Gas Chromatography-Mass Spectrometry-Olfactometry To Control the Aroma Fingerprint of Extra Virgin Olive Oil from Three Tunisian Cultivars at Three Harvest Times

Analysis of Volatile Hydrocarbons (Pentene Dimers and Terpenes) in Extra Virgin Olive Oil: Optimization by Response Surface Methodology and Validation of HS-SPME-GC-MS Method

A head space-solid phase microextraction-gas chromatography-mass spectrometery (HS-SPME-GC-MS) method for the simultaneous analysis of pentene dimers from lipoxygenase (LOX) pathway, monoterpenes, and sesquiterpenes in extra virgin olive oil (EVOO) was proposed. A Doehlert design was performed; the conditions of the HS-SPME preconcentration step (extraction temperature, extraction time, sample amount, and desorption time) were optimized by response surface methodology, allowing defining the method operable design region. A quantitative method was set up using the multiple internal standard normalization approach: four internal standards were used, and the most suitable one was selected for area normalization of each external standard. The quantitative method was successfully validated and applied to a series of monocultivar EVOOs. This is the first paper in which a quantitative method using commercial standards has been proposed for the analysis of an important class of molecules of EVOO such as pentene dimers. The optimized method is suitable for routine analysis aimed at characterizing high quality EVOOs.

Insight into the comparison of key aroma-active compounds between camellia oils from different processing technology

Currently, the difference between key odorants of camellia oils from different processing technology (i.e., extra virgin camellia oil (EVCO), virgin camellia oil (VCO), fragrant camellia oil (FCO)) is unclear. In this study, a total of 91 odorants were identified by comprehensive two-dimensional gas chromatography and quadrupole mass spectrometry (GC × GC-qMS). The headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS) provided fingerprint information for 57 odorants distinguished between EVCO, VCO, and FCO. Moreover, 76 odorants were shown flavor dilution (FD) factors range from 1 to 729, and fruity esters (ethyl 2-hydroxypropanoate, ethyl decanoate, and ethyl phenylacetate) with FD factors ≥ 27 and odor activity values ≥ 1 are the unique odorants in EVCO. (E, E)-2,4-Heptadienal, (E, E)-2,4-nonadienal, and d-limonene are the aroma-active compounds in VCO. While furfural and 3-ethyl-2,5-dimethylpyrazine with FD factors ≥ 243 are the major contributors to roasted and nutty odor in FCO. This work provides aroma markers for quality assessment of camellia oils.

Thermal Effects on the Quality Parameters of Extra Virgin Olive Oil Using Fluorescence Spectroscopy

Extra virgin olive oil is one of the superlative due to its health benefits. In this work, the Fluorescence spectra of extra virgin olive oil (EVOO) from different olive growing regions of Pakistan and Al-Jouf region from the Kingdom of Saudi Arabia (KSA) were obtained. The emission bands depicted relative intensity variations in all non-heated and heated EVOO samples. Prominent emission bands at 385, 400, 435 and 470 nm represent oxidized products of fatty acids, bands at 520 and 673 nm has been assigned to beta carotene and chlorophyll isomers respectively. All EVOO samples collected from Al-Jouf region, KSA and from Pakistan (Loralai Baluchistan, Barani Agricultural Research Institute, Chakwal and Morgha Biodiversity Park, Rawalpindi) regions showed thermal stability. Other EVOO samples from Chaman Baluchistan and one sample from wild specie (Baluchistan) bought directly from farmers showed denatured spectra even without heating. Chemical characteristics of all EVOO samples changed significantly at 200 °C. Relatively, EVOO samples from Al-Jouf showed more thermal stability which might be due to geographical distribution, environmental effects, genetic background and processing or storage conditions. These results demonstrated fluorescence spectroscopy as a quick, cost-effective and reliable approach to assess the quality and thermal stability of EVOO. These characteristics of fluorescence spectroscopy may lead to the development of portable device for the onsite monitoring of EVOO.

Use of High-Performance Liquid Chromatography/Electrospray Ionization Mass Spectrometry for Structural Characterization of Bioactive Compounds in the Olive Root Bark and Wood of Chemlali Cultivar

This report aims to provide complete knowledge on the polyphenol composition and biological activities of the olive tree. The extraction of the root bark and wood of Olea europaea. L (Chemlali cultivar) was realized by solid-liquid ethanolic extraction, whose analysis was conducted via high-performance liquid chromatography equipped with photodiode array detection and mass spectrometry (HPLC-ESI-DAD and MS/MS). Moreover, radical scavenging and antibacterial activities were determined. The results present a total of 14 phenolic compounds belonging mainly to secoiridoid and flavonoid subclasses. Oleuropein was found to be the most abundant compound at an amount of up to 7000 mg/kg followed by ligstroside and oleuropein derivatives. In addition, we found oleocanthal at a great amount (2115 mg/kg). Higher individual polyphenolic concentrations were recorded in root wood extracts compared to bark ones, except for the flavonoid group. Likewise, the total phenolic compound contents increased in the olive root wood. This trend was reflected in biological activities. In fact, root wood extracts exert more important antioxidant and antibacterial activities than bark extracts due to their high bioactive compounds.

Volatile profile and quality characteristics of the Greek “Chondrolia Chalkidikis” virgin olive oils: effect of ripening stage

Among the various parameters affecting olive oil quality, ripening stage is one of the most important. Optimal harvest time ensuring target quality for the final product varies in relation to the effect of many intrinsic and extrinsic factors. Therefore, its determination necessitates thorough examination of each case. The present study explores the impact of six harvest times on volatile profile and quality attributes of olive oils from “Chondrolia Chalkidikis” Greek cultivar. All samples examined were classified “Virgin Olive Oils” (VOOs) according to findings of acidity, peroxide, and K values. The low values for the principal official quality indices, the high oleic acid percentages (76–78%), the high oxidative stabilities (up to 36 h induction period), and phenols content (606–290 mg/kg) were considered nutritionally promising. Total phenols, carotenoids and chlorophylls contents, as well as oxidative stability (induction period values) decreased with ripening. Harvest time had a strong impact on HS-SPME–GC–MS volatile fingerprint. Optimal volatile profiles were related to intermediate examined ripening stages. Fatty acid composition did not show remarkable trends. Chondrolia Chalkidikis VOOs perform as interesting candidates of high quality. Findings of the study may support existing databases with scientific records for Chondrolia Chalkidikis VOOs, boost their competitiveness in the global market, and encourage worldwide exploitation of VOOs from similar cultivars (table olives oriented).

Unraveling of the Aroma-Active Compounds in Virgin Camellia Oil (Camellia oleifera Abel) Using Gas Chromatography-Mass Spectrometry-Olfactometry, Aroma Recombination, and Omission Studies

Camellia oil is a popular edible oil in China as a result of its nutritional properties. However, the key odorants of camellia oil remain unclear. In this study, the volatiles of virgin camellia oil (VCO) were extracted by solvent-assisted and non-solvent-assisted methods. A total of 66 volatile compounds were identified using gas chromatography-mass spectrometry-olfactometry, with flavor dilution factors ranging from 1 to 729 via aroma extraction dilution analysis. Among them, 10 odorants were identified for the first time in VCO. Moreover, 41 volatiles were confirmed as aroma-active compounds with odor activity values greater than 1. Aroma recombination and omission studies demonstrated that aldehydes, esters, acids, and heterocyclic compounds significantly contribute to the aroma profiles of VCO. Hexanal, octanal, (E,E)-2,4-heptadienal, (E,E)-2,4-nonadienal, decyl acetate, ethyl benzoate, ethyl 2-methylbutanoate, 2-methylbutyl (Z)-2-methyl-2-butenoate, 2-methylbutanoic acid, hexanoic acid, 2-pentylfuran, and 2-methyl-3-furanthiol could impart roasted-like, nut-like, fat-like, fruit-like, grass-like, and sweat-like odors and were the key odorants in VCO. The lipoxygenase pathway was possibly responsible for the formation of key odorants in VCO. This work provides an extract aroma consistent for virgin camellia oil.

Olive oil consumption can prevent non-communicable diseases and COVID-19 : Review

The Mediterranean diet is appraised as the premier dietary regimen and its espousal is correlated with the prevention of degenerative diseases and extended longevity. The consumption of olive oil stands out as the most peculiar feature of the Mediterranean diet. Olive oil rich in various bioactive compounds like oleanolic acid, oleuropein, oleocanthal, and hydroxytyrosol is known for its anti-inflammatory as well as cardioprotective property. Recently in silico studies have indicated that phytochemicals present in olive oil are a potential candidate to act against SARS-CoV-2. Although extensive studies on olive oil and its phytochemical composition; still, some lacunas persist in understanding how the phytochemical composition of olive oil is dependent on upstream processing. The signaling pathways regulated by olive oil in the restriction of various diseases is also not clear. To answer these queries, a detailed search of research and review articles published between 1990 to 2019 were reviewed in this effect. Olive oil consumption was found to be advantageous for various chronic non-communicable diseases. Olive oil's constituents are having potent anti-inflammatory activities and thus restrict the progression of various inflammation-linked diseases ranging from arthritis to cancer. But it is also notable that the amount and nature of phytochemical composition of household olive oil are regulated by its upstream processing and the physicochemical properties of this oil can give a hint regarding the manufacturing method as well as its therapeutic. Moreover, daily uptake of olive oil should be monitored as excessive intake can cause body weight gain and change in the basal metabolic index. So, it can be concluded that olive oil consumption is beneficial for human health, and particularly for the prevention of cardiovascular diseases, breast cancer, and inflammation. The simple way of processing olive oil maintains the polyphenol constituents and provides more protection against non-communicable diseases and SARS-CoV-2.

Virgin Olive Oil Volatile Compounds: Composition, Sensory Characteristics, Analytical Approaches, Quality Control, and Authentication

Volatile organic compounds strongly contribute to both the positive and negative sensory attributes of virgin olive oil, and more and more studies have been published in recent years focusing on several aspects regarding these molecules. This Review is aimed at giving an overview on the state of the art about the virgin olive oil volatile compounds. Particular emphasis was given to the composition of the volatile fraction, the analytical issues and approaches for analysis, the sensory characteristics and interaction with phenolic compounds, and the approaches for supporting the Panel Test in virgin olive oil classification and in authentication of the botanical and geographic origin based on volatile compounds. A pair of detailed tables with a total of approximately 700 volatiles identified or tentatively identified to date and tables dealing with analytical procedures, sensory characteristics of volatiles, and specific chemometric approaches for quality assessment are also provided.

GC-MS analysis of e-cigarette refill solutions: A comparison of flavoring composition between flavor categories

OBJECTIVES

Electronic cigarette refill solutions (e-liquids) are available in various flavor descriptions that can be categorized as fruit, tobacco, and more. Flavors increase sensory appeal, thereby stimulating e-cigarette use, and flavoring ingredients can contribute to e-cigarette toxicity. We aim to inform toxicologists, sensory scientists, and regulators by determining flavoring compounds in e-liquids with various flavors, and compare results between flavor categories.

METHODS

Gas chromatography - mass spectrometry (GC-MS) was used to identify 79 flavorings in 320 e-liquids, classified in 15 flavor categories. Ten flavorings highly prevalent in e-liquids according to information from manufacturers were quantified. Flavoring prevalence was defined as the number of e-liquids with the flavoring as percentage of the total number of e-liquids. The method was validated in terms of specificity, linearity, repeatability, recovery, and sensitivity.

RESULTS

The mean number of flavorings per e-liquid was 6 ± 4. Flavoring prevalence was highest for vanillin (creamy/vanilla flavor), ethyl butyrate (ethereal/fruity), and cis-3-hexenol (fresh/green). Based on similarities in flavoring prevalence, four clusters of categories were distinguished: (1) fruit, candy, alcohol, beverages; (2) dessert, coffee/tea, nuts, sweets; (3) menthol/mint; and (4) spices, tobacco, and unflavored. Categories from cluster 4 generally had less flavorings per e-liquid than fruit, candy, alcohol, beverages (cluster 1) and dessert (cluster 2) (p < 0.05). Flavoring concentrations varied between e-liquids within the categories.

CONCLUSIONS

We evaluated flavoring compositions of 320 e-liquids using a simple GC-MS method. Flavoring prevalence was similar within four clusters of typically fresh/sweet, warm/sweet, fresh/cooling, and non-sweet flavor categories. To compare flavoring concentrations between individual flavor categories, additional research is needed.

Comparison of the Novel Thin Film-Solid Phase Microextraction and Sorptive Extraction Methods for Picual and Hojiblanca Olive Oil Volatile Fraction Analysis in Headspace

For first time, the new device named thin film solid phase microextraction (TF-SPME) has been used to determine the volatile profile of the Picual and Hojiblanca varieties of extra virgin olive oils. To this end, different traditional sampling methods such as headspace sorptive extraction (HSSE) with polydimethylsiloxane (PDMS) and polyethyleneglycol-modified silicone (EG/Silicone) Twisters^® have been compared with the TF-SPME devices coated with different extraction polymeric phases. PARADISe software was used as a non-targeting method to process all data. The best results were obtained by HSSE-PDMS and 2TF-SPME. Moreover, the 2TF-SPME extraction method achieved the most adequate results of linearity for most compounds, according to F-values, while the intermediate precision results were similar for both 2TF-SPME and HSSE-PDMS sampling methods. Different sensitivity was observed between both sampling methods depending on the volatile compound, without being clearly influenced by the polarity of them. Although both sampling methods enabled the main active aroma of olive oil to be determined and for them to be differentiated according to olive variety, the 2TF-SPME method appears to be the most suitable for this goal.

From Extra Virgin Olive Oil to Refined Products: Intensity and Balance Shifts of the Volatile Compounds versus Odor

To explore relationships between the volatile organic compounds (VOCs) of different grades of olive oils (OOs) (extra virgin olive oil (EVOO), refined olive oil (ROO), and pomace olive oil (POO)) and odor quality, VOCs were measured in the headspace of the oils by proton transfer reaction quadrupole ion guide time-of-flight mass spectrometry. The concentrations of most VOCs differed significantly between the grades (EVOO > ROO > POO), whereas the abundance of m/z 47.012 (formic acid), m/z 49.016 (fragments), m/z 49.027 (fragments), and m/z 115.111 (heptanal/heptanone) increased in that order. Although the refined oils had considerably lower VOC abundance, the extent of the decline varied with the VOCs. This results in differences in VOCs proportions. The high VOC abundance in the EVOO headspace in comparison to ROO and POO results in a richer and more complex odor. The identified C5–C6 compounds are expected to contribute mainly to the green odor notes, while the identified C1–C4 and C7–C15 are mainly responsible for odor defects of OOs. Current results reveal that processing strongly affects both the quantitative and relative abundance of the VOCs and, therefore, the odor quality of the various grades of OOs.

Quality Control of Psoralea corylifolia L. Based on High-Speed Countercurrent Chromatographic Fingerprinting

Traditional Chinese medicine (TCM)has played an important role in promoting the health of Chinese people. The TCM Psoralea corylifolia L. has been used in the treatment of various kinds of diseases including enuresis, vitiligo, and calvities. However, therapeutic effects of P. corylifolia L. have often influenced by the quality of plants. So, it is very important to control the quality of P. corylifolia L. In this study, analytical high-speed countercurrent chromatography (HSCCC) was successfully used to fingerprint P. corylifolia L. Samples of P. corylifolia L. were extracted by ultrasonic extraction. n-hexane-ethyl acetate–methanol–water at a ratio of 5:5.5:6.5:5 (v/v) was selected as a two-phase solvent system and the condition of HSCCC were optimized in order to good separation. And the method of HSCCC was verified (reproducibility, precision, and stability). HSCCC chromatograms exhibited six common peaks, which were selected as indicator compounds for the quality control of P. corylifolia L. Within 20 types of medicinal materials, chemical components are similar, but the levels of components are quite different in HSCCC fingerprint. The present results demonstrate that the HSCCC method provides a reliable basis for the quality control of P. corylifolia L. and can also be applied to confirm the authenticity of plant materials.

Comparative Analysis of Volatiles of 15 Brands of Extra-Virgin Olive Oils Using Solid-Phase Micro-Extraction and Solvent-Assisted Flavor Evaporation

Aroma profiles, key aroma compound quantification, and cluster analysis of 15 brands of extra-virgin olive oils (EVOOs) from three countries (Spain, Italy, and Greece) were investigated in the current study. Aroma compounds were isolated from the oil by using solvent-assisted flavor evaporation (SAFE) and solid-phase micro-extraction (SPME) and analyzed by gas chromatography-olfactometry mass spectrometry (GC-MS/O). A total of 89 compounds were screened by SPME/SAFE-GC-MS/O with chromatographic columns in 15 brands of samples. Eighty and 54 compounds were respectively identified by SPME- and SAFE-GC-MS/O. Of those, 44 compounds were detected by both methods. Undecanol, (Z)-4-decenal, (E)-2-dodecenal, and 2-nonanone extracted by SAFE were not found in EVOOs before. Eight classes of aroma compounds were identified, including 17 alcohols, 22 aldehydes, 9 ketones, 4 acids, 14 esters, 5 aromatics, 12 alkene, and 6 others. Eleven compounds were identified as the key aroma compounds in alternative brands of EVOOs by SAFE-aroma extract dilution analysis (AEDA). Hexanal, (E)-2-hexenal, (E)-3-hexenol, acetic acid, and (E)-2-heptenal were the common key aroma compounds by AEDA and odor activity values (OAVs). From the cluster analysis of the heatmap, the aroma compounds of all the Spain EVOOs were similar, and there were some differences from the samples of Italy and Greece. It suggested that both the amount and concentration of aroma compounds determine the similarity of aroma in EVOOs.

Comparison of flavour fingerprint, electronic nose and multivariate analysis for discrimination of extra virgin olive oils

Flavour is a special way to discriminate extra virgin olive oils (EVOOs) from other aroma plant oils. In this study, different ratios (5, 10, 15, 20, 30, 50, 70 and 100%) of peanut oil (PO), corn oil (CO) and sunflower seed oil (SO) were discriminated from raw EVOO using flavour fingerprint, electronic nose and multivariate analysis. Fifteen different samples of EVOO were selected to establish the flavour fingerprint based on eight common peaks in solid-phase microextraction-gas chromatography-mass spectrometry corresponding to 4-methyl-2-pentanol, (E)-2-hexenal, 1-tridecene, hexyl acetate, (Z)-3-hexenyl acetate, (E)-2-heptenal, nonanal and α-farnesene. Partial least square discrimination analysis (PLS-DA) was used to differentiate EVOOs and mixed oils containing more than 20% of PO, CO and SO. Furthermore, better discrimination efficiency was observed in PLS-DA than PCA (70% of CO and SO), which was equivalent to the correlation coefficient method of the fingerprint (20% of PO, CO and SO). The electronic nose was able to differentiate oil samples from samples containing 5% mixture. The discrimination method was selected based on the actual requirements of quality control.

Characterization of Carbonyl-Phenol Adducts Produced by Food Phenolic Trapping of 4-Hydroxy-2-hexenal and 4-Hydroxy-2-nonenal

4-Hydroxy-2-alkenals disappear in the presence of food phenolics (i.e., cathechin or quercetin), and the corresponding carbonyl-phenol adducts are produced. In an attempt to identify structure(s) of formed adducts, the reactions between model phenolics (resorcinol, 2-methylresorcinol, orcinol, and 2,5-dimethylresorcinol) and hydroxyalkenals (4-hydroxy-2-hexenal and 4-hydroxy-2-nonenal) were studied and the produced adducts were isolated by column chromatography and unambiguously characterized by one- and two-dimensional nuclear magnetic resonance and mass spectrometry as dihydrobenzofuranols (1), chromane-2,7-diols (2), and 2 H-chromen-7-ols (3). These compounds were mainly produced at slightly basic pH values and moderate temperatures. Their activation energies ( E_a) of formation were ∼25 kJ mol^-1 for adducts 1, ∼32 kJ mol^-1 for adducts 2, and ∼38 kJ mol^-1 for adducts 3. A reaction pathway that explains their formation is proposed. All of these results confirm that, analogously to other lipid-derived carbonyl compounds, phenolics can trap 4-hydroxy-2-alkenals in an efficient way. Obtained results provide the basis for the potential detection of carbonyl-phenol adducts derived from hydroxyalkenals in food products.