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Flavor Components of Olive oil—A Review
Abstract and Figures
The unique and delicate flavor of olive oil is attributed to a number of volatile components. Aldehydes, alcohols, esters,
hydrocarbons, ketones, furans, and other compounds have been quantitated and identified by gas chromatography-mass spectrometry
in good-quality olive oil. The presence of flavor compounds in olive oil is closely related to its sensory quality. Hexanal,
trans-2-hexenal, 1-hexanol, and 3-methylbutan-1-ol are the major volatile compounds of olive oil. Volatile flavor compounds are
formed in the olive fruit through an enzymatic process. Olive cultivar, origin, maturity stage of fruit, storage conditions
of fruit, and olive fruit processing influence the flavor components of olive oil and therefore its taste and aroma. The components
octanal, nonala, and 2-hexenal, as well as the volatile alcohols propanol, amyl alcohols, 2-hexenol, 2-hexanol, and heptanol,
characterize the olive cultivar. There are some slight changes in the flavor components in olive oil obtained from the same
oil cultivar grown in different areas. The highest concentration of volatile components appears at the optimal maturity stage
of fruit. During storage of olive fruit, volatile flavor components, such as aldehydes and esters, decrease. Phenolic compounds
also have a significant effect on olive oil flavor. There is a good correlation between aroma and flavor of olive oil and
its polyphenol content. Hydroxytyrosol, tyrosol, caffeic acid, coumaric acid, and p-hydroxybenzoic acid influence mostly the sensory characteristics of olive oil. Hydroxytyrosol is present in good-quality
olive oil, while tyrosol and some phenolic acids are found in olive oil of poor quality. Various off-flavor compounds are
formed by oxidation, which may be initiated in the olive fruit. Pentanal, hexanal, octanal, and nonanal are the major compounds
formed in oxidized olive oil, but 2-pentenal and 2-heptenal are mainly responsible for the off-flavor.
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... The aldehyde and ester levels in the olives, which bestow a pleasant aroma, reduce when olives are stored. VCs that cause bad odors are produced when olives or oil are stored for an extended time [12,20]. C 5 VCs have a sensory behavior quite similar to that of C 6 VCs. ...
... Since small amounts of these alcohols may occur during the ripen-344 ing of olives, low levels of methanol and ethanol are acceptable. Especially, ethanol has 345 also been detected in low concentrations [12,36,37,47]. On the other hand, significant 346 amounts of ethanol are produced during the fermentation processes, which primarily oc-347 cur during the storage of olive fruit [48,49]. ...
... Since small amounts of these alcohols may occur during the ripening of olives, low levels of methanol and ethanol are acceptable. Especially, ethanol has also been detected in low concentrations [12,36,37,47]. On the other hand, significant amounts of ethanol are produced during the fermentation processes, which primarily occur during the storage of olive fruit [48,49]. ...
In this study, an alternative debittering technique for olives, invented and patented by Prof. Vassilis Dourtoglou, was employed. Olive fruits (Olea europaea cv. Megaritiki) were stored under CO2 atmosphere immediately after harvest for a period of 15 days. After the treatment, a sensory evaluation between the olives stored under CO2 and those stored under regular atmospheric conditions (control) was performed. Additionally, the CO2-treated olives were used for the cold press of olive oil production. The volatile profile of the olive oil produced was analyzed using headspace solid-phase microextraction (HS-SPME) and gas chromatography coupled to mass spectrometry (GC-MS). A total of thirty different volatile compounds were detected. The volatile characteristics of olive oil are attributed, among others, to aldehydes, alcohols, esters, hydrocarbons, alkanes, and terpenes. The volatile compounds’ analysis showed many differences between the two treatments. In order to compare the volatile profile, commercial olive oil was also used (produced from olives from the same olive grove with a conventional process in an industrial olive mill). The antioxidant activity, the content of bioactive compounds (polyphenols, α-tocopherol, carotenoids, and chlorophylls), and the fatty acids’ profile were also determined. The results showed that the oil produced from CO2-treated olives contains different volatile components, which bestow a unique flavor and aroma to the oil. Moreover, this oil was found comparable to extra virgin olive oil, according to its physicochemical characteristics. Finally, the enhanced content in antioxidant compounds (i.e., polyphenols) not only rendered the oil more stable against oxidation but also better for human health. The overall quality of the olive oil was enhanced and, as such, this procedure holds great promise for future developments.
... Phenolic compounds in several edible oils have been reported and most of these studies are limited to assessing phenolic compounds in a particular oil (Mannino et al., 1999;Tripoli et al., 2005;Siger et al., 2008;Janu et al., 2013). Among them, a vast majority of research has been focused on the phe-nolic fraction of olive oil (Kiritsakis, 1998;Ryan and Robards, 1998;Boskou et al., 2005;Galvano et al., 2007;Servili et al., 2009). In addition to the studies on the phenolic compounds in specific edible oils, a recent report has comprehensively reviewed the different classes of phenolic compounds in several edible oils (Zeb, 2021). ...
... The phenolic compounds in both olive oil and coconut oil are responsible for beneficial health effects (Covas et al., 2006;Seneviratne and Jayathilaka, 2015;Narayanankutty et al., 2018;Deen et al., 2021). The aroma and flavor of olive oil correlate with the phenol content (Kiritsakis, 1998;Genovese et al., 2018;Pedan et al., 2019). Even though the sensory properties of virgin coconut oil have been studied (Villarino, Dy andLizada, 2007, Lukic et al., 2017;Fiorini et al., 2018), the correlation between phenolic compounds and sensory properties in coconut oil needs further research. ...
The total phenol content (TPC) in coconut oil varies with extraction method, variety, nature of coconut kernel components and geographical origin. Commonly reported TPCs of coconut oils extracted by dry methods and wet methods are in the range of 70-300 mg/kg and 250-650 mg/kg, respectively. Based on the commonly reported data, the TPC of coconut oil varies by up to 527 mg/kg oil, 180 mg/kg oil, and 172 mg/kg oil due to the influence of the extraction method, coconut variety and the nature of kernel components, respectively. The identity of the phenolic compounds also varies with the extraction method. Caffeic acid, catechin, p-coumaric acid, ferulic acid, and syringic acid are present in different quantities in coconut oil when extracted by all methods. However, chlorogenic acid, cinnamic acid, epigallocatechin, gallic acid, vanillic and epicatechin are present only in some coconut oils. Many free phenolic compounds present in olive oil are also present in coconut oil.
... Five additional alcohols were generated in the Ulva sp. suspension after SC fermentation, such as 1-pentanol (fermented, oily, sweet) and 1-hexanol (fruity, floral aromatic) [20,23]. In the metabolism of brewing yeast, the Ehrlich pathway is a metabolic route to produce high alcohol content from amino acids, involving transamination, decarboxylation, and reduction [24]. ...
Seaweeds have a variety of biological activities, and their aromatic characteristics could play an important role in consumer acceptance. Here, changes in aroma compounds were monitored during microbial fermentation, and those most likely to affect sensory perception were identified. Ulva sp. and Laminaria sp. were fermented and generally recognized as safe microorganisms, and the profile of volatile compounds in the fermented seaweeds was investigated using headspace solid-phase microextraction with gas chromatography–mass spectrometry. Volatile compounds, including ketones, aldehydes, alcohols, and acids, were identified during seaweed fermentation. Compared with lactic acid bacteria fermentation, Bacillus subtilis fermentation could enhance the total ketone amount in seaweeds. Saccharomyces cerevisiae fermentation could also enhance the alcohol content in seaweeds. Principal component analysis of volatile compounds revealed that fermenting seaweeds with B. subtilis or S. cerevisiae could reduce aldehyde contents and boost ketone and alcohol contents, respectively, as expected. The odor of the fermented seaweeds was described by using GC–olfactometry, and B. subtilis and S. cerevisiae fermentations could enhance pleasant odors and reduce unpleasant odors. These results can support the capability of fermentation to improve the aromatic profile of seaweeds.
... The volatile organic compounds (VOCs) that contribute to taste and flavor belong to several chemical classes, namely aldehydes, alcohols, hydrocarbons, ethers, esters, carboxylic acids, and ketones [28]. Those most responsible for the off-flavors in olive oils are aldehydes, ketones, and alcohols. ...
The degradation process of virgin olive oil (VOO) is related to storage time and the type of storage container used. The aim of this work is to explore the evolution of the VOO quality stored in different container types over a defined storage period in order to predict the organoleptic characteristics using a non-destructive technique such as the electronic-nose (E-nose). The “Picual” variety VOO was stored in different containers over a period of 21 months and monitored using sensory analysis, volatile compounds, and an E-nose. The panelists showed that oil stored in dark glass bottles and in green polyethylene bottles began to show defects after 12 and 15 weeks, respectively. However, oil stored in tin containers retained its quality throughout the 21 months studied. A total of 31 volatile compounds were identified, and the evolution of the volatile profile in the different containers during the storage period was studied. The E-nose data were able to classify oil quality by container using principal component analysis (PCA). Furthermore, the E-nose data combined with partial least squares (PLS) regression enabled the building of a predictive model to quantify sensory defect values (RCV2 = 0.92; RCV2 = 0.86), evidencing that this technique would be an appropriate screening tool to support a sensory panel.
... According to Kiritsakis et al. [33], hexanal, (E)-2-hexenal and 1-hexanol are the major volatile compounds of olive oil, which is in agreement with our results. 2,4-Hexadienal and nonanal are among the aldehydes identified and have been associated with the oxidative status of EVOO [12]. ...
Extra virgin olive oil (EVOO) is highly appreciated by consumers for its unique sensory characteristics that are directly related to its volatile composition. The objective of this study was to investigate the effect of cultivar and geographical origin on the volatile composition of Greek monovarietal EVOOs. Samples of three local cultivars (Koroneiki, Kolovi and Adramytini) originating from three areas of Greece (Crete, Lesvos and the Peloponnese), spanning two consecutive harvesting periods, were selected. Their volatile components were determined using headspace solid-phase microextraction combined with gas chromatography–mass spectrometry. More than 70 volatile compounds were identified. Alcohols were the dominant class (43–50%), followed by ketones (12–24%), esters (12–18%) and aldehydes (4–12%). The most prominent volatile compounds were (Z)-3-hexen-1-ol (6–11%), 1-penten-3-ol (7–11%), (E)-3-hexenyl acetate (0.5–11%) and 3-pentanone (8–16%). Significant differences were observed and highlighted. Clear separations between samples from different cultivars and geographic provenances were achieved using multivariate analysis and the most discriminating volatiles were identified. Additionally, using multivariate receiver operating characteristic (ROC) curve analysis, a combination of five chemical markers was found superior (area under the curve, AUC: 1.00; predictive accuracy: 100%) for the correct classification of Koroneiki EVOOs according to geographical origin.
... As fresh olives can be easily spoiled due to high water activity until processing, they must undergo treatment in brines or be used for oil production. [1][2][3][4][5][6] In brine treatment, the main component is sodium chloride (NaCl) which is responsible for the preservative, flavoring, and delaying the action of unwanted microorganisms' development. Despite this, NaCl excess in the diet can cause cardiovascular and kidney diseases. ...
The simultaneous diffusion of inorganic components in the olive pulp in wet brine was modeled based on Fick’s generalized 2nd Law and simulated using the finite element method. The main and crossed diffusion coefficients, the film coefficient and the Biot number were determined, with the application of the simplex optimization method, through the minimization of the percentage errors. The errors between the simulated and experimental data were 5.35% for NaCl and 4.77% for KCl and the adjusted main diffusion coefficients were 0.4358 × 10-12 m2 s-1 for NaCl and 0.5408 × 10-12 m2 s-1 for KCl. The system developed to simulate diffusion allows the control and modulation of the salts content that diffuses through the olive pulp.
... Another lipoxygenase derived volatile was 2,4-hexadienal, having a fatty, sweet, green odor. Nonanal, a typical oxidation marker with a waxy odor and associated with sensory defects, was almost absent in all the oil samples [32,33]. Its absence in the two EVOO oils was due to their good quality, while the absence in olive oil was probably imputable to the deodorization carried out during refining. ...
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.
... The volatile fraction Is a class of compounds with a low molecular weight (less than 300 Da) and high vapor pressure at room temperature. They are formed by cell destruction, so an enzymatic process involves hydrolysis and oxidation that proceed at a high rate depending on the pH and temperature [12]. In olive oils, many volatiles originated from the enzymatic pathways inside olives during extraction [10], mainly produced by the oxidation of fatty acids [1]. ...
The volatile profile of an olive oil is a crucial attribute indicating its sensory quality. Hence, to elucidate the impact of geographical origin (including edaphoclimatic conditions) and the crop season on the volatile composition of monovarietal Moroccan olive oil “Picholine Marocaine”, over a two-year harvest period (2018/19 and 2019/20), thirty-eight olive oil samples were obtained from nineteen Moroccan areas well-known by the abundance of olive tree cultivation. By using SPME/GC-FID-MS, 229 and 215 volatile compounds were characterized in olive oils produced during the 2018/19 and 2019/20 crop years, respectively. The identified compounds belong to nine volatile groups: terpenes, hydrocarbons, furans, esters, alcohols, acids, ketones, aldehydes, and nitrogen compounds. The one-way ANOVA and interactive heatmap revealed significant differences in the volatiles proportion in oils from different geographical origins. Our results imply that environmental (edaphoclimatic) conditions considerably influence the volatile compounds’ biosynthesis, e.g., when soil granulometry decreases (from sand to silt), alcohols become esters due to the activity of alcohol dehydrogenase (ADH) and alcohol acetyl transferase (AAT) enzymes. Moreover, our findings exhibit a significant influence of the crop season on the volatile composition of Moroccan olive oils.
... Oils that are saturated are more stable than oils that are unsaturated (Reda 2004). Unsaturated fatty acids are the primary precursors of the volatile chemicals found in oxidized oils (Morales et al. 1997;Kiritsakis 1998). Linolenic acid is an important unsaturated fatty acid that is rapidly lost during the frying process, altering the balance of saturated and unsaturated fatty acids in the frying oil and increasing the production of off-flavors (Fellows 2009;Solinas et al. 1984). ...
Fats are important for humans, animals, and plants because of their high energy content, which accounts for large amount of energy storage in the smallest amount of food material. Fats enable humans and animals to absorb fat-soluble vitamins as well as provide essential fatty acids, which their bodies seem unable to synthesize. Since, fat in food is almost entirely reabsorbed by the body, fat as a food has a very high efficiency. Many dishes benefit from fats because they give them a smooth, creamy consistency, which results in a pleasant mouthfeel. Fats and oils have numerous applications in food such as in snack foods, milk products, bakery and confectionary products owing to different physical and sensory characteristics of these products. During processing oils and fats undergo various physico-chemical modifications which define the characteristics of the product. This chapter deals with basic understanding of fats, utility of fats and oils in different food products and modification in fats during processing.
With increasing global health and wellness product needs, pecan oil is getting popular in recent years. Although considered a gourmet oil because of its unique sensory and nutritional values, there is no publication focusing on consumer attitude toward pecan oil. This study, for the first time, investigated consumer acceptance, sensory quality, and emotional response to five pecan oils from native and improved varieties, with a comparison to an olive oil. All five pecan oils had positive hedonic ratings (>5, with a 9‐point hedonic scale) for overall acceptance and the acceptance of oil flavor, raw‐nut flavor, and thickness, while the olive oil was rated slightly lower than 5 for these attributes. Pecan oils had higher intensities in raw‐nut flavor, but lower in overall oil flavor, fatty flavor, astringency, and thickness compared to olive oil. Off‐flavor was not perceived in pecan oils, whereas it was perceived in olive oil. The six oils did not show significant differences in satiating effects; however, olive oil was rated lower in energizing effects than pecan oils, which showed a significant variety difference (p ≤ 0.05). Consumer overall acceptance was significantly, positively driven by energizing effects, followed by the acceptability of raw‐nut flavor, thickness, and oil flavor; off‐flavors were negative drivers. Results obtained from this study add direct pecan oil consumer insight: an asset for pecan growers, pecan processing industry, and pecan oil marketers.
This paper presents the procedure and the results showing the organoleptic importance of the polyphenols and volatiles compounds. The original technique developed involves (1) the isolation and identification of volatile components by enrichment of “headspace” vapors on porous polymer (Tenax GC traps), their displacement and introduction through a closed system to the GC column (Bertuccioli et al. ) coupled with MS and their quantitative evaluation; (2) the isolation and identification of the polyphenols by methanol-water mixture extraction and their evaluation by different techniques (TLC, calorimetric analysis). The evaluation of different compounds was carried out on the course of the olive oil fruits maturity and ripeness, examining also the influence of pigmentation. The results were undertaken to establish relationship between volatiles, which the GC-Sniff evaluation had determined to be “aroma significant, vs polyphenol levels, and intensity ratings of the aroma attributes. The importance of the ripeness, pigmentation rating, and oil extraction process on the major components of oil aroma are illustrated. The causes of the fluctuations in relative amounts of individual groups of constituents are discussed on the basis of possible pathways of products present in oil.
Some alkylphenols have previously been identified in concentrated steam distillates of olive oils by gas chromatography-mass spectrometry. In such analyses of unacceptable olive oils, the compounds found included cinnamic acid ethyl ester, 4-vinylphenol and styrene. 4-Vinylphenol is probably derived from p-coumaric acid by decarboxylation during storage of olives. Other compounds identified from their mass spectra were guaiacol and dimethoxybenzene.
The potent odorants of two Greek virgin olive olis differing in flavor were evaluated by aroma extract dilution analysis (AEDA) and quantitated by stable isotope dilution assay (SIDA). The odor activity values (OAVs) of these potent odorants were calculated by dividing their concentrations in the oil samples by the corresponding flavor threshold values, as an approach to objectify the flavor differences of the olive oils. Compounds which mainly contributed to several flavor notes were: hexanal and (Z)-3-hexenal (green), octanal, (Z)-2-nonenal, (E,E)-2,4-decadienal and 1-octen-3-one (rancid), ethyl 2-methyl-butanoate, ethyl 2-methylpropanoate and ethyl cyclohexanoate (fruity).
The polar volatile components of virgin olive oil were concentrated by codistillation with water, followed by solvent extraction and dry-column chromatography. Gas chromatographic-mass spectrometric examination of the polar concentrate yielded the identities of 77 components. Organoleptic assessment of some of these compounds indicated that several are significant contributors to olive oil aroma.