Profile of phenolic compounds of Brazilian virgin olive oils by rapid resolution liquid chromatography coupled to electrospray ionisation time-of-flight mass spectrometry (RRLC–ESI-TOF-MS)

Characterization of Phenolic Compounds in Extra Virgin Olive Oil from Granada (Spain) and Evaluation of Its Neuroprotective Action

The olive oil sector is a fundamental food in the Mediterranean diet. It has been demonstrated that the consumption of extra virgin olive oil (EVOO) with a high content of phenolic compounds is beneficial in the prevention and/or treatment of many diseases. The main objective of this work was to study the relationship between the content of phenolic compounds and the in vitro neuroprotective and anti-inflammatory activity of EVOOs from two PDOs in the province of Granada. To this purpose, the amounts of phenolic compounds were determined by liquid chromatography coupled to mass spectrometry (HPLC-MS) and the inhibitory activity of acetylcholinesterase (AChE) and cyclooxygenase-2 (COX-2) enzymes by spectrophotometric and fluorimetric assays. The main families identified were phenolic alcohols, secoiridoids, lignans, flavonoids, and phenolic acids. The EVOO samples with the highest total concentration of compounds and the highest inhibitory activity belonged to the Picual and Manzanillo varieties. Statistical analysis showed a positive correlation between identified compounds and AChE and COX-2 inhibitory activity, except for lignans. These results confirm EVOO's compounds possess neuroprotective potential.

Bioactive compounds of honey from different regions of Brazil: the effect of simulated gastrointestinal digestion on antioxidant and antimicrobial properties

Monofloral and multifloral honey produced in different regions may have different bioactive compounds and antioxidant capacities, resulting in changes in the antimicrobial activity of honey. However, many of these compounds degrade due to the extreme digestion conditions, which may inhibit the antimicrobial activity. Given this context, this study aimed to describe the bioactive compounds of honey produced in Brazil and verify if honey samples from different botanical and geographical origins differ in bioactive compounds, and if honey maintains its antimicrobial activity after digestion simulation. Multivariate analysis was used to identify characteristics that differentiated the honey samples according to the botanical and geographical origin criteria. The amount of the bioactive compounds varied significantly: the total phenolic compound content varied from 20.49 to 101.44 mg GAE per 100 g, flavonoids varied from 1.41 to 13.52 mg QE per 100 g, phenolic acids varied from 13.61 to 56.41 mg CAE per 100 g, and carotenoids varied from 0.66 to 4.27 mg β-carotene per g. Multifloral honey (H22) produced in the dry season of northeastern Brazil presented the highest bioactive compound concentration except for the carotenoid content. HPLC-MS analysis showed the presence of six hydroxybenzoic acids, four hydroxycinnamic acids, eight flavonols, three flavanones, two flavones and two isoflavonoids; Pterodon pubescens monofloral honey (H14) from midwestern Brazil stood out in terms of the carotenoid content. All analyzed honey samples exhibited antimicrobial activity against Staphylococcus aureus and Escherichia coli bacteria before digestive process simulation, and bacteria were inhibited during in vitro digestion; this activity decreased during the simulation of the oral phase, remained in the gastric phase, and disappeared in the intestinal phase.

Characterization of olive oil flavored with Brazilian pink pepper (Schinus terebinthifolius Raddi) in different maceration processes

The present study aimed to evaluate two different processes of olive oil aromatization with Schinus terebinthifolius Raddi, conventional maceration (CM) and ultrasound-assisted maceration (UM), and their influence on quality parameters, total phenolic compounds (TPC), fatty acid profile (FA), volatile organic compounds (VOCs), antioxidant capacity, and oxidative stability. Flavoring reduced peroxide values, although it increased free fatty acids and extinction coefficients. The flavorization process did not change the FA profile, which showed oleic acid as a major compound. The VOCs varied and the migration of oxygenated monoterpenes were more effective in UM-flavored olive oil compared to its CM counterpart. All flavored olive oils presented higher oxidative stability than the control samples and UM-flavored olive oil was highlighted for its higher antioxidant activity. These findings proved that aromatization with pink pepper assisted by ultrasound may be an alternative to improve olive oil quality and create a new competitive flavored product.

Evaluating Quality Parameters, the Metabolic Profile, and Other Typical Features of Selected Commercial Extra Virgin Olive Oils from Brazil

The production of extra virgin olive oil (EVOO) in Brazil developed quite recently, and information on commercial Brazilian EVOO's typical features is very scarce. In just one of the previously published works on Brazilian olive oil, the assessed samples were commercially available. In this study, a comprehensive characterization of EVOO samples acquired at local stores (at Rio de Janeiro and Rio Grande do Sul, from the two most prevalent cultivars, Arbequina and Koroneiki) was carried out considering the most relevant quality parameters, antioxidant capacity, oxidative stability, total phenolic content, fatty acid composition, and minor component metabolic profiling. The latter included: (1) the determination of individual phenolic compounds (belonging to four diverse chemical classes) and triterpenic acids by means of a powerful multi-class reversed-phase LC-MS method; (2) the quantitative profiling of tocopherols, phytosterols, and pigments by normal-phase LC-DAD/fluorescence; and (3) the quantitative appraisal of the volatile pattern of the oils by solid-phase microextraction (SPME)-gas chromatography (GC)-MS. By applying these methods, the concentrations of approximately 70 minor compounds were determined in commercial EVOOs from Brazil. To the best of our knowledge, the content of a very large number of phenolic compounds of those determined in the current report (mainly secoiridoids), the three triterpenic acids (maslinic, betulinic, and oleanolic acids), and the individual chlorophyll derivatives had not been previously evaluated in Brazilian EVOOs. The present work provides a broad picture of the compositional profile and other parameters of relevance of selected commercial Brazilian EVOOs available on local markets, describing their typicity and most particular features, some of which are known to have potential impacts on consumers' health.

Application of High Resolution Mass Spectrometric methods coupled with chemometric techniques in olive oil authenticity studies - A review

Extra Virgin Olive Oil (EVOO), the emblematic food of the Mediterranean diet, is recognized for its nutritional value and beneficial health effects. The main authenticity issues associated with EVOO's quality involve the organoleptic properties (EVOO or defective), mislabeling of production type (organic or conventional), variety and geographical origin, and adulteration. Currently, there is an emerging need to characterize EVOOs and evaluate their genuineness. This can be achieved through the development of analytical methodologies applying advanced "omics" technologies and the investigation of EVOOs chemical fingerprints. The objective of this review is to demonstrate the analytical performance of High Resolution Mass Spectrometry (HRMS) in the field of food authenticity assessment, allowing the determination of a wide range of food constituents with exceptional identification capabilities. HRMS-based workflows used for the investigation of critical olive oil authenticity issues are presented and discussed, combined with advanced data processing, comprehensive data mining and chemometric tools. The use of unsupervised classification tools, such as Principal Component Analysis (PCA) and Hierarchical Clustering Analysis (HCA), as well as supervised classification techniques, including Linear Discriminant Analysis (LDA), Support Vector Machine (SVM), Partial Least Square Discriminant Analysis (PLS-DA), Orthogonal Projection to Latent Structure-Discriminant Analysis (OPLS-DA), Counter Propagation Artificial Neural Networks (CP-ANNs), Self-Organizing Maps (SOMs) and Random Forest (RF) is summarized. The combination of HRMS methodologies with chemometrics improves the quality and reliability of the conclusions from experimental data (profile or fingerprints), provides valuable information suggesting potential authenticity markers and is widely applied in food authenticity studies.

In House Validated UHPLC Protocol for the Determination of the Total Hydroxytyrosol and Tyrosol Content in Virgin Olive Oil Fit for the Purpose of the Health Claim Introduced by the EC Regulation 432/2012 for "Olive Oil Polyphenols"

An ongoing challenge in olive oil analytics is the development of a reliable procedure that can draw the consensus of all interested parties regarding the quantification of concentrations above the required minimum value of 5 mg of bioactive “olive oil polyphenols” per 20 g of the oil, to fulfill the health claim introduced by the European Commission (EC) Regulation 432/2012. An in-house validated ultra-high performance liquid chromatography (UHPLC) protocol fit for this purpose is proposed. It relies on quantification of the total hydroxytyrsol (Htyr) and tyrosol (Tyr) content in the virgin olive oil (VOO) polar fraction (PF) before and after acidic hydrolysis of their bound forms. PF extraction and hydrolysis conditions were as previously reported. The chromatographic run lasts ~1/3 of the time needed under high performance liquid chromatography (HPLC) conditions, this was also examined. Eluent consumption for the same piece of information was 6-fold less. Apart from being cost effective, a larger number of samples can be analyzed daily with less environmental impact. Two external curves, detection at 280 nm and correction factors for molecular weight difference are proposed. The method, which is fit for purpose, is selective, robust with satisfactory precision (percentage relative standard deviation (%RSD) values < 11%) and recoveries higher than 87.6% for the target analytes (Htyr, Tyr). Standard operational procedures are easy to apply in the olive oil sector.

Application of an advanced and wide scope non-target screening workflow with LC-ESI-QTOF-MS and chemometrics for the classification of the Greek olive oil varieties

An optimized and validated LC-ESI-QTOF-MS method with an integrated non-target screening workflow was applied in the investigation of the metabolomic profile of 51 Greek monovarietal extra virgin olive oils (EVOOs) from the varieties: Manaki, Ladoelia, Koroneiki, Amfissis, Chalkidikis and Kolovi. Data processing was carried out with the R language and XCMS package. A local database consisting of 1608 compounds naturally occurring in different organs of Olea Europa L. was compiled in order to accelerate the identification workflow. The preliminary examination of the distribution of EVOOs toward their cultivars was achieved by Principal Component Analysis (PCA). Ant Colony Optimization-Random Forest (ACO-RF) was developed to prioritize over 250 features and to establish a classification tree. Apigenin, vanillic acid, luteolin 7-methyl ether and oleocanthal were suggested as the markers responsible for the classification of Greek EVOOs' cultivars.

Evaluation of phenolic composition and antioxidant activity changes in olive flowers during development using HPLC/DAD and LC-MS/MS

Olive fruit and leaves have been extensively studied for their chemical compositions and biological activities. However, less attention has been given to its flowers. The present research was achieved on Tunisian olive flowers. It aimed at studying the effects of flower development on phenolic compounds and antioxidant activity. The extracts were analyzed using high performance liquid chromatography coupled to diode array detection (HPLC/DAD) and coupled to mass spectrometry (LC-MS/MS). The HPLC/DAD analysis indicated that oleuropein aglycon (from 1.158 to 3.746 g/kg), followed by hydroxytyrosol (from 0.168 to 1.581 g/kg) and oleoside (from 0.143 to 1.325 g/kg) were the predominant phenolics in olive flowers extracts during development stages. Twenty compounds have been identified, revealing the complex profile of olive flowers, composed, in order of abundance, by secoiridoids, phenolic alcohols, lignans, flavonoids and phenolic acids. Total phenolic contents increased from 2.455 to 8.541 g/kg Gallic acid equivalent per kg of fresh flowers during all steps of the flower development. A correlation between antioxidant activity and total phenolic contents was determined.

Phenolic Compounds Profiling of Virgin Olive Oils from Different Varieties Cultivated in Mendoza, Argentina, by Using Liquid Chromatography-Mass Spectrometry

The aim of this work was to achieve a preliminary characterization of the profile of the phenolic fraction of virgin olive oils (VOOs) from Maipú (Mendoza, Argentina). Thus, 25 commercial VOO samples from Arauco, Arbequina, Picual, Frantoio, Changlot, Empeltre, Nevadillo, Manzanilla, and Coratina (both monovarietals and blends) were analyzed using LC-ESI-QTOF MS and LC-ESI-IT MS for identification and quantification purposes, respectively. A rapid LC method (15 min) accomplished quantitative information about a total of 40 phenolic compounds, including secoiridoid derivatives, which have not been evaluated before in samples coming from the subregion so-called Maipú (Mendoza province, Argentina). The results make evident that olive oils coming from Mendoza can be considered as important sources of phenolic bioactive compounds, exhibiting similar phenolic compound levels to those shown by oils from other typical world production regions. Moreover, some distinctive features of the Arauco variety (Argentinean autochthonous variety) were pointed out; indeed, a correlation between flavonoids content and botanical variety was established herewith.

Liquid chromatography-high resolution mass spectrometry for the analysis of phytochemicals in vegetal-derived food and beverages

The recent years witnessed a change in the perception of nutrition. Diet does not only provide nutrients to meet the metabolic requirements of the body, but it also constitutes an active way for the consumption of compounds beneficial for human health. Fruit and vegetables are an excellent source of such compounds, thus the growing interest in characterizing phytochemical sources, structures and activities. Given the interest for phytochemicals in food, the development of advanced and suitable analytical techniques for their identification is fundamental for the advancement of food research. In this review, the state of the art of phytochemical research in food plants is described, starting from sample preparation, throughout extract clean-up and compound separation techniques, to the final analysis, considering both qualitative and quantitative investigations. In this regard, from an analytical point of view, fruit and vegetable extracts are complex matrices, which greatly benefit from the use of modern hyphenated techniques, in particular from the combination of high performance liquid chromatography separation and high resolution mass spectrometry, powerful tools which are being increasingly used in the recent years. Therefore, selected applications to real samples are presented and discussed, in particular for the analysis of phenols, polyphenols and phenolic acids. Finally, some hot points are discussed, such as waste characterization for high value-compounds recovery and the untargeted metabolomics approach.

Extraction, chemical characterization and antioxidant activity of Litchi chinensis Sonn. and Avena sativa L. seeds extracts obtained from pressurized n-butane

The extraction of litchi (Litchi chinensis Sonn.) and oat (Avena sativa L.) seeds were investigated using n-butane as pressurized solvent by evaluating the effect of pressure in the range of 7-100 bar and temperature from 25 to 70 °C on the extract yield and chemical composition together with the antioxidant activity of the extracts obtained. It was experimentally observed extraction yields for both seeds up to ~3.5 wt%, with a total phenolic content around 126.4 mg GAE/100 g of extract, and an antioxidant activity up to 78.36%. Oat seeds extract presented higher values of these parameters evaluated compared to litchi extract. Based on the results found, it seems that n-butane may be a promising solvent to conventional extraction methods, as mild operating conditions and eco-friendly solvent can be used to provide good results without any residues in the final product.

Effect of polymorphisms in the CD36 and STAT3 genes on different dietary interventions among patients with coronary artery disease: study protocol for a randomized controlled trial

BACKGROUND

Cardiovascular disease has become a major health problem, and it has been associated with both environmental and genetic factors. Studies have shown that the Mediterranean Diet (MeDiet), or its components such as nuts and olive oil, may be strongly associated with the improvement of cardiovascular risk factors in specific populations. The purpose of the GENUTRI study is to investigate the interaction of genetics with cardiovascular risk factors in a non-Mediterranean population with coronary artery disease (CAD) according to three different diets: rich in pecan nuts, in extra-virgin olive oil or a control diet.

METHODS/DESIGN

The GENUTRI study is a single-center, randomized, open-label, parallel-group, 12-week pragmatic clinical trial conducted in patients aged 40 to 80 years and diagnosed with CAD. A standardized questionnaire will be applied to data collection and a blood sample will be obtained for lipid, glycemic and inflammatory profile evaluation. Polymorphisms in the CD36 and STAT3 genes will be detected using the TaqMan® SNP Genotyping Assay. Patients will be allocated in three groups: group 1: 30 g/day of pecan nuts; group 2: 30 ml/day of olive oil; and group 3: control diet. The primary outcome will consist of changes in LDL-cholesterol (in mg/dl) after 12 weeks of intervention.

DISCUSSION

Studies have shown the beneficial effects of diets rich in nuts and olive oil mainly in the Mediterranean population. GENUTRI is a clinical trial focusing on the effects of nuts or olive oil supplementation in Brazilian individuals. Additionally, we will try to demonstrate that genetic polymorphisms linked to cardiovascular disease may modulate the effects of different diets on biochemical and inflammatory markers among these subjects.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02202265 (registered on 18 July 2014: first version).

Olive oil authenticity studies by target and nontarget LC-QTOF-MS combined with advanced chemometric techniques

Food analysis is continuously requiring the development of more robust, efficient, and cost-effective food authentication analytical methods to guarantee the safety, quality, and traceability of food commodities with respect to legislation and consumer demands. Hence, a novel reversed-phase ultra high performance liquid chromatography-electrospray ionization quadrupole time of flight tandem mass spectrometry analytical method was developed that uses target, suspect, and nontarget screening strategies coupled with advanced chemometric tools for the investigation of the authenticity of extra virgin olive oil. The proposed method was successfully applied in real olive oil samples for the identification of markers responsible for the sensory profile. The proposed target analytical method includes the determination of 14 phenolic compounds and demonstrated low limits of detection ranging from 0.015 μg mL^-1 (apigenin) to 0.039 μg mL^-1 (vanillin) and adequate recoveries (96-107 %). A suspect list of 60 relevant compounds was compiled, and suspect screening was then applied to all the samples. Semiquantitation of the suspect compounds was performed with the calibration curves of target compounds having similar structures. Then, a nontarget screening workflow was applied with the aim to identify additional compounds so as to differentiate extra virgin olive oils from defective olive oils. Robust classification-based models were built with the use of supervised discrimination techniques, partial least squares-discriminant analysis and counterpropagation artificial neural networks, for the classification of olive oils into extra virgin olive oils or defective olive oils. Variable importance in projection scores were calculated to select the most significant features that affect the discrimination. Overall, 51 compounds were identified and suggested as markers, among which 14, 26, and 11 compounds were identified by target, suspect, and nontarget screening respectively. Retrospective analysis was also performed and identified 19 free fatty acids. Graphical Abstract Development of a novel RP-LC-ESI-QTOFMS analytical method employing target, suspect and non-target screening strategies coupled to advanced chemometric tools for the investigation of markers responsible for the sensory profile of extra virgin olive oil and guarantee authenticity.