxidation treatment solved the problem related to the presence of phenolic compounds and considerable chemical oxygen demand. However, the effluent presented a significant salinity after this treatment. In this work, an adequate operation of a reverse osmosis (RO) membrane is addressed to ensure constant performance over a long period of time. In this paper, the effect of the operating parameters on the dynamic membrane rejection performance towards the target species was examined and discussed. Rejection efficiencies of all species were observed to follow a similar pattern, which consisted of slight initial improvement that further decreased over time. Rejection of both divalent ions remained constant at over 99% regardless of the operating conditions. Rejections were noticed to follow the order SO42-> Cl-> NO3- and Ca2+> Mg2+> K+> Na+, as a rule. Divalent species were moderately more highly rejected than monovalent ones, in accordance with their higher charge and molecular size, and sulfate anions were consistently rejected by over 99%. Finally, the RO membrane exiting treated effluent was depleted of the high electro conductivity initially present (above 97% rejection), permitting its re-use as good quality irrigation water (below 1 mS/cm). [ABSTRACT FROM AUTHOR]

Background: According to the regulations of the Neapolitan Pizza TSG, extra virgin olive oil must be exclusively used as topping ingredient, together with tomato for pizza marinara-type production. As, often deliberately, other oils are replaced by pizza makers for economical and organoleptic purposes, the present study was conducted to analyze the quality of pizza depending on the oil typology used. Methods: Chemical and sensory analyses were performed on olive oils and on pizza topping mix samples after cooking to detect changes due to the applied cooking processing. Results: The results revealed the best quality of a monovarietal olive oil (Ottobratica cv.) for their peculiar phenolic content related to the best oxidation stability after pizza's cooking, expressed as bioactive amounts and lower presence of undesired volatile compounds. Conclusions: The use of an extra virgin monovarietal olive oil, such as Ottobratica cv., in the topping of pizza is preferable to other oils, also EVOO, because of its higher quality, which is reflected in greater health and pleasant characteristics from a sensorial point of view. [ABSTRACT FROM AUTHOR]

This research investigates the effects of using different lipid formulations (100% beef fat, 85% beef fat+15% olive oil, or 70% beef fat+30% olive oil) in fermented turkey sausages on protein–lipid oxidation, in vitro digestibility, and related quality parameters. The use of olive oil results in decreased fat content, modified fatty acid profile, and increased pH value, acidity, and water activity, besides changes are recorded in instrumental quality and sensory features. Lipid oxidation is higher in samples with 30% olive oil than in the others. Carbonyl content increases depending on oil level and storage time. α‐aminoadipic semialdehyde is only detected in products containing 30% olive oil and their concentrations increased with storage. γ‐glutamic semialdehyde also increases by olive oil inclusion, but decrements are recorded during storage. Increasing olive oil results in increased pepsin digestibility but losses are recorded in both pepsin and trypsin plus α‐chymotrypsin digestion rates during storage. Practical applications: Inclusion of vegetable oils into meat product formulations has been preferred recently to supply healthier products, but in this situation, oxidative deterioration again becomes a considerable problem affecting overall quality. The data obtained from the present work wil contribute to understand the impacts of formulation and processing operations on the formation of oxidation products and change in digestibility, thereby to pioneer further research on this topic. [ABSTRACT FROM AUTHOR]

Generally the virgin olive oil (VOO) requires a cleaning operation that is performed using a vertical disc stack centrifuge representing the most important source of product oxidation. Natural settling represents an alternative to the oil/water separation but it results unsuitable for modern processes due to great amount of time required to perform the operation. In the present paper are reported the results of VOO cleaning through an enhanced sedimentation plant by hydrocyclone. Treatments have been compared by physical and chemical characterisation of VOO both after 48 h from extraction and after 180 days of shelf-life. The VOO cleaning by the enhanced sedimentation plant showed the capability to increase both processing capacity and VOO quality with respect to both VOO by vertical disc stack centrifuge and by natural sedimentation plant. VOO analyzed after 48 h and after 6 months showed a lower oxidation level for oil by enhanced sedimentation, better quality and suitability for prolonged shelf-life than oil by disc stack centrifuge. Moreover, even if disc stack centrifuge plant produces olive oil that is much more clean than oil by enhanced sedimentation plant the latter shows an improved long-term stability. Principal component analysis shows that storage time effect on VOO is quantifiable as a decrease in colour level and an increase in oxidation level. The enhanced sedimentation plant produces an olive oil with the highest amount of antioxidants and pigments, whereas the natural sedimentation plant produces an olive oil with lesser antioxidants and pigments and higher value for K270. [ABSTRACT FROM AUTHOR]

A meta-analysis on the effect of gamma irradiation on lipid oxidation products in raw chicken meat subjected to different temperatures of storage and packageing was carried out. A total of 11 studies were examined in regard to the peroxide value (POV) and thiobarbituric acid reactive substances (TBARS). The high heterogeneity in the studies was decisive for the selection of the random effects model applied on the raw mean difference (effect size) for the analysis of the data. The results of the meta-analysis showed that gamma irradiation increased the contents of the primary (POV) and secondary products (TBARS) of lipid oxidation in the raw chicken meat (P<0.001). Further, meta-regression and the examined covariates indicated significant influence of the dose of radiation on the formation of POV (P<0.001), whereas TBARS contents tended to depend on the package of the meat. In most of the studies included in the meta-analysis, the contents of the lipid oxidation products remained in acceptable levels and the treatment with gamma rays did not affect negatively the high nutritive value of the meat. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, the tocopherol contents, fatty-acid compositions and some oxidation indexes of olive (Olea europaea L.) pulp and kernel oils, originating from six cultivars, were determined. The tocopherol contents varied from 110±7.34 to 358±3.86μg/g in pulp oil and from 15.0±0.17 to 38.8±0.27μg/g in kernel oil. The major fatty acid in all cultivars was oleic acid, along with two other predominant fatty acids, palmitic and linoleic. The PCA results showed that the fatty acid profiles are similar in pulp and kernel. The calculated oxidizability value of the kernel oils was slightly worse than those of the pulp oils. However, the kernel oils have favorable values for the saturated fatty acid contents and for the unsaturated/saturated fatty acids ratio. The main outcome of this study revealed that the kernel oils can be used as suitable edible oils, with low tocopherol content, but with a more favorable fatty acids composition than their corresponding pulp oils. [Copyright &y& Elsevier]

This paper reports for the first time a discrimination study based on the antioxidant compounds, oxidative stability and volatile compounds of virgin olive oil samples obtained from fruits of the main Tunisian olive cultivar (Chemlali) using two methods of olive tree propagation (suckers and cuttings). There were significant differences between the oils from the two methods. Olive oil samples obtained from the fruits of trees from suckers had a higher content of oleic acid (63.8%), higher contents of chlorophyll and carotenoids (3.01 mg/ kg and 1.9 mg/kg respectively), a higher content of (E)-2 hexenal (66.1%) and a higher content in total phenols (890 mg/kg). Interestingly, more stable oil was obtained from the olives from suckers compared to the olives from cuttings. These results can be used to discriminate and to characterize the Chemlali olive oils from each origin of olive tree. [ABSTRACT FROM AUTHOR]

Abstract: The paper describes a study of thermal stress of three different samples of virgin olive oil in terms of oxidative stability. Fatty acid composition, evaluation of oxidative stability under forced conditions (OSI), determination of UV-spectrophotometric oxidation indexes (k 232 and k 270) and spectral properties were explored along the thermal treatment. The samples were subjected to heating treatment at 180°C and evaluated after 0, 30, 60, 90, 120, 150 and 180min. Middle infrared (MIR) and visible–near infrared (Vis–NIR) spectra were elaborated by partial least squares modelling to individualise regions and bands where critical variations were present. Two bands were found as principal influential ones (1245–1180cm−1 and 1150–1030cm−1) on MIR while one primary region was identified on Vis–NIR (2200–1325cm−1). [Copyright &y& Elsevier]

Abstract: In this paper water droplets dispersed in olive oils were used as containers of l-ascorbic acid and its inhibitory effect on lipid oxidation was studied. In detail, olive oil samples were emulsified by adding a certain quantity of vitamin C aqueous solutions and then oxidized by UV light. Data collected from sample analysis by optical microscopy were used to calculate the average droplets parameters and to characterize the droplet size distribution function. The results revealed a strong correlation between the initial rate of hydroperoxide formation and the specific surface area of aqueous dispersed phase. Such correlation has been explained as the consequence of a synergistic interaction between the ascorbic acid contained in the droplets and the natural tocopherols present in olive oil. A key role is played by the water–olive oil interface which is the boundary where the synergisms take place. [Copyright &y& Elsevier]

Among several parameters defined for the commercial classes of virgins olive oils (VOOs), there is one, the fatty acid ethyl ester (FAEE), that is only define for the best quality (EVOO). Fruit condition mainly determine these compounds, although, extraction process or deplorable storage condition could rise them up. The FAEE oxidation compound are originated by adding an alcohol chain into the oil molecule. Therefore, the hypothesis of this study is that the inherent constitution of FAEE entails a modification of the volatile profile of oils and olives and this is significant enough to be detected using an electronic nose. With this aim, different samples of olives and oils were analyzed in an accredited laboratory. On the other hand, volatiles from the same samples were captured by an electronic nose. The classification problem was analyzed from two points of view or models. The first was to classify fruits and oils based on whether they are within or outside the legal limits. And the second problem was oriented to classify fruits and oils based on their high or low FAEE content but being within the legal limits. To solve this problem, three classification algorithms were evaluated: Naïve Bayes (NB), Multilayer Perceptron (MLP) and Sequential Minimal Optimization (SMO). For the first model, a well-classified sample rate of 80.3% was obtained for NB and 100% for SMO and MLP, for measurements on oils. The same model evaluated with measurements on olives yielded a success rate of 87.5% with NB, 87.7% with MLP and 82.1% with SMO. For the second model, the success rates remained within the same orders of magnitude. For measurements on oils, the results were 89.7% for NB, 92.5% for MLP and 100% for SMO. And for measurements on olives the results were 77.9% for NB, 88.6% for MLP and 90.9% for SMO. In all cases, the characteristics that worked best were those obtained from the first derivative of the electronic nose response. Based on these results, the e-nose demonstrate to be a non-invasive technology suitable for the classification of olive fruits and oils based on their FAEE content. [ABSTRACT FROM AUTHOR]

Summary: Edible oleogels, with three oil types (olive, sunflower and flaxseed), hydroxypropylmethylcellulose (HPMC) and xanthan gum (XG), as structuring agents, were developed using the emulsion‐template approach, and subsequent drying of the emulsions using conventional or vacuum drying. Our results showed that for both drying methods, well‐structured oleogels were obtained using olive and sunflower oils for the preparation. These oleogels showed oil losses ˂10% after 35 days of storage. However, unstructured non‐homogeneous oleogels were obtained when using flaxseed oil and conventional drying, while it was not feasible to develop flaxseed oleogel with vacuum drying. Oleogels showed interesting rheological properties, including a high oleogel strength with an elastic modulus of the order 104–105 Pa, weak dependence on frequency, and good thermostability. Moreover, high oxidative stability was obtained for olive oil oleogels, using both conventional and vacuum drying, and for sunflower oleogels using vacuum drying. Still, the initial oxidation rates of sunflower oleogels using conventional drying should be improved in future studies. [ABSTRACT FROM AUTHOR]

The reaction of oil with oxygen can cause structural degradation with the development of rancid flavours that reduces the organoleptic characteristics and formation of oxidation products with consequent reduction in shelf life, loss of taste, flavour, food quality and detrimental effect on human health. Therefore, the overall quality of oil in foods contributes ultimately to the nutritional quality of that food. Thus, this study was at evaluating the quality of some food oils. The various oils were extracted locally and the quality was evaluated based on the peroxide values, iodine values, saponification number, free fatty acids and cholesterol values. Ripped and unripe plantain was screened for their Dinitrophenylpincryl hydrazine (DPPH) and Nitric oxide (NO) radical scavenging activity and quantitative alkaloid, flavonoids and tannin content. The result showed that out of all the food oil, coconut oil outflanked the others in terms quality as reflected in all the reference chemical parameters. The ripped plantain showed a better antioxidant activity than the unripe. Therefore, the result of this study affirms the quality and oxidative stability of coconut oil and that it could have a longer shelf life. The antioxidant activity of the ripped plantain maybe associated with its higher tannin and flavonoids content. [ABSTRACT FROM AUTHOR]

Monitoring or preventing oxidation processes in foods, particularly heterogeneous systems or highly oxidizable lipids, has become a primary issue. Traditional approaches often fail in pursuing this aim. At the same time, the prediction in laboratory of the efficacy of antioxidant molecules and technologies often fails when challenging reality. A change in the traditional paradigm used to conceive oxidation processes and their monitoring could be a key. In the present work, an “omics” approach is suggested for the evaluation of oxidation in food lipids and of the role played by minor compounds. This holistic and comprehensive, hypothesis‐generating approach is applied to a typical research case: highly‐purified olive oil added with increasing amounts of purified free fatty acids (FFA). A comprehensive profile (“oxidome”) of oxidation products is outlined during the accelerated oxidation. The pathways considered are FFA and triacyglycerol oxidation, triacyglycerol polymerization, volatile compounds formation as well as their further oxidation. FFA affectes the overall balance of the oxidation pathways and consequently causes a drift in the evolution of the pattern of oxidation products. The balance between accelerating activity of FFA toward triacylglycerol oxidation and their high susceptibility to undergo oxidation turnes out to be dose‐dependent and time‐related, and shiftes the resulting oxidation profile of the oil. The omics approach to oxidation products profiling provides new insight into oxidation processes. “Oxidomics” could be helpful to deepen the insight into unresolved issues of oxidation, going beyond the usual single‐ or few‐marker approach. Practical Applications: This research suggests a new paradigm for approaching food lipid oxidation. Unresolved practical issues regarding food spoilage and shelf‐life, waste reduction, keeping of healthy properties are increasing along the increasing formulation of complex and dispersed systems, use of healthy highly unsaturated fatty acids and bioactive antioxidants, attention paid by consumers and industries to nutritional, sensory, health properties of foods. The new paradigm suggests going beyond the usually adopted single‐ or few‐marker approach and to consider the pattern of oxidation reactions and products as a whole, in order to better describe and predict its changes and the effects of external factors as well as added molecules. “Oxidomics” is a new paradigm for lipid oxidation, with a holistic approach to the system and evaluating a pattern of oxidation products and its changes. [ABSTRACT FROM AUTHOR]

Background and Objectives: Virgin olive oil is a vastly consumed product, with widespread appreciation for its good nutritional and health properties. However, oxidation can reduce its quality. The aim of this study was to investigate how the essential oil of Zataria multiflora (Shirazi thyme) can contribute to the prevention of virgin olive oil oxidation in comparison with the actions of α-tocopherol and BHT. Furthermore, the synergistic activities of citric acid with BHT, Z. multiflora essential oil, and α-tocopherol were investigated. Materials and Methods: Antioxidant activity of the essential oil was determined using radical scavenging capacity and reducing power assays. Virgin olive oil samples were stored at 60±1 °C in closed amber bottles for 16 days. Oxidation levels of samples were determined by measuring peroxide, anisidine, TOTOX, K232, K268 values, and chlorophyll and carotenoid contents of the samples during the storage period. Results: Z. multiflora essential oil exhibited a significant radical scavenging capacity and reducing power. Peroxide, anisidine, TOTOX, K232, and K268 values of samples containing Z. multiflora essential oil were significantly lower than those of the control group (without antioxidants). Z. multiflora essential oil reduced the oxidation of virgin olive oil to the same extent as BHT did. Z. multiflora essential oil was more effective than α-tocopherol. The synergistic activities between citric acid and the various compounds, i.e. BHT, Z. multiflora essential oil, and α-tocopherol were 2.42%, 4.74%, 1.28% respectively. Conclusions: In general, Z. multiflora essential oil can be considered as natural antioxidant for the stabilization of virgin olive oil against oxidation. [ABSTRACT FROM AUTHOR]

In this work, a mixed oil formulation was developed to obtain a product rich in essential fatty acids and with reduced ratio of linoleic and linolenic fatty acids. The formulations were optimized using techniques of multivariate mixture designs. Three formulations of different compositions were chosen and they were assessed regarding oxidative stability, sensory acceptance, fatty acid composition, phytosterols, and tocopherols. The formulation with improved sensory acceptance was composed of 85% of extra-virgin olive oil, 3% of linseed oil, and 12% of safflower oil. The new formulation showed the lowest ratio of linoleic and linolenic acids when compared to the extra-virgin olive oil, higher oxidative stability, and higher levels of phytosterols and tocopherols. Practical applications: The mixed oil formulation developed here possess practical application as a product nutritionally enriched for use as ingredient in several food products. It can also be largely used in industrial scale to enrich food products with high contents of essential fatty acids, phytosterols and tocopherols, helping to obtain final products with a more adequate n-6/n-3 fatty acids ratio and promoting health benefits through its consumption. In this study, a mixed oil formulation which contains high levels of essential fatty acids and reduced ratio of n-6/n-3 to be used as ingredient in foods is developed. The main parameters related to oxidative stability, chemical composition, and sensory acceptance of the final product are evaluated. [ABSTRACT FROM AUTHOR]

In this study, extra virgin olive oil (EVOO) was mixed with sesame seed oil (SSO) at different concentrations (100:0, 90:10, 80:20, 70:30 and 60:40 w/w) and stored for 90 days at room conditions. To see the effect of mixing level and storage period, a combined design having two mixtures (EVOO and SSO) and one process factor (storage period) was used. Main oxidation parameters (free fatty acid content, refractive index, peroxide value and p-anisidine value) and major fatty acid composition of the samples were characterized. It was observed that EVOO is quite sensitive to oxidation compared to SSO and increase of SSO in the blended oil samples decreased the oxidation of the product during storage. Major fatty acids were palmitic, oleic and linoleic acids. Addition of SSO caused a significantly change in the fatty acid composition. The results showed that EVOO could be stored for longer time by mixing of SSO having strong antioxidant activity. [ABSTRACT FROM AUTHOR]

The deep changes caused by oxidation on virgin olive oil (VOO), which is a high-quality product, not subjected to ameliorative refining, make this phenomenon one of the most studied. Among the techniques used to study oxidation in olive oil, thermal analysis (TA) provides useful information about the thermal behavior of the samples as affected by oxidation. Thermogravimetry (TG), measuring the changes in the sample mass, can monitor the kinetics of oil mass loss in decomposition processes or oxidation and has been found particularly useful, especially when operating simultaneously with Differential Thermal Analysis (DTA) or Differential Scanning Calorimetry (DSC). The DSC thermal curves of olive oil, both on cooling and heating, has been found to be largely influenced by the oxidative status of the samples and different statistical approaches have been successfully proposed to correlate the thermal parameters with the conventional chemical indicators of oxidation. DSC can be also used to study the kinetics of phase transition phenomena as affected by oxidation. This review provides an exhaustive survey about the application of the thermoanalytical techniques on this topic proposing them as as a fast and green alternative to conventional chemical methods. Practical applications: The evaluation of the oxidative status of olive oil requires the development of simple and fast analytical techniques. The most used analytical methods are based on the chemical evaluation of the presence of molecules markers of lipid oxidation, but thermal analysis may provide a fast and green tool in this field, as it does not require sample preparation and use of solvents. The application of thermal analysis for the assessment of the oxidative degradation of olive oil has today reached numerous evidences that attest its actual applicability, and they are all summarized in this review. By these studies it is possible to put in evidence its ability to give qualitative information about the oxidative status of olive oil, both in terms of fatty substance degradation and presence of oxidation molecules that could be very helpful in the field of quality assurance for this high-quality vegetable oil. Thermal analysis as a valuable tool to evaluate olive oil oxidation without sample preparation or use of solvents. [ABSTRACT FROM AUTHOR]

A simple, precise, accurate and selective method was developed and validated for determination of malondialdehyde (MDA) in olive oil. Separation was achieved on a reversed-phase C column using a mobile phase consisting of methanol/0.8 % phosphoric acid (10:90, v/v), at a flow rate of 1.0 ml/min and UV detection at 220 nm. This method was validated according to the requirements for new methods, which include accuracy, precision, selectivity, robustness, a limit of detection, limit of quantitation (LOQ), linearity and range. The current method demonstrated good linearity over the range of 0.5-1000 ppm of MDA with r greater than 0.999. The recovery of MDA in olive oil ranged from 97.1 to 99.1 %. The method was selective where MDA was distinctly separated from other compounds of the oil with good resolution. The method was also precise where the RSD of the peak areas of replicate injections of MDA standard solution were less than 1 %. The degree of reproducibility of the results obtained as a result of small deliberate variations in the method parameters and by changing the analytical operators proved that the method is robust and rugged. The low LOQ of MDA (0.5 ppm) using this method enables quantitation of MDA at low concentration. [ABSTRACT FROM AUTHOR]

Superoxide dismutase (SOD, EC1.15.1.1) is a family of enzymes, which remove superoxide anion (O) from the cells of living organisms. The aim of this study was to describe antioxidative properties of SOD with regard to the protection of unsaturated fatty acids (UFA) from peroxidative damage and to compare this effect with butylated hydroxytoluene (BHT). In this experiment, Cu, Zn-SOD from hen's egg yolk with a mass of 15.59 ± 0.38 kDa and pI 6.58 ± 0.10, 6.41 ± 0.08 and 6.30 ± 0.15 was used to protect fatty acids from peroxidative damage in vegetable oil (sunflower oil and olive oil) during 200 days of storage at different temperatures-4, 20 and 35 °C. Antioxidative properties of SOD and BHT were expressed as the ratio of unsaturated to saturated fatty acids (SFA) in samples after 50, 100 and 200 days of storage as well as the percentage content of selected fatty acids in the examined oils. SOD from egg yolk showed the same or better antioxidant properties with regard to the concentration of linoleic acid (C18:2) contained in sunflower oil and olive oil than the corresponding concentrations of BHT during 200-day storage at 4, 20 and 35 °C. The concentration of linoleic acid (C18:2) in the sample with SOD was significantly higher during storage at 35 °C on day 200. At all storage temperatures, the ratio of SFA to UFA in samples with the addition of SOD was statistically higher than in oils stored without the antioxidant. With regard to linoleic acid (C18:2), SOD proved to be a better antioxidant than BHT. The results demonstrated better antioxidant properties of SOD from hen's eggs compared with the same concentrations of BHT at elevated temperatures (at 20 and 35 °C) in oil with a high content of UFA. No negative antioxidative effect (worse than that of BHT at a corresponding concentration) of the addition of SOD from egg yolk on fatty acid composition of the tested samples was observed. Though further research is necessary, SOD from hen's egg yolk seems to be a promising natural antioxidant of vegetable oils. [ABSTRACT FROM AUTHOR]

Squalene (SQ), a precursor of sterols and terpenoids is a functional lipid of high importance in the food and pharmaceutical sectors. SQ oxidation studies are rather limited compared with those for other olefins. The aim of the present study was to monitor the formation of SQ oxidation products under different conditions (temperature, air supply), to characterise the most abundant of them by spectroscopic techniques and then examine their pro-oxidant activity in a model lipid substrate. Squalane (SQA), the saturated analogue of SQ, was used as a reference compound. FT-MIR analysis indicated the presence of alcohols, epoxides, aldehydes, and ketones. GC-MS was used to characterise SQ primary oxidation and scission products. The presence of epoxides was further confirmed by means of 1H NMR and 13C NMR spectroscopy. It could be argued that SQ stability is due to its stereochemistry and specifically to the presence of methyl groups next to the double bonds. The pro-oxidant activity of SQ oxidation products was evident at 62 and 40°C and suppressed only in the presence of primary antioxidants, not of SQ. The present work adds to the characterisation of SQ oxidised products. To our knowledge their pro-oxidant activity has never been examined before. Practical applications: Characterisation of squalene oxidation products and assessment of their activity as pro-oxidants present both scientific interest regarding the kinetics and product identity as well as a practical impact in case this bioactive lipid is provided for consumption as a functional product. In the past, cholesterol oxidation products and more recently phytosterol ones attracted the interest of researchers, who studied the stability of the respective parent compounds for food safety reasons. Monitoring of the formation of SQ oxidation products under different conditions (temperature, air supply) and chemical characterisation of the most abundant of them by spectroscopic techniques. Examination of their pro-oxidant activity in a model lipid substrate. Squalene may exert a weak antioxidant activity due to competitive oxidation phenomena with the lipid substrate while its oxidation products have a pro-oxidant activity on purified olive oil model substrate that was suppressed only in the presence of primary antioxidants. [ABSTRACT FROM AUTHOR]

Storage conditions can affect the stability and quality of extra virgin olive oil (EVOO). While many studies have reported the influence of high temperature and light exposure during storage, little is known on the influence of the cold storage. The aim of this study was to evaluate the effect of different storage conditions (25, 4.5 and −27 °C) on the various compositions of EVOO and to determine if cold storage will prolong shelf-life by retarding hydrolysis and oxidation. The changes of quality indices (FFA, PV, and UV) and natural antioxidants such as α-tocopherol and phenolic compounds were evaluated periodically during storage. The characterization and quantification of phenolics were achieved by ultra-performance liquid chromatography-diode array detector (UPLC-DAD). In addition, 1, 2-diacylglycerols (DAGs), pyropheophytin A (PPP) were measured to indicate thermal degradation during storage. [ABSTRACT FROM AUTHOR]

The effect of storage conditions (light, temperature, container types) and time on the quality of natural olive oils from different cultivars and Australian regions were studied. The oils' changing quality was monitored through several physico-chemical methods (free fatty acids, peroxide value, UV-spectrometry (K, K and Δ K), induction time, total polyphenol content, bitterness, pyropheophytin a and 1,2-diacyl-glycerol content) and sensory analysis over 24 months. Pyropheophytins a and 1,2-diacyl-glycerols criteria showed very good performance as indicators of overall olive oil quality and freshness as well as highlighting any problems during the storage of the product. Pyropheophytin a increment averaged 7 % per year and the 1,2-diacyl-glycerols decreased at an average of 23 % per year at normal storage conditions over time. [ABSTRACT FROM AUTHOR]

Various studies are present in literature about the nutritional and sensorial characteristics of preserved tomato products and minimally processed products. To the best of our knowledge, there are no data in literature concerning the tomato-based pâtés, suitable as seasoning for pasta, salads and sandwiches. The aim of this work was to characterize two types of tomatobased pâtés in terms of volatile compounds profile, lipid fraction degradation and antioxidant contents as a function of the ingredient formulation. The tomato-based pâtés showed a different aromatic profile, with particular reference to volatile compounds deriving from the raw materials and lipid autoxidation. Significant differences were also observed for the oxidative and hydrolytic degradation level of the lipid fraction, as well as total phenols and flavonoids content. The differences observed were linked to the ingredient formulation used. In particular, the addition of minced mushrooms, chilli and parsley involved a development of terpenic volatile compounds, while when extra virgin olive oil was used significantly higher percent contents of aldehydes and ketones were found, as well as a minor oxidative degradation of lipid fraction. Also total phenols and flavonoids content were influenced by the ingredient formulation, while no differences were observed for the lycopene content. [ABSTRACT FROM AUTHOR]

Refined olive and refined soybean oils (RSO) have been analyzed in order to evaluate their physicochemical behavior during potatoes pan-frying. These refined oils exhibit significant variations in the physicochemical parameters when heated. A significant decrease ( p<0.001) was practically observed in all analytical determination values except the induction time which showed a significant increase ( p<0.001) with the enrichment with hydrolyzate olive leaf hydroxytyrosol-rich extract at 500 ppm during pan-frying. In fact, such enrichment has shown a remarkable resistance to oxidative deterioration, and the formation of trans-fatty acids (TFA) was found to be lower in the enriched refined oil samples during pan-frying. Such results have proven that not only is hydroxytyrosol-rich extract excellent antioxidant enrichment for refined olive and RSOs during pan-frying, but also it can be useful as substitute for synthetic ones. This study has shown that enriching refined oils with easily-found and cheap natural plant extracts could extend their usage life. Practical applications: The results of this research study have shown that refined pan-frying oils can successfully be enriched with hydrolyzate olive leaf hydroxytyrosol-rich extract at 500 ppm in order to enhance thermo-oxidative stability and reduce significantly the formation of trans-fatty acids. The hydrolyzate extract was found to be very suitable for this purpose. These materials are common agro-food by-products and can be produced very easily at a low cost. Besides, this type of enrichment may enable consumers to get some beneficial phenolic compounds through fried food consumption. In addition, these types of applications may open another area for marketing the named extract of natural origin. [ABSTRACT FROM AUTHOR]

Extra virgin olive oil is highly appreciated worldwide for its healthy and organoleptic properties. From the variety of compounds present in the oil, phenols stand out, not only for producing the bitter-pungent perception but also for their antioxidant properties, which contribute to human health protection. The addition of plants can change the phenolic profile due to a migration of plant antioxidants to the oil. The aim of this work was to study the evolution of the oxidative process of extra virgin olive oil under mild storage conditions for 8 months, monitoring the individual content of 15 phenols by High Performance Liquid Chromatography (HPLC) and the changes of the phenolic profile of the non-flavoured oil compared with the same flavoured (rosemary and basil) oil. The oxidative alteration was more marked in virgin than in flavoured oils, where it happened slowly. Throughout storage, the behaviour of the phenols varied, resulting in a decrease in their concentration, except in the case of tyrosol and hydroxytyrosol. The addition of plants had an antioxidant effect, slowing down the oxidative process, which prolongs the shelf life of the flavoured oil compared to the unflavoured oil. Furthermore, multivariate statistical analyses allowed the classification and differentiation of the different samples. [ABSTRACT FROM AUTHOR]

Oxidative stability (OS) of virgin olive oil is affected by different antioxidants whose levels may be influenced by nutrients availability. Changes in OS of virgin olive oil and antioxidants levels were evaluated according to foliar application of six nutrient-based treatments: T1 (rich in nitrogen), T2 (rich in boron, magnesium, sulfur and manganese), T3 (rich in phosphorus and potassium), T4 (rich in phosphorus and calcium), T5 (application of T1 and T2) and T6 (application of T1, T2, T3 and T4). The foliar applications were carried out during two successive growing seasons and oils were extracted and analyzed at the end of the experiment (after 2 years). T3 and T6 treatments improved oil stability by increasing the content of antioxidants, while T2 and T4 affected negatively the antioxidant profile of oils. Measured correlations between OS and compositional variables showed that total phenols had the highest value ( R = 0.937, p < 0.001), followed by α-tocopherol ( R = 0.775, p < 0.001) and oleic/linoleic ratio ( R = 0.625, p < 0.05). These findings suggest that the changing levels of antioxidant compounds, due to fertilization, may be used to obtain oils with the highest quality. [ABSTRACT FROM AUTHOR]

The harvest period is one of the most important factors influencing olive oil quality. This period is extended for several months and the late-extracted olive oils are characterized by quality loss and reduced resistance to oxidation. The aim of this work was to verify the effect of olive leaves addition during the oil extraction process in the olive oils quality and composition. In two consecutive years (2009 and 2010), different olive leaves amounts (1%, 2.5%, 5% and 10% w/ w) were added during the extraction process of cv. Cobrançosa olive fruits, collected in the late season. Standard quality parameters, oxidative stability, fatty acids profile, tocopherols, chlorophylls, and carotenoids contents were evaluated. Olive leaves addition induces a slight increase in acidity, peroxide value, K, and K without compromising olive oils classification, but the resistance to oxidation was significantly improved. Vitamin E increased nearly 30% with 10% of leaves added mainly due to the considerable increase in α-tocopherol. A similar effect was observed in the contents of chlorophylls (chlorophyll a and pheophytin a) and carotenoids (lutein and β-carotene), that attributed a more intense greener pigmentation and enhanced nutritional attributes. Significant correlations were observed for several parameters with the amounts of leaves added. Moreover, leaves addition modified the characteristics and composition of the olive oils in a way that was possible to discriminate and to classify each group. [ABSTRACT FROM AUTHOR]