No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Effect of Preprocessing Olive Storage Conditions on Virgin Olive Oil Quality and Composition
Abstract
The quality of virgin olive oil (VOO) is intimately related to the characteristics and composition of the olive fruit at the moment of its milling. In this study, the determination of suitable olive storage conditions and feasibility of using this preprocessing operation to modulate the sensory taste of VOO are reported. Several olive batches were stored in different conditions (from monolayer up to 60 cm thickness, at 20 and 10 degrees C) for a period of up to three weeks, and the quality and composition of minor constituents, mainly phenols and volatiles, in the corresponding VOO were monitored. Cornicabra cultivar VOO obtained from drupes stored for 5 or 8 days at 20 or 10 degrees C, respectively, retained the "extra virgin" category, according to chemical quality indices, since only small increases in free acidity and peroxide values were observed, and the bitter index of this monovarietal oil was reduced by 30-40%. Storage under monolayer conditions at 10 degrees C for up to two weeks is also feasible because "off-odor" development was delayed, a 50% reduction in bitterness was obtained, and the overall good quality of the final product was preserved.
... With these changes, the waxes from the waxy layer on the outer surface of the fruit pass into the oil [16]. It has been revealed that the phenolic compounds transferred to olive oil are significantly affected by the storage time and temperature of the olive fruit [17]. Considering all these results, storage conditions and temperature of olive fruits are very important factors for obtaining high quality oil. ...
... Most of the published studies reported higher oil yields from olives stored at ambient temperature [17,37,39,41,47]. The increase in yield is associated with the ability of the fruit to continue ripening at ambient temperature, facilitating the degradation of the oil-bearing cells walls and consequently improving the extraction process [37,41,47,48]. ...
... Our results confirm these observations. Inarejos-García et al. [17] announced the rate of decrease in the concentration of phenolic compounds at 20 • C was higher than at 10 • C (40-45 %) decrease at 10 • C, 55-60 % decrease at 20 • C). In the study of Morales-Sillero et al. [58], almost 50 % reduction in 3, 4-DHPEA-EDA and p-HPEA-EDA compounds was recorded in oils obtained from cold-stored fruits. ...
... In line with the observations of Maxie, storage at 0 °C was neither recommended because of the risk of chilling injuries [3]. In the following decades, the potential to cold storage olive fruit was evaluated and confirmed by Californian [26,28], Australian [29]; Israelian [30], Italian [31][32][33][34][35], Spanish [36][37][38][39][40][41][42][43][44][45][46], Portuguese [47], Egyptian [48], Tunisian [49][50][51][52][53][54], Turkish [55], Iranian [56,57] and Croatian [58] research centers, which used most of the time the local cultivars for their experiments. ...
... Once it became clear that cold storage for more than one month resulted in problematic fruit quality and deficient oils, the maximum storage time was reduced and the observations were made within shorter intervals [29][30][31]45,46,49,[51][52][53]70]. Monitoring the amount of polyphenolic and volatile compounds in the stored oils, triggered even more precise observations for only several weeks and between days [34,[40][41][42]58]. More recently, the effect of short-term storage of less than one day is acquiring attention as a tool to modulate the aroma profile of the oil [71]. ...
... The effect of the layer thickness on the quality and the composition of the minor components was equally studied [40]. For up to 3 weeks, olive batches (ripening index of 4), were stored at 10 and 20 °C in plastic boxes (capacity of 50 kg of olives) filled in different layers, from monolayer, 10 cm, 20 cm to 60 cm thickness. ...
Cold storage of olive fruit has been the subject of study for over more than 50 years. From the 1990s on, an increasing amount of knowledge is build-up about the impact of the conservation on the physiological response of the fruit as well as on the quality of the extracted oil therefrom. This review offers a comprehensive synopsis of this research, discusses the most important influential factors and summarizes the results on the influence of the studied parameters on both the fruit and the oil. Currently, changing climatic conditions, new harvesting techniques and a more demanding consumer market are triggering the need to broaden this strict focus on conservation. A more dynamic view on the effects of temperature from the moment the fruit is harvested up to the oil extraction process, reveals the necessity to manage this crucial influential factor more diversely. An overview of how this management can take form is structured through a focus on the different phases of the postharvest processing and the widely different harvesting scales. Future prospects of research are presented based on the actual state of the art of cold storage research as well as on the necessities that come forward from a broader fruit temperature management perspective.
... In Table 3 are reported the results obtained for oil quality parameters, all the oils being classified as extra virgin. 1 Oil acidity, peroxide value, K 232 and K 270 did not change during the storage of washed and unwashed fruits in perforated boxes. These results differed from previous works, 21 probably because the storage was performed in perforated boxes of 25 kg during a shorter time and the fruits suffered less damage. ...
... This may be explained by the effect of the extra water present in the washed fruits on their partition coefficients. 22 In general, after 24 h a slight reduction in total phenol content was observed; this loss in phenols agreed with the results reported by Inarejos et al., 21 although it was lower because of the shorter storage time. Bitterness measured as K 225 showed the same behaviour as total phenols, the oils from unwashed fruit, being more bitter, achieving significant differences between the three fruit treatments. ...
... Previous works carried out at mill scale showed a decrease in the sensory attributes; however, in this experiment the hand-picked fruits, the short storage period and the use of perforated boxes may explain the differences. 10,21 Pilot plant-scale experiment During storage, the olive fruit showed an increase in ethanol content for both washed and unwashed fruits (Fig. 2). The highest increase was observed at 12 h (six times higher), then after 24 h only a slight increase was observed for both washing treatments. ...
BACKGROUND
Olives are stored for a short time after harvesting pending processing in the oil mills. Furthermore, olives are often washed prior to fruit storage. In this work we study how washing and storage affect fruit ethanol content and the effect on virgin olive oil ethanol content and quality.
RESULTS
Olive storage produced an increase in the fruit ethanol content, achieving values six times higher when storage was in silos. Washing the olives resulted in an increase in fruit ethanol content, although when washed olives were processed immediately no difference was found. The increase in fruit ethanol content during storage was reflected in higher oil ethanol concentration. Similarly, olive washing resulted in oils with higher ethanol concentration. Industrial conditions gave more important increases in oil ethanol content than that from olives processed by hand. For quality parameters all the olive oils were classified as ‘extra virgin’. In general, oils showed a slight decrease in some sensory attributes. At industrial scale after 24 h storage oils were classified as ‘virgin’ because sensory defects were found.
CONCLUSION
Olive storage should be avoided or reduced to less than 12 h; if possible, olives should not be washed before storage since this practice favors losses in sensory characteristics and the synthesis of ethanol, a precursor of ethyl esters. © 2020 Society of Chemical Industry
... It was determined that it did not change significantly depending on the fruit storage temperature in the case of both investigated cultivars. This result indicates that the accumulation of oil did not continue during fruit storage, which is in agreement with the findings of Inarejos-García et al. [37] during the storage of Cornicabra cultivar fruits at 10 °C and 20 °C for three weeks, and that of Yousfi et al. [23] in the case of Arbequina olives stored up to three weeks at 3 °C and 18 °C. Table 1. ...
... Morelló et al. [40] found that Arbequina olive oil had a decreased intensity of bitterness and pungency when produced from fruits that have been frozen on the trees. Inarejos-García et al. [37] observed a larger reduction of bitterness, determined as K225, in Cornicabra olive oil produced from fruits stored for 5 days at 20 °C compared to that obtained from olives stored at 10 °C for a week. The same authors concluded that prolonged storage could be useful for modifying the taste of oils of phenol-rich cultivars, such as Spanish Cornicabra, characterized by intense bitter taste that could affect consumers' preferences. ...
... Hachicha Hbaieb et al. [9] reported higher flavonoids content in the oils extracted from olives stored at 4 °C than at 20 °C, probably due to the accelerated process of ripening of fruits at the higher temperature. The content of flavonoids in Cornicabra oils obtained from fruits stored at 10 °C and 20 °C did not show a clear trend at the beginning of storage, probably because of their stable structure and high oxidation resistance, while an increase of particular flavonoids was determined after a prolonged storage, probably because of the destruction of the cell structure and the release of bound phenols [37]. ...
With the aim to investigate the influence of post-harvest olive fruit storage temperatures on virgin olive oil production parameters, composition and quality, Istarska bjelica (IB) and Rosinjola (RO) fruits were stored for seven days at room temperature (RT), +4 °C and −20 °C prior to oil production. Lower temperatures delayed post-harvest maturation of IB fruits. Theoretical oil content did not change depending on the storage temperature, while the highest oil yield and extractability index were obtained after storage at RT. Chlorophylls decreased in IB-RT and in IB-20. A decrease in the sensory quality of oils was detected after fruit storage at RT and −20 °C, while the refrigeration temperature of +4 °C preserved it. Regarding the content of fatty acid ethyl esters, an increase was observed in IB-RT oils. Storage at RT increased the content of waxes, while the lower temperatures partially suppressed this phenomenon. In oils of both cultivars, storage at +4 °C preserved the concentration of most phenolic compounds at a level more similar to that of the fresh oil when compared to the other two treatments. In the production conditions, when prolonged fruit storage is necessary, refrigeration seems to be the most suitable option.
... Moreover, olives can be stored in big cumuli outside the olive oil mill for periods that may range from weeks to months prior to oil extraction (KIRITSAKIS et al., 1998). During this storage period, mechanical, physical, chemical and physiological alterations occur in the fruit, which can cause the rupture of cellular structures and subsequent negative chemical and sensory changes in the oils obtained (BIASONE et al., 2012;INAREJOS-GARCÍA et al., 2010;VICHI et al., 2009). The olive fruit deteriorates rapidly due to the combined action of pathogenic microorganisms and internal processes of senescence. ...
... The degradation of fruit causes the loss of the texture of the flesh and tanning of the skin, and finally complete decomposition (GARCÍA et al., 1996). Virgin olive oils obtained from damaged olives usually present high acidity, low oxidation stability and high levels of oxidation, due to the increased peroxide value and specific extinction coefficients at 232 and 270 nm (GARCÍA et al., 1996;INAREJOS-GARCÍA et al., 2010). Moreover, the content in fatty acid ethyl esters also increases with storage time of olives due to fruit degradation (BIEDERMANN et al., 2008). ...
... In this context, herein we investigated the effects on olive oil quality of i) the olive oil immediately processed, and ii) of the olive oil and olive fruits stored for two-years following the traditional method of Gabes. Although some data have already been published on the effects of olive storage before oil extraction (BIASONE et al., 2012;INAREJOS-GARCÍA et al., 2010;VICHI et al., 2009), in the present investigation a particular interest was given to a traditional conservation procedure that the residents of Gabes (southern Tunisia) still apply to olive fruits of the Zarazi cultivar. In fact, after harvesting, olive fruits are traditionally sun-dried, and when completely dried they are stored in plastic bags at room temperature and then processed to obtain olive oil. ...
The present paper investigated how virgin olive oil quality is influenced by two different storage conditions that residents of Gabes (Southern Tunisia) usually apply to fruits of the Zarazi cultivar: long conservation as oil in glass bottles or traditional storage of olives as sun-dried fruits before processing for oil production. Even if both storage conditions are associated with strong losses in the qualitative characteristics of olive oil, the changes observed were more accentuated for oil stored for two years after its production compared to the oil obtained from olives stored by traditional methods.
... Moreover, olives can be stored in big cumuli outside the olive oil mill for periods that may range from weeks to months prior to oil extraction (KIRITSAKIS et al., 1998). During this storage period, mechanical, physical, chemical and physiological alterations occur in the fruit, which can cause the rupture of cellular structures and subsequent negative chemical and sensory changes in the oils obtained (BIASONE et al., 2012;INAREJOS-GARCÍA et al., 2010;VICHI et al., 2009). The olive fruit deteriorates rapidly due to the combined action of pathogenic microorganisms and internal processes of senescence. ...
... The degradation of fruit causes the loss of the texture of the flesh and tanning of the skin, and finally complete decomposition (GARCÍA et al., 1996). Virgin olive oils obtained from damaged olives usually present high acidity, low oxidation stability and high levels of oxidation, due to the increased peroxide value and specific extinction coefficients at 232 and 270 nm (GARCÍA et al., 1996;INAREJOS-GARCÍA et al., 2010). Moreover, the content in fatty acid ethyl esters also increases with storage time of olives due to fruit degradation (BIEDERMANN et al., 2008). ...
... In this context, herein we investigated the effects on olive oil quality of i) the olive oil immediately processed, and ii) of the olive oil and olive fruits stored for two-years following the traditional method of Gabes. Although some data have already been published on the effects of olive storage before oil extraction (BIASONE et al., 2012;INAREJOS-GARCÍA et al., 2010;VICHI et al., 2009), in the present investigation a particular interest was given to a traditional conservation procedure that the residents of Gabes (southern Tunisia) still apply to olive fruits of the Zarazi cultivar. In fact, after harvesting, olive fruits are traditionally sun-dried, and when completely dried they are stored in plastic bags at room temperature and then processed to obtain olive oil. ...
The present paper investigated how virgin olive oil quality is influenced by two different storage conditions that residents of Gabes (Southern Tunisia) usually apply to fruits of the Zarazi cultivar: long conservation as oil in glass bottles or traditional storage of olives as sun-dried fruits before processing for oil production. Even if both storage conditions are associated with strong losses in the qualitative characteristics of olive oil, the changes observed were more accentuated for oil stored for two years after its production compared to the oil obtained from olives stored by traditional methods.
... Several papers have been published on the effects of storage length and conditions on the resultant oil's quality. However, they generally examine manually picked fruit (Agar et al., 1998;Clodoveo et al., 2007;Dourtoglou et al., 2006;García et al., 1996;Kyriakidis and Dourou, 2002;Youssef et al., 2011) or give no indication of the harvest method (Inarejos-García et al., 2010;Kalua et al., 2008;Kiritsakis et al., 1998;Yousfi et al., 2009). Moreover, there is generally no indication of whether the fruit originated from rain-fed or irrigated orchards (Agar et al., 1998;Clodoveo et al., 2007;Dourtoglou et al., 2006;García et al., 1996;Inarejos-García et al., 2010;Kalua et al., 2008;Kiritsakis et al., 1998;Yousfi et al., 2009;Youssef et al., 2011), although we may speculate that those which are not indicated originated from rain-fed orchards. ...
... However, they generally examine manually picked fruit (Agar et al., 1998;Clodoveo et al., 2007;Dourtoglou et al., 2006;García et al., 1996;Kyriakidis and Dourou, 2002;Youssef et al., 2011) or give no indication of the harvest method (Inarejos-García et al., 2010;Kalua et al., 2008;Kiritsakis et al., 1998;Yousfi et al., 2009). Moreover, there is generally no indication of whether the fruit originated from rain-fed or irrigated orchards (Agar et al., 1998;Clodoveo et al., 2007;Dourtoglou et al., 2006;García et al., 1996;Inarejos-García et al., 2010;Kalua et al., 2008;Kiritsakis et al., 1998;Yousfi et al., 2009;Youssef et al., 2011), although we may speculate that those which are not indicated originated from rain-fed orchards. There are almost no such studies of fruit originating from modern, irrigated, and mechanically harvested orchards, although these are becoming more and more common in olive oil producing countries. ...
... The different cultivars responded differently to storage time: 'Barnea' appeared to have the strongest response (Fig. 1A), followed by 'Picual' (Fig. 1B) and 'Koroneiki', which provided the most stable oil (Fig. 1C). Increased storage temperature resulted in an accelerated increase in FFA, as has been reported previously (Clodoveo et al., 2007;García et al., 1996;Gutiérrez et al., 1992;Inarejos-García et al., 2010;Kiritsakis et al., 1998). ...
Most newly planted olive (Olea europaea L.) orchards are irrigated and
harvested mechanically. We assessed the effects of olive storage temperature and
duration on the resultant oil’s quality in three cultivars from modern orchards. Oil
acidity increased with storage temperature and time, most markedly in ‘Barnea’ and
least in ‘Koroneiki’. In ‘Koroneiki’, after 9 days in cool storage (4 and 10 �C), free
fatty acid (FFA) level remained constant. Polyphenol (PP) content behaved
differently among cultivars: in ‘Picual’, it was relatively invariable; in ‘Barnea’, it
decreased moderately; and in ‘Koroneiki’, it decreased sharply to half of its initial
value in 4 �Cstorage and one-sixth its initial value in room temperature storage after
23 days. Peroxide value (PV) did not increase during the storage period and did not
appear to be affected by temperature. Thus, different cultivars show different
responses to storage, and fruit originated from modern orchards are not necessarily
more sensitive to storage than those from traditional orchards.
... In detail, the perceived defects were attributable to incorrect management of the raw material: in fact, they were 67% for the fusty defect, 29% for the vinegary and only 4% for the musty defect. During prolonged olive storage duration, the drupe tissues are damaged, resulting in the secretion of fluids favoring the growth of undesirable microorganisms [17]; increased temperature can also increase drupe respiratory activity, leading to undesirable metabolic processes accelerating fruit deterioration and characterized by the fusty sensory defect [31]. The Principal Component Analysis (PCA) of the sensory data explained 91.4% of the variability and confirmed the strong influence of olive storage duration on the sensory characteristics of the oils produced ( Figure 1). ...
... The objective of this study, unlike other studies which investigated preprocessing storage as a way to modulate a positive reduction in the bitter taste of phenol-rich varieties with the aim of improving consumer acceptance [31], was to identify the criticality of the olive storage phase, highlighting its influence on the depletion of the EVOOs' chemical and sensory characteristics. ...
This work considered the influence of the duration of olive storage on the chemical and sensory properties of extra virgin olive oil. In total, 228 batches of olives collected during three successive crop seasons were sampled in seven industrial mills; information about olive batches (variety, harvest date) was collected, together with the produced oils. Four classes of storage times were considered: ≤24 h, 2–3 days, 4–6 days, ≥7 days. The oils’ quality parameters free acidity, peroxide number and K232 increased significantly as storage duration increased, while phenolic content decreased significantly, with a resulting effect on oil stability. The fatty acid composition was not affected by the olive storage period, while α-tocopherol, lutein and β-carotene content decreased as storage duration lengthened. Finally, the main positive sensory attributes (olive fruity, green notes, bitter and pungency) underwent a statistically significant reduction with the increase in storage duration, while the intensity of defects increased, suggesting that the duration of olive storage has an important effect on the quality of the final oil.
... Regarding minor compounds, the contents of natural antioxidants (phenolic compounds, tocopherols and carotenoids) decreased with storage time. This may occur at different speeds depending on the olive variety and the selected temperature (Inarejos- García, Gómez-Rico, Desamparados Salvador, & Fregapane, 2010;Yousfi et al., 2008). An increase in the storage temperature of the fruit before processing causes a deterioration in both the oxidative stability and the sensory quality of extracted oils, since both factors depend on the presence of these compounds (Tena, Wang, Aparicio-Ruiz, García-González, & Aparicio, 2015). ...
... All rights reserved. found in oils from 'Cornicabra' fruits stored at 10°C (Inarejos- García et al., 2010). Nevertheless, no significant variations were observed in terms of C6 compounds in the oils obtained from 'Chetoui' fruits, stored in similar conditions (Hachicha Hbaieb, Kotti, Gargouri, Msallem, & Vichi, 2016). ...
The suitability of the cold storage (2 °C) of fruit to maintain the quality of ‘Manzanilla de Sevilla’ and ‘Manzanilla Cacereña intended for virgin olive oil extraction was investigated.This temperature was effective in keeping the best commercial category of oil quality in both manually harvested olives and in mechanically harvested Manzanilla Cacereña fruits for 11 days. Mechanical harvesting induced significant decreases in oxidative stability, phenolic compounds content in the oils during cold storage and, only initially, in the total volatiles, regardless of the cultivar considered. However, the contents of volatile esters, associated to fruity flavor, were always higher in the oils from mechanically harvested fruits. Manzanilla de Sevilla oils exhibited higher total volatiles during fruit cold storage, regardless of the harvesting system used.
... The quality of olive oil is associated with chemical composition, oxidative stability, and sensory characteristics of the oil [3]. The chemical composition of extra virgin olive oil (EVOO) depends on the olive fruit composition [4], which changes differently in various fruit varieties [5], degree of fruit ripening [6], environmental condition [7], techniques of processing [8], and storage conditions [4]. ...
... The quality of olive oil is associated with chemical composition, oxidative stability, and sensory characteristics of the oil [3]. The chemical composition of extra virgin olive oil (EVOO) depends on the olive fruit composition [4], which changes differently in various fruit varieties [5], degree of fruit ripening [6], environmental condition [7], techniques of processing [8], and storage conditions [4]. ...
Background: The chemical composition of olive oil will change regarding to cultivar, ripening stage and edaphoclimatic regions. The effect of two edaphoclimatic regions (Fasa and Tarom), two fruit ripening stages (purple and black) and three olive cultivars (Arbequina, Koroneiki, and Roghani) were studied. Methods: Some functional physicochemical properties (fruit weight, ratio of flesh/stone weight, fruit size, oil content, fatty acid composition, and nutritional indexes) for three olive cultivars were tested. Results: The statistical results indicated that the average weight of fruit in Tarom is higher than that in Fasa. Oil content reduced during maturity period in both regions in Koroneiki (43.20 to 33.75% in Fasa and 36.91 to 34.16% in Tarom) and in Roghani of Tarom (48.97 to 42.97%), while the value increased in Roghani of Fasa (22.19 to 30.57%) and remained unchanged in other samples. The oleic acid is higher than other fatty acids in all cultivars and regions, while increased in Koroneiki of Fasa and decreased in Arbequina and Roghani of Fasa and Tarom and Koroneiki of Tarom during maturity period. The ratio of ?3/?6 during maturity period decreased in all samples except in the oil from Koroneiki of Fasa and Roghani of Tarom. The PUFA/SFA increased in the oil from Arbequina of Fasa (0.80 to 0.86) and Koroneiki (0.53 to 0.63 and 0.42 to 0.49) and Roghani (0.66 to 0.94 and 0.78 to 0.90) of Fasa and Tarom, respectively, while decreased in Arbequina of Tarom (0.71 to 0.69). Conclusion: In most samples, fruits in last ripening stage have lower content of oil, moisture, F/S ratio and oxidative stability. So, in order to produce high yield and quality olive oil, recommended that, olive fruit harvesting was done before the end of complete maturity progress, in purple stage.
... On the other hand, the progressive cell disruption during fruit storage, evidenced by pulp firmness decay and also temperaturedependent , could favor the enzymatic activity by making the substrates available. The role of LOX derived volatiles in the definition of oil quality during storage has been less studied, but they were reported to be modified as a consequence of LOX pathway enzymes activities, and to be crucial for oil sensory quality (Clodoveo et al., 2014;Inarejos-Garci´a, Gómez-Rico, Desamparados Salvador, & Fregapane, 2010;Kalua et al., 2008). ...
... Hexanal, showed a moderately decreasing trend in both varieties during storage at 4°C, in disagreement with that reported for other olive varieties (Inarejos-Garci´a et al., 2010;Kalua et al., 2008), but very similar to concentrations reached during ripening (Table 1). Conversely, storage at 25°C induced the increase of hexanal, which occurred progressively in Arbequina oils and just at the very end of the storage period in Chétoui oils (Table 1). ...
The distinctive aroma of virgin olive oil is mainly attributed to its volatile profile including components responsible for positive attributes and others for sensory defects resulting from chemical oxidation and exogenous enzymes. For this reason, the evolution of volatile compounds from Chétoui and Arbequina virgin olive oils during olive ripening and storage (at 4 and 25. °C during 4. weeks) was investigated. The profile of volatile phenols during olive storage was also studied.Quantitative differences in the volatile compounds during olive storage at 4 and 25. °C according to olive cultivar was determined.Concerning the volatile phenols, the Arbequina olives were the most affected by high storage temperature, as the formation of these compounds, especially 4-ethyl and 4-vinyl derivatives of phenol and guaiacol were more noticeable in Arbequina oils extracted from stored fruits at 25. °C.
... The method reported by Inarejos-García, Gómez-Rico, Salvador, & Fregapane [23] was used. Oil was dissolved in hexane, and then the solution was analyzed using a 1100 series Agilent Technologies High Performance Liquid Chromatograph (HPLC) equipped with a silica gel Lichrosorb Si-60-5 column (250 mm × 4.6 mm i.d., particle size 5 µm; Sugerlabor) and a fluorescence detector (Agilent Technologies 1200 series, Waldbronn, Germany) with excitation and emission wavelengths set at 290 and 330 nm, respectively. ...
Although deep frying is widely used, little is known about the effect of frying different meats on the frying oil. The aims of this study were to investigate whether the pork type influences the characteristics of the frying oil, to compare any effects with those of French fries, and to research whether the use of thermally damaged oil differentially affects those products. French fries and pork from pigs reared outdoors on acorns and grass (outdoor) or indoors on a concentrated feed (indoor) were deep-fried in either raw or previously heated olive oil. The type of product affected most color parameters, K268 and the α-tocopherol content of the oil. The frying of outdoor pork hardly affected the α-tocopherol content, whereas the frying of indoor pork and especially French fries caused a significant decrease. This suggests that the meat type should be considered when setting the frying lifespan of olive oil. Regarding the fried products, L*, moisture (only French fries) and the malondialdehyde (MDA) content (only indoor pork) were the only parameters affected by the previous oil damage. The outdoor pork was less susceptible to oxidation than the indoor pork when the oil was severely damaged. Therefore, pig outdoor-based systems based on antioxidant-rich diets might be convenient to maintain oxidation at the lowest level after frying.
... There is, however, a significant difference between the phenolic maturation and the industrial maturation of oil [84]. 3,4-DHPEA-EDA, derived from oleuropein, is responsible for the bitter taste, while p-HPEA-EDA, derived from ligstroside, is responsible for the pungent taste, both positive characteristics of olive oil [85,86]. ...
Electrochemical sensors, sensor arrays and biosensors, alongside chemometric instruments, have progressed remarkably of late, being used on a wide scale in the qualitative and quantitative evaluation of olive oil. Olive oil is a natural product of significant importance, since it is a rich source of bioactive compounds with nutritional and therapeutic properties, and its quality is important both for consumers and for distributors. This review aims at analysing the progress reported in the literature regarding the use of devices based on electrochemical (bio)sensors to evaluate the bioactive compounds in olive oil. The main advantages and limitations of these approaches on construction technique, analysed compounds, calculus models, as well as results obtained, are discussed in view of estimation of future progress related to achieving a portable, practical and rapid miniature device for analysing the quality of virgin olive oil (VOO) at different stages in the manufacturing process.
... The aliphatic six-carbon compounds like the aldehydes, alcohols, and their esters, are the most frequently found compounds in VOO aroma [78], while the major volatile compounds of olive oil, trans-2-hexenal, 1-hexanol, hexanal, and 3-methylbutan-1-ol are responsible for the fresh and lively fragrances [65]. The aroma of olive oil also depends on factors like the ripening and preprocessing of fruits and, most essentially, the genetics of the plant [79,68]. The biotechnological intervention helped to understand the role Table 3. ...
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.
... The 3,4-DHPEA-EDA, derived from oleuropein, is responsible for the bitter taste, whereas p-HPEA-EDA, derived from ligstroside, is responsible for the pungent taste [17]. Bitter and pungent are therefore positive characteristics of the EVOO as linked to health benefits, such as most of the PCs of the EVOO [18]. Biological activities of the secoiridoids consist principally in: depletion of oxidized low density lipoprotein; increase of the plasmatic antioxidant capacity; protection from inflammatory reactions [19][20][21]. ...
: This review focuses on the conditions required to increase and maintain the antioxidant nutrients in both extra virgin olive oil (EVOO) and table olives (TOs) from the agronomic and technological practices to the gastronomy. The main antioxidants of TOs and EVOO are phenol alcohols and acids, secoiridoids, lignans and flavones, all of which possess the ability to prolong the oil’s shelf-life and exhibit healthy properties for humans. The precise detection of secoiridoid derivatives remains the breakthrough for the nutritional and health quality certification of extra virgin olive oils (EVOOs) required for EFSA health claims. To attain the necessary antioxidant quality in both EVOO and TOs, it is necessary to hard focus on the several steps in the production chain, including olive cultivar, agronomic conditions, harvesting methods, and transformation technology. The quality level is maintained if the storage conditions aim to minimize the oxidative processes that occur due to oxygen and light. In terms of minor polar biophenols, there is disagreement on which between the organic or conventional EVOOs show higher concentration values. The strict disciplinary of production of protected designation EVOOs does not ensure higher phenol values in comparison to the artisanal EVOOs. In gastronomy, the EVOOs are preferable to seed oils, particularly during frying vegetable. The EVOOs show higher heat stability, linked both to the fatty acid composition and the phenol content, that is important for preventing fatty acids oxidation. Concerning TOs, the commercial presentation includes olives and olive paste. Both products show a remarkable loss of natural antioxidants after pasteurization and during storage as the thermal treatment mostly impacts on TOs secoiridoids.
... Second, regardless of its physico-chemical characteristics, it must not present sensory defects, determined by a standardized tasting procedure (European Commission, 2013). Third, in addition to requirements regarding fatty acids compo-Some authors ( Agar et al., 1999;Clodoveo et al., 2007;García et al., 1996b;García et al., 1996a;Gutierrez et al., 1992;Inarejos-Garci á et al., 2010;Kalua et al., 2008;Kiritsakis et al., 1998;Vichi et al., 2015;Yousfi et al., 2008 ) focus on compliance with upper limits of standard parameters (e.g. free acidity and peroxide value), meaning that an observed decay in quality was considered acceptable or even beneficial with respect to sensory traits. ...
The feasibility of producing extra virgin olive oil several months after the harvest season has been investigated. For this purpose, fresh olive drupes have been frozen by three different methods (i.e. blast freezer, cryogenic nitrogen, and conventional static freezer) and processed to olive oil after 6 months of storage at −25 °C temperature. The quality of the oils extracted from the frozen olive has been compared to a control olive oil produced from the corresponding fresh olive drupes, without freezing or storing, and according to the oil conventional commercial parameters (free acidity, peroxide value, UV coefficients), biophenolic and volatile profiles. The oils from frozen olive retain the commercial extra virgin grade despite a slight increment in the peroxide values, regardless the initial freezing treatment. A strong reduction of biophenols has been recorded, without significant differences imputable to the initial freez- ing method. However, the biophenolic profiles were almost unaffected, unlike the volatile profiles which undergo two main variations. First, a shift of the LOX pathway towards more oxidized compounds, such as hexanal and hexan-1-ol. Second, the occurrence of volatiles generally related to olive deterioration as response to microbial activity and/or amino acid conversion, such as butyl acetate, 3-methyl butanol and ethyl propanoate. This effect seems to be more intense when the initial freezing was performed by the conventional static freezer. An olive sanification treatment could be implemented before freezing to face this problem.
... This reduc- tion is associated with a number of additional changes also occurring in olives as a result of storage. Among them, loss of volatiles, alterations in chemical quality indices and FA composition, appearance of 'off-flavor', etc. (Inarejos-García, Gómez-Rico, Desamparados Salvador, & Fregapane, 2010;Kalua, Bedgood, Bishop, & Prenzler, 2006). For this reason, it is necessary to develop new strategies that enable olive phenolics to be preserved, particularly when delay in oil processing occurs. ...
A new strategy based on the application of phytoregulators was developed to minimize the natural degradation of antioxidants during olives storage. For that purpose, the effect of the phytoregulators abscisic acid and methyl jasmonate on olive phenolic acids was studied. In particular, four treatments were applied: abscisic acid was applied as a paste and as a spray together with low temperatures, whereas methyl jasmonate as a paste at low temperatures and as a vapor at mild temperatures. As a result, abscisic acid spray and methyl jasmonate vapor resulted in significantly higher contents of all phenolic acids. In contrast, when the phytoregulators were applied in paste form, no effect was observed. To confirm these results, the IC50 value was also determined. An increase of IC50 from 2.31 to 4.10 µg/ml after abscisic acid spray treatment and from 2.72 to 5.36 µg/ml after methyl jasmonate vapor treatment was obtained.
... It has been reported that the total phenolic content of olive oil was increased in cold pressed olives (Parenti et al., 2008). Also, oil that was obtained from olives stored at 5 to 10 °C experienced lower hydrolytic, oxidative degradation and off-odour development (Clodoveo et al., 2007;Inarejos-García et al., 2010). Therefore, amurca extract should be considered a potential natural antimicrobial for enhancing the keeping quality of foods that will be stored for extended periods at refrigerated temperatures. ...
The antimicrobial activity of a methanolic extract of amurca (olive oil lees) was determined against both Gram-positive (L. monocytogenes and S. aureus) and Gram-negative (E. coli O157:H7 and S. enteritidis) foodborne pathogens at 10 °C or 37 °C using microdilution and disk diffusion methods, and its relative activity was compared to selected antibiotics. Minimum inhibitory (MIC) and minimum bactericidal (MBC) concentrations of amurca extract ranged from 60 to 80 µl/ml at 37 °C after 24 h against all tested strains. At 10 °C, amurca was more inhibitory with MIC and MBC values of 40 and 60 µl/ml, respectively, after 7 d against tested strains. Amurca at 40 µl/ml reduced numbers of tested pathogens by 2.5 to 3.2 log10 CFU/ml at 10 °C after 7 d, but was not inhibitory at 37 °C after 24 h. Protein prepared from amurca was not antimicrobial. The relative antimicrobial activity (inhibition zone ratio) of 80 µl/mlamurca methanolic extract compared to chloramphenicol, erythromycin, gentamycin and tetracycline ranged from 0.36 to 1.0 against Gram-negative and from 0.45 to 2.0 against Gram-positive bacteria. In addition, amurca extract inhibited E. coli O157:H7 02-0628 and S. aureus 26127 which were resistant to tetracycline and chloramphenicol, respectively. © 2015, Sociedade Brasileira de Ciencia e Tecnologia de Alimentos, SBCTA. All rights reserved.
... Among post-harvest operations prior to oil extraction, storage of the olives is the step that has been most considered. In the past years, several studies have been carried out to evaluate the effect of long term storage on the quality of the olives and the oils extracted from them [2][3][4][5][6][7]. The storage periods evaluated range from 3 days to 3 weeks at temperatures from 4 to 20°C. ...
To identify critical points during olive mill pre‐processing operations, the effect of the closed circuit washing stage on olive microbiological contamination, and the influence of the successive short‐term storage on olives and virgin olive oil (VOO) quality were evaluated. Microbiological, physical, and chemical parameters were assessed in olives and oils at three mill pre‐processing stages: reception, washing, and short‐term storage. Olive washing in closed loop systems was shown to be a critical control point at the olive mill due to microbiological cross‐contamination and fruit physical damage. Moreover, when the olives were short‐term stored before oil extraction, positive VOO sensory attributes decreased by as much as one point of intensity, as justified by the changes observed in phenolic and lipoxygenase derived volatile compounds. These results confirm the high risk of fruit cross‐contamination due to the poor hygiene of the water used in olives mills to wash olives, and point out the effect on VOO quality of a common practice such as short term silo storage of olives.
Practical applications: The identification of new critical control points within pre‐processing operations in ordinary usage, and commonly accepted as good production practices, will contribute to enhance virgin olive oil quality. Preventive actions can be undertaken on the basis of the reported results, such as the control of water hygiene and short term storage conditions.
The figure shows the microbiological contamination of olives during washing with recycled water and during short‐term silo storage, and the loss of sensory quality in the correspondent virgin olive oils.
... Whereas oils extracted from stored fruits at 4°C showed a progressive increase in these compounds until 2 weeks. This changes in the desirable LOX products, in particular the C6 compounds, which are responsible for the positive aroma perceptions in olive oils, is in agreement with previous studies (Inarejos-Garci´a, Gó mez-Rico, Desamparados Salvador, & Fregapane, 2010). ...
The ability of olive endogenous enzymes β-glucosidase, polyphenol oxidase (PPO) and peroxidase (POX), to determine the phenolic profile of virgin olive oil was investigated. Olives used for oil production were stored for one month at 20 °C and 4 °C and their phenolic content and enzymatic activities were compared to those of ripening olive fruits. Phenolic and volatile profiles of the corresponding oils were also analysed. Oils obtained from fruits stored at 4 °C show similar characteristics to that of freshly harvested fruits. However, the oils obtained from fruits stored at 20 °C presented the lowest phenolic content. Concerning the enzymatic activities, results show that the β-glucosidase enzyme is the key enzyme responsible for the determination of virgin olive oil phenolic profile as the decrease in this enzyme activity after 3 weeks of storage at 20 °C was parallel to a dramatic decrease in the phenolic content of the oils.
... At this stage, it is worth mentioning that all industries have to meet legal requirements related to quality and environmental impact. For instance, all olive oil mills carry out the olive quality control and refuse the product that get fermented or rotten that could cause organoleptic problems (Mraicha et al., 2010;Inarejos-Garcia et al., 2010). As regards environmental impact, all industries have been assessed by the EIE (regulated by the R.D. 1/2008 of 11 th January, in the case of Spain) and have applied the corresponding programmes of mitigation measures and Environmental Surveillance Plan . ...
This paper studies the level of technical efficiency in the olive oil industry from a multi-output perspective, and examines olive oil production in quantitative and qualitative terms. The study also covers the environmental impact of the production process. These are key issues due to the current environmental, organoleptic and food traceability requirements of the EU Common Agricultural Policy (CAP). Furthermore, product differentiation is sought after in today's ever more demanding markets. The production of olive oil in Andalusia (Spain) is the most important agricultural food industry in the whole region and it represents 30% of world olive oil production. Three data sources have been used: a comprehensive survey to a sample of olive oil producers, their financial reports, and the opinion of a group of experts in olive oil production techniques interviewed by means of the Delphi survey. With this data and after the construction of indicators, a production frontier is elaborated by applying an extension of the Data Envelopment Analysis (DEA) technique. This will allow for the measuring of the relative technical efficiency indices and set specific efficiency indices for both the quality of the oil produced and the environmental impact of the production process. Those factors impacting on efficiency are determined by a truncated regression model with bootstrap. The results show a medium-high level of relative technical efficiency and highlight the importance of efficiency factors involving production and marketing associations.
... Olive oil is a source of at least 30 phenolic compounds (Perez-Jimenez, Neveu, Vos, & Scalbert, 2010; Rothwell et al., 2012). The phenolic composition varies greatly in quantity and quality depending on age of the tree, agricultural techniques, degree of ripeness, soil composition, climate, processing technique and storage (Amarowicz et al., 2009;Cicerale, Lucas, & Keast, 2010;Corona, Spencer, & Dessi, 2009;Inarejos-Garcia, Gomez-Rico, Desamparados Salvador, & Fregapane, 2010). Among these, the cultivar has the most significant impact on the phenolic composition of virgin olive oil (Fabiani et al., 2011), and a statistical methods based on the metabolites concentration in monovarietal olive oils was explored to recognize their origin (Cavaliere et al., 2007). ...
In this paper a new targeted metabolic profile approach using Orbitrap High Resolution Mass Spectrometry was described. For each food matrix various classes of bioactive compounds and some specific metabolites of interest were selected on the basis of the existing knowledge creating an easy-to-read fingerprinting named “FancyTiles”. The procedure resulted in a plot of semi-quantitative data allowed to highlight for each food the main metabolites related to the biological or sensorial attributes within an educated schema. Results showed that the FancyTile procedure is an useful tool for research programs aiming at improving the health potential of food and ingredients.
In this paper the FancyTile was described and it was successfully applied to verify the differences in the metabolic profile. Olive oils from different cultivars, waste mill waters from olive grown in different location and artichokes cultivated with different agronomical practices was used as case study.
... On the other hand, the attributes related to waste management (Roig et al., 2006; Evagelia et al., 2006) and noise control were the most valued ones. 1 At this stage, it is worth mentioning that all industries have to meet legal requirements related to quality and environmental impact . For instance, all olive oil mills carry out the olive quality control and refuse the product that get fermented or rotten that could cause organoleptic problems (Mraicha et al., 2010; Inarejos-García et al., 2010). As regards environmental impact, all industries have been assessed by the EIA (regulated by the R.D. 1/2008 of 11th January , in the case of Spain) and have applied the corresponding programmes of mitigation measures and Environmental Surveillance Plan (Arvanitoyannis et al., 2008).Table 2 shows descriptive statistics of the variables intervening in the frontier for the sample of the 88 olive oil mills studied, including the quality and environmental compliance indices calculated through the procedure presented above. ...
This paper studies the level of technical efficiency in the olive oil industry from a multi-output perspective, and examines olive oil production in quantitative and qualitative terms. The study also covers the environmental impact of the production process. These are key issues due to the current environmental, organoleptic and food traceability requirements of the EU Common Agricultural Policy (CAP). Furthermore, product differentiation is sought after in today’s ever more demanding markets. The production of olive oil in Andalusia (Spain) is the most important agricultural food industry in the whole region and it represents 30% of world olive oil production. Three data sources have been used: a comprehensive survey to a sample of olive oil producers, their financial reports, and the opinion of a group of experts in olive oil production techniques interviewed by means of the Delphi survey. With this data and after the construction of indicators, a production frontier is elaborated by applying an extension of the Data Envelopment Analysis (DEA) technique. This will allow for the measuring of the relative technical efficiency indices and set specific efficiency indices for both the quality of the oil produced and the environmental impact of the production process. Those factors impacting on efficiency are determined by a truncated regression model with bootstrap. The results show a medium–high level of relative technical efficiency and highlight the importance of efficiency factors involving production and marketing associations.
... This phenomenon can be explained considering that during the storage there was a transfer of these compounds from the aqueous fruit phase to the oil fruit phase, the subsequent decrease is probably due to their decomposition by polyphenol oxidase enzymatic reaction. Other authors have found that the Cornicabra cultivar virgin olive oil obtained from drupes stored for 5 or 8 days at 20 or 10 • C, respectively, have reduced levels of polyphenols (Inarejos-Garcia et al., 2010). Furthermore, it is evident; the content of polyphenols in the oil is very poor if the oil is obtained from fallen olives whose plants were irrigation with wastewater. ...
Nowadays, lots of efforts are made in Tunisia for the exploitation of wastewater in agriculture in order to face a very elevated mobilization of resources in water (90%). At Sfax, a Governorate placed in the South of Tunisia, the annual rainfall rarely exceeds 200 mm, so the climate is fairly arid. The significant water deficit can be reduced with the reuse of treated wastewater (TWW). The Sfax wastewater originated from the municipal wastewater treatment plant (WWTP) localized at 5 km in the south of Sfax, Tunisia. This WWTP is an aerated lagoon process receiving industrial wastewaters. Its treatment capacity is 24.000 m(3)/clay. Part of TWW is sent to the olive crops of El Hajeb, as part of a proposed wastewater use in agriculture. Already the wastewater is used to irrigate olive trees and intercrops such as cotton, oats and sorghum silage (Charfi et al., 1999). The aim of the present work was to determine the impact of the irrigation utilizing wastewater on the quality of the oil. The oils analysed were extracted from olives hand-picked directly from the tree and from olives that have fallen under the trees. Moreover, a study on the olive storage has been made in order to evaluate in which way the collection of the fruit could influence the quality of the oil. The results obtained showed that: Olive trees benefit from this contribution of water; irrigation by wastewater has a significant effect in the fatty acid composition; oils relative to olive trees irrigated with wastewaters are more sensible to the oxidization especially after olive storage; oils coming from olive trees irrigated with wastewaters are richer in polyphenols; oils extracted from fallen olives are of poor quality essentially after olives storage and when olive trees are irrigated by wastewater. (c) 2011 Elsevier B.V. All rights reserved.
... nal oil. This decrease in quality might be due to lower levels of E-hex-2-enal and hexanal, associated with a decrease in enzyme activity, and a concurrent increase in E- hex-2-enol, which might indicate a possible enzymatic reduction by alcohol dehydrogenase (Olias et al., 1993,Salas et al. 2000) and reduced chemical oxidation (Morales et al. 1997). Inarejos-Garcia et al. (2010 studied the olive oils from Cornicabra olives stored at different conditions (from monolayer up to 60 cm thicknesses at 10 ºC (20 days) and 20 ºC (15 days)). E-hex-2-enal showed a Gaussian-type curve trend during storage that can be related to the decrease of hydroperoxide lyase activity. C 6 alcohols showed different trends, during sto ...
In extra virgin olive oil production, the time between olive harvesting and milling is a critical period that must be carefully controlled to preserve oil quality. Particularly, several detrimental phenomena can emerge during storage. Hence, a key issue for producers is to optimize conditions to preserve the quality of fruit before milling. With this requirement in mind, we tested the effect of olive cooling and short-term cold storage on olive oil quality in two experiments. The first, baseline trial was run in the laboratory, and involved storing small batches of olives at 6°C and at 25°C for 16 h. Here, the aim was to simulate a situation with a high temperature difference. The second experiment was conducted at industrial scale, using a refrigerated storage cell. One batch of fruit was stored at 6.5°C for 16–18 h, while a control batch was stored at ambient temperature (13.5 ± 1°C). Finally, the effect of the surface/volume ratio (SVR) of the storage container was evaluated in a full factorial experiment. Although an effect of SVR on olive temperature was found, no significant differences were registered in oil quality. Short-term storage after cooling slowed metabolic processes, reducing hydrolysis of phenols and slowing the development of undesirable compounds. Furthermore, it supported oxidation, evidenced by higher concentrations of the oxidized form of polyphenols and higher production of lipoxygenase pathway compounds. The latter result suggests that this system could be successfully used to modulate the aroma profile of the produced olive oil.
This study was achieved to examine the effects of freezing olive fruits of the Arbequina, Koroneiki and Mission cultivars (the most common olive oil producing cultivars in Iran) on the standard indices used for assessing virgin olive oil quality. Oil was obtained from olive fruits stored at-4˚C for 1 week and 3 weeks, and compared with oil obtained immediately after harvest (control). The quality indices of oils obtained from frozen fruit showed no significant degradation in quality compared with the control samples. In fact the peroxide value of the frozen fruits decreased compared to the control, which is considered to have a positive effect on oil quality. In addition, compositions of the main fatty acids are not altered by freezing which demonstrate frozen storage as a viable option. Oil derived from frozen olive fruit is not of inferior quality to non-frozen fruit in the production of olive oil.
Stabilization of rice bran after milling is a necessary step to avoid subsequent oxidation of lipids in the bran. Selected moving-bed drying methods, i.e., hot-air fluidized bed drying (HAFBD), superheated-steam fluidized bed drying (SSFBD), and infrared vibrated bed drying (IRVD), were used to reduce the moisture content of the bran and, at the same time, inactivate deleterious enzymes, which are the cause of oxidation. Drying kinetics, oxidative stability parameters (i.e., lipase activity, free fatty acid content, and peroxide value), oil extraction yield, and contents of phenolic compounds and γ-oryzanol as well as color changes of the bran were determined. SSFBD could reduce the drying time by 8–22 and 76–79% in comparison with HAFBD and IRVD, respectively. Drying method significantly affected the total phenolic content (TPC) and total color changes but did not significantly affect the γ-oryzanol content of the bran. SSFBD resulted in the lowest levels of all oxidative stability parameters and to the highest TPC and oil extraction yield. SSFBD at 140°C resulted in the bran with the longest shelf life of 55 days and is suggested as an alternative method to shorten the stabilization process and maintain the stability of rice bran.
Superior quality extra virgin olive oil must be obtained from healthy and properly ripened olive fruits. Nevertheless, the production of a high quality food product requires not only an irreproachable raw material but also an ad hoc process control and quality assurance throughout the whole manufacturing process. The fine sensory characteristics and the remarkable nutritional and biological properties of this traditional Mediterranean fruit juice are mainly due to the presence of its minor components, chiefly volatile and phenolic compounds. It is known that the presence and amount of these minor components in virgin olive oil depend on agronomic practices and technological variables: the olive cultivar, the degree of ripening of the fruit, as well as the oil extraction process, in particular the milling and kneading parameters. Therefore, the use of proper manufacturing conditions during agronomic practices and processing clearly offers the chance to modify the final contents and profiles of phenolic and volatile components in the oil and therefore to modulate the properties and the sensory perceptions of the final product allowing the olive oil mill industry to design the desired type of virgin olive oil to be produced. It must be a shared responsibility between growers and producers, all of which must reach the proper requirements of an ad hoc process control and quality assurance procedures. The aim of this review is therefore to evaluate and discuss the effect of the production variables that can be easily modified by olive oil producers to modify the content and profile of minor compounds and as a consequence the properties and quality of the oil, with the goal to be able to design their own desired olive oil type.
Studies on flavor profiles of virgin olive oil (VOO) are becoming more and more numerous. The VOO aromas are determined by a mixture of chemicals in olive oil, which influence its quality. Various studies around the world have shown that the volatile compounds in VOO depend on the climate, cultivation and process. The present work is a first approach to compare volatile profiles of VOO largely produced in eastern of Morocco after 6 months of storage at ambient temperature in darkness. Oxidative stability measured by Rancimat method at 101C was also determined. VOO volatile profiles were examined using the solid-phase micro extraction fibre method (SPME) in conjunction with gas chromatography/mass spectrometer (GC/ MS). 84 volatile compounds were identified; they belong to various chemical classes, such as aldehydes, alcohols, esters, ketones, carboxylic acids and hydrocarbons. The main volatile compounds present in olive oil samples were compounds with 6 carbon atoms (C6) such as Hexanal, (E)-hex-2-enal, Z-3-Hexen-1-ol and 1-Hexanol. Ethanol and Z-3, 7-dimethyl-1, 3, 6-octatriene, methyl acetate and ethyl acetate were also found. In general, these compounds have been identified in all VOO analyzed samples. The chemical compositions of the analyzed virgin olive oil headspaces evidenced that the most representative compounds In Isly and Kenine were carboxylic acids accounted for 59.24%-49.7% respectively, whereas the volatile fraction of the oil from Achajara almoubaraka showed significantly higher amounts of the alcohols (46%). Concerning oxidative stability, Isly and Kenine OO, have lower stability values compared to Achajara almoubaraka. Their potential oxidative susceptibility is therefore much higher than Achajara almoubaraka.
The stimulation of the human sensory receptors by compounds present in virgin olive oils (VOOs) gives rise to the sensory attributes that describe its particular aroma. The sensor panel evaluation and the molecules responsible for sensory perceptions of virgin olive oil quality are elucidated. The methodology for the evaluation of the sensory characteristics of VOOs is reported, and typical flavours and off-flavours are described. Relationships between chemical compounds and sensory characteristics are evaluated using the new sensory analyses method promoted by the International Olive Oil Council (IOOC) and included recently in EU regulation (Reg. 1348/2013 and following revisions). Oil quality may be defined in a number of ways, but the sensory perception of flavour is the ultimate determinant.
The effect of using water and talc to improve oil yield was examined for the case of the Carrasqueña cultivar for the first time. The influence of these treatments to the antioxidant content (phenols and tocopherols) and quality parameters of the oil are discussed with regard to findings for Picual cultivar (a cultivar extensively studied in the past for various reasons) oils extracted and analyzed under the same conditions. Before the oil extraction the fruits from both cultivars were characterized for the ripening index, flesh/stone ratio, moisture, oil content, and instrumental color of fruits and crushed fruits. Water addition caused a decrease in oil yield and extractability, an increase in the peroxide index and a decrease in K270 and the total phenol content, whereas the instrumental color was scarcely affected. Talc addition resulted in an increase in oil yield and extractability, a decrease in the peroxide index and α-tocopherol content and a marked effect on the instrumental color measurement. Results show that for both Carrasqueña and Picual cultivars (fruits with a ripening index of 5.14 and 4.92, and a moisture content of 53.0 and 56.2%, respectively) water addition at a 42.9% w/w is not advisable. Conversely, talc addition increases oil yield without affecting negatively the quality parameters, although it decreases α-tocopherol content and has a marked effect on oil color.
The potential of stepwise orthogonalisation of predictors (SELECT) coupled with multivariate calibration methods and pre-processing tools was examined to develop reliable and parsimonious regression models based on Fourier-transform mid-infrared (FT-MIR) spectroscopy for the prediction of peroxide value in extra virgin olive oils. The comprehensive calibration methodology proposed also involved the study of the structure of noise present in data, the preliminary detection of anomalous objects, and the appropriate construction of calibration sets. The improvement achieved through the application of feature selection was particularly remarkable when SELECT-Ordinary Least Squares (OLS) was applied on first-derivative spectra. In this case, a high-quality OLS model was obtained, providing a predictive ability similar to that achieved by full spectrum approaches (after noise removal and signal pre-processing) and with no significant signs of over-fitting (4.9, 5.3 and 5.2% root-mean-square errors of the residuals obtained in calibration, cross-validation and external prediction, respectively), but considerably improved properties in terms of model parsimony and interpretability. In fact, it should be noted that only 12 relevant predictors from a total of 408 original wavenumbers were selected to model peroxide value, which meant a very notable compression rate. The quality of the results obtained encourages the feasibility of implementing a FT-MIR based calibration strategy similar to that proposed in routine analysis for the assessment of other critical quality parameters for olive oil.
The main objective of this study was to advance our knowledge of the relationship between minor component profiles and the quality and sensory perception of PDO (Protected Designation of Origin) Virgin Olive Oils (VOO) such as the Cornicabra PDO Montes de Toledo (Toledo, Spain), which is characterized by medium–high levels of phenolic compounds and medium–intense bitterness and pungency.Sensory analysis was performed in 60 Cornicabra virgin olive oils, which were categorized into virgins and extra virgins, by the official test panel of the Consejo Regulador de la Denominación de Origen Montes de Toledo (CRDO, Toledo), as recognized by the International Olive Council (IOC). The experimental results show that a significant increase in the oxidation index “peroxide value” and the presence of the sensory defect “wet wood” in the VOO, which were due to the freezing of the olives while on the tree, did not significantly affect the levels of phenolic compounds and tocopherols in the oils. This is of major importance due to the antioxidant and nutraceutical properties attributed to these compounds. The relationship between the phenolic components and the characteristic bitterness in Cornicabra virgin oils, which can be enhanced by volatile compounds related to the green notes, was confirmed. A good correlation was also found between the “wet wood” attribute, which has recently been recognized as a sensory defect by the International Olive Council, and the volatile compounds 2-methylbutanal and 3-methylbutanal.
In this paper, oleuropein and some other related phenolic compounds are reviewed. Their occurrence, distribution, biosynthesis and transformation during maturation and during industrial processing (preparation of table olives and oil production) are described. Their role in human health is proposed based on current human, animal and in vitro studies as molecules with antioxidant and antimicrobial properties.© 2000 Society of Chemical Industry
The bitterness of the main compounds identified in the phenolic extract of virgin olive (Olea europaea L.) oils has been sensory-tested. The aldehydic form of oleuropein aglycone (AOA) was responsible for this attribute. Correlations
between the sensory bitterness and concentrations of secoiridoid derivatives, analyzed separately or in different combinations,
were obtained for olive oils from different olive varieties. The best correlation obtained corresponds to AOA content (r=0.96; P=1.83×10−17) in the concentration range of 0.03 to 0.5 mmol/kg. AOA concentrations ≥0.5 mmol/kg produce sensory saturation of this attribute.
The correlation with AOA concentration was better than that with the absorbance of the phenolic extract at 225 nm. Therefore,
the equation obtained allows the evaluation of the bitterness in virgin olive oils by HPLC analysis of the phenolic extract
using detection at 280 nm.
Green, unripe olives were subjected to post-harvest treatment under a CO2 atmosphere for a period of 12 days. The total polyphenol (TP), total flavonoid (TFd) and total anthocyanin (TA) contents, along with the antioxidant and sensory characteristics, were continuously monitored during the treatment on a 24 h-interval basis, in order to identify possible changes in the quality of olives related mainly to changes in the polyphenolic contents. The storage of olives under CO2 atmosphere resulted in pronounced increases in TP and TF contents, mainly within the first 3-5 days, but TA exhibited a different pattern of evolution. Furthermore, storage under CO2 contributed to flavour appearance with the development of fruity/floral notes, and reduced bitterness. The in vitro antioxidant properties of the CO2-treated sample showed notable increases compared with the sample stored under regular atmospheric conditions. It was concluded that storage of olives under a CO2 atmosphere resulted in the appearance of desired sensory attributes, by decreasing bitterness and developing aroma and colour, and the functional (antioxidant) properties were improved. This approach may be used as an alternative, chemical-free means of table olive debittering.
Olives (Olea europaea cv. Chondrolia) were stored under a CO2 atmosphere immediately after harvesting for a period of 12 days. Samples obtained at 24-h intervals were analyzed by HPLC to identify components that may reflect changes in the biochemical behavior of the tissue. Four substances were shown to undergo significant fluctuations during storage, while their evolution was found to be different in olives stored under CO2 from those stored under regular atmospheric conditions (control). On the basis of data provided by liquid chromatography-electrospray ionization mass spectrometry, these substances were tentatively identified as hydroxytyrosol glucoside, demethylated ligstroside aglycone, ibotalactone A methyl ester, and verbascoside. The data are discussed in relation to the effect of postharvest treatments of olives for purposes of manipulating their polyphenolic content and plausible development of novel debittering processes.
Volatile compounds, retained by virgin olive oils during their extraction process, are responsible for the oil aroma. Approximately one hundred and eighty compounds, whose structure was assigned by means of gas chromatography-mass spectrometry, were found in virgin olive oil aromas. The analytical approaches to their determination are briefly discussed, considering the problems related to the volatile compound collection and to adsorbents used for their trapping.The sensory methodology for the evaluation of the organoleptic characteristics of the virgin olive oils are reported and typical flavours and off-flavours are described. Compounds responsible for flavours, including factors affecting the volatile fraction, and for off-flavours are carefully examined, also considering the causes that give rise to off-flavours. Relationships between volatile compounds and sensory characteristics, found by various researchers, are reviewed.
Hydroperoxide lyase catalyses the cleavage of hydroperoxides from polyunsaturated fatty acids to yield oxoacids and volatile aldehydes. Some of these aldehydes are constituents of the aroma of many fruits and vegetables, and are the major components of the aroma of virgin olive oil. The enzyme has been extracted by solubilization of membrane fractions prepared from the pulp tissues of developing olive fruits. Partial purification by ion-exchange and hydroxyapatite chromatography resulted in the resolution of two isoforms of the enzyme of similar properties: both showed optimal pH at 6.0 and were active with 13-fatty acid hydroperoxides only. The activity measured with 13-EZZ-hydroperoxy-linolenate was 2.5-fold higher than that measured with 13-EZ-hydroperoxylinoleate. Both enzymes showed high affinity for 13-hydroperoxides, with Km values in the micromolar range. The involvement of this enzyme activity in the formation of volatile aldehydes, present in the aroma of olive oil, is discussed.
Hydroperoxide lyase catalyses the cleavage of hydroperoxides from polyunsaturated fatty acids to yield oxoacids and volatile aldehydes. Some of these aldehydes are constituents of the aroma of many fruits and vegetables, and are the major components of the aroma of virgin olive oil. The enzyme has been extracted by solubilization of membrane fractions prepared from the pulp tissues of developing olive fruits. Partial purification by ion-exchange and hydroxyapatite chromatography resulted in the resolution of two isoforms of the enzyme of similar properties: both showed optimal pH at 6.0 and were active with 13-fatty acid hydroperoxides only. The activity measured with 13-EZZ-hydroperoxy-linolenate was 2.5-fold higher than that measured with 13-EZ-hydroperoxylinoleate. Both enzymes showed high affinity for 13-hydroperoxides, with Km values in the micromolar range. The involvement of this enzyme activity in the formation of volatile aldehydes, present in the aroma of olive oil, is discussed.
Olives (Olea europaea cv. Blanqueta and Villalonga) used for oil production (130 000 kg for each variety) were stored at two different temperatures (ambient and 5 °C) on an industrial scale. Refrigeration of the olives at 5 °C delayed deterioration of the physical, chemical, and sensorial parameters, measures of oil quality, allowing an additional 30 days of storage without changes in the initial oil quality. The Blanqueta variety does not maintain oil quality under cold storage as well as the Villalonga variety. Keywords: Olea europaea; postharvest; refrigeration; oil quality
Olives (Olea europaea cv. Picual) used for oil production were stored for 60 days at three different temperatures (ambient, 5 °C, and 8 °C) in containers used for fruit storage, each with a capacity for 64 kg of olives. The quality of both the fruits and the oils extracted from these fruits was analyzed. Fruit storage at 5 °C maintained the initial sensorial and chemical qualities of the oil for 45 days, but at 8 °C, these qualities were maintained for only 15 days. At room temperature, these qualities deteriorated just after 7 days of storage. Keywords: Olea europaea; postharvest; refrigeration; cold storage
Olive (Olea europaea cv. Picual) fruits were stored under different conditions of controlled atmosphere (CA) and temperature. Decay incidence for olives kept at ambient temperatures (6-17-degrees-C; 65-70% relative humidity) reached nearly 100% after 15-30 days, with a rapid decrease in all of the quality indexes assayed. The severe loss of water, because of the low relative humidity, caused shriveling. Storage in air at 5-degrees-C gave the lowest incidence of physiological disorders and decay. Storage at 5-degrees-C and 3% CO2 + 5% O2 for up to 30 days delayed ripening as indicated by retention of green color and flesh firmness. However, this storage system for longer than 30 days resulted in higher incidence of chilling injury and rot.
Sixty-five volatile compounds and 103 sensory attributes were evaluated in 32 virgin olive oil samples from three different
Mediterranean countries. Volatile compounds were analyzed with a dynamic headspace gas-chromatographic technique by using
a thermal desorption cold-trap injector. The sensory analysis was conducted by six panels composed of assessors from the United
Kingdom, Spain, the Netherlands, Greece and Italy. Principal-components analysis of sensory attributes was used to construct
a statistical sensory wheel that represents the whole virgin olive oil flavor matrix. This wheel is composed of seven sectors
that show the basic perceptions produced by the oil: green, bitter-pungent, undesirable, ripe olives, ripe fruit, fruity and
sweet. The boundaries of each sector were calculated from the circular standard deviation of its sensory attributes. The relationship
between sensory and instrumental analysis was determined by projecting volatiles onto the sensory wheel. Correlations of each
volatile with the first two components of the principal-components analysis were taken as its coordinates (x, y) in the sensory wheel. Volatiles took up the most appropriate place within the sector that corresponded with their perception,
and often close to the sensory attributes that explained their sensory properties. A gas-chromatographic/sniffing method was
applied to virgin olive oil samples to assess the aroma notes that corresponded to olive oil volatile compounds and to verify
the relationships found by the sensory wheel procedure. Most (89%) of the volatiles were well classified. Use of the statistical
sensory wheel as an appropriate method to relate volatile and sensory data was clearly demonstrated.
An analytical method has been developed to evaluate the intensity of the bitter taste in virgin olive oil. Results from the
proposed method, based on extraction of the bitter constituents of virgin olive oil with methanol/water and measurement of
the absorbance at 225 nm, show a significant correlation with the intensity of bitterness that had been evaluated in a sensorial
manner by a panel. The developed method, therefore, offers a real alternative to the panel test for the evaluation of this
attribute.
This paper describes a study of the influence of the extraction system, crop season and production area on the chemical composition and quality of Cornicabra virgin olive oils (n=152) from five successive crop seasons (from 1994/1995 to 1998/1999). Analysis of the effect of the extraction system (dual-phase, triple-phase decanters and pressure) on the values of analytical determinations, revealed statistically significant differences (P⩽0.05) in a few parameters only, mainly in antioxidant content (total phenols and α-tocopherol) and oxidative stability. All quality indices and major fatty acid and sterol compositions presented significant statistical differences (P⩽0.001) with respect to the year of production, with the exception of total phenols. The crop season is therefore a critical variable, since the chemical composition of the olive oil may vary considerably from one year to the next. Many of the analytical parameters varied among the five production areas considered, in the provinces of Toledo and Ciudad Real. The results appear to confirm the general consensus on the quality of Cornicabra virgin olive oils from Castilla-La Mancha, namely that oils from mills located in the south and southeast of the province of Toledo are generally of higher quality.
Storage of olives in sea water is a traditional way of fruit storage in olive oil production in Croatia that is still in frequent use. The changes of volatile compounds of olive oil, responsible for positive and negative odor properties that occur during this kind of fruit storage, were investigated. The influence of sea water was compared to brine and drinking water and with storage in the open air. The composition and content of volatile compounds were determined by dynamic headspace analysis with direct connection to gas chromatography and mass spectrometry. No significant differences were found among aqueous media. The olive oils from aqueous media had an essentially different composition and content of positive as well of negative volatile compounds in comparison to the reference sample and the samples stored in the air. The analytical method can give useful information about fruit storage before olive oil extraction.
The effect of the use of cell-wall-degrading-enzyme preparations during the mechanical extraction process of virgin olive oil on the phenolic compounds and polysaccharides was investigated. The use of the enzyme preparations increased the concentration of phenolic compounds in the paste, oil, and byproducts Especially, the contents of secoiridiod derivatives such as the dialdehydic form of elenolic acid linked to 3,4-dihydroxyphenylethanol (3,4-DHPEA-EDA) and an isomer of oleuropein aglycon (3,4-DHPEA-EA), which have high antioxidant activities, increased significantly in the olive oil. Furthermore,the use of an N-2 flush during processing strongly increased the phenolic concentration. Analyses of the pectic polymers present in the paste showed that the use of pectinolytic enzyme preparations increased the yield of the buffer soluble pectins and the proportion of molecules with a lower molecular mass; Also, the content of uronic acids in the buffer soluble extract increased considerably due to the use of the enzyme preparations. Analysis of the polymeric carbohydrates in the vegetation waters showed the presence of mainly pectic polymers. The addition of commercial enzyme preparations increased the uronic acid content of the polysaccharides in the vegetation, water substantially compared to the blank. This study showed that the addition of cell-small-degrading enzymes did improve the olive oil quality; however, mechanisms remained unclear.
Malaxation of olive paste must be considered to be much more than a simple physical separation, because a complex bioprocess takes place that is very relevant to the quality and composition of the final product. A combined study of the effect of kneading temperature and time on the minor composition of olive paste and its corresponding virgin olive oil, processed in an experimental oil mill (Pieralisi, Fattoria) with a working capacity of 200 kg/h, is reported. A large drop in the oleuropein content in the olive paste with respect to its initial content in the olive fruit (between 92 and 96%) was observed, which suggested its almost total degradation during the crushing operation. The major phenolic compound found in the olive paste during kneading was the dialdehydic form of elenolic acid linked to hydroxytyrosol (3,4-DHPEA-EDA, always higher than 60% of the total phenols). This greatly decreased during malaxation (from 5505 to 2317 mg/kg, on average). The content of phenolic compounds in virgin olive oil was much more affected by the malaxation temperature than the kneading time. For instance, the 3,4-DHPEA-EDA content increased by 220-630% in the two batches when the temperature was increased from 20 to 40 degrees C. A reduction in the C6 aldehydes was found in virgin olive oil as the malaxation temperature increased, especially in E-2-hexenal (30% reduction). In contrast, C6 aldehydes in the oils from the oil mill plant significantly increased as the malaxation time increased from 30 to 90 min, chiefly E-2-hexenal (about a 70% increase).
Green mature olives (Olea europaea L. cv. 'Manzanilla', 'Picual', and 'Verdial') were stored at 5 degrees C, and the oil extracted from them showed a middle intensity level of sensory-evaluated bitterness. The storage times necessary for this reduction were different for the three varieties tested, requiring 4, 6, and 8 weeks, respectively, for 'Manzanilla', 'Picual', and 'Verdial' olives. The level of commercial quality of the extracted oil did not deteriorate as a consequence of previous fruit storage. Olives matured during refrigeration at 5 degrees C, as the increase of maturation index and the decrease of color index and fruit firmness indicated. Similarly, as the fruit storage period progressed, the total phenolic compound content of the extracted oils decreased. Although the use of green mature olives may require a more prolonged storage time, it allows for a better postharvest handling of the fruits, which are more resistant to physical damage or fungal infections than the riper ones.
Publisher Summary This chapter discusses about olive oil, which is the oil extracted from the fruit of the olive tree. Most of the world supply of olive oil originates from the Mediterranean countries. Olive oil of good quality is characterized by a fragrant and delicate flavor, which is appreciated by the international gourmet and cherished by the native consumer. Large quantities of olive oil must be refined, mainly because it came from poor quality fruit. The olive tree is a relatively small evergreen tree, with narrow silvery leaves and small white flowers, known for its longevity. The botanical progenitor of the olive is thought to be the oleaster, olea sylvestris, a wild type of olive with a small, skinny fruit, still growing around the Mediterranean Sea and occasionally used as grafting stock. Handpicking from the tree undoubtedly yields fruit of the best quality for both the table olive and the olive oil industries. The time of optimum maturity may vary among years, cultivation areas, trees within the same grove, or individual fruits on the same tree. The oil extracted from the sound olive fruit by mechanical means is known as virgin olive oil and is marketed without additional processing. Squalene, a biochemical precursor of sterols, is the main hydrocarbon of olive oil. The polycyclic aromatic hydrocarbons identified in olive oil include phenanthrene, pyrene, fluoranthrene, 1, 2-benzanthracene, chrysene, and perilene. Olive oil, like all edible oils, undergoes deterioration during storage. Storing olive oil in tanks is a common practice.
A simple analytical method for the quantitative determination of phenols, flavones, and lignans in virgin olive oils was developed. The polar fraction was isolated from small amounts of oil sample (2.5 g) by solid-phase extraction (SPE) using diol-phase cartridges, and the extract was analyzed by reversed-phase HPLC coupled with diode array UV detection. Chromatographic separation of pinoresinol, cinnamic acid, and 1-acetoxypinoresinol was achieved. Repeatability (RSD < 6.5%), recovery (> 90%), and response factors for each identified component were determined. SPE on amino-phase cartridges was used for isolating acidic phenols and as an aid for phenol identification. For the first time, 2-(4-hydroxyphenyl)ethyl acetate was detected in olive oils. The aldehydic structure of the ligstroside aglycon was confirmed by NMR spectroscopy. The colorimetric determination of total o-diphenolic compounds by reaction with molybdate was consistent with their HPLC determination. Differences between results obtained by liquid-liquid extraction and SPE were not statistically significant.
Olives (Olea europaea cv. Cobrançosa, Madural, and Verdeal Transmontana) used for oil production were stored, in plastic containers, at 5 +/- 2 degrees C (70% relative humidity) for three different periods before oil extraction: 0, 7, and 14 days (T(0), T(7), and T(14), respectively). In the crop year 1997/1998 this procedure was done only for cv. Cobrançosa and in 1998/1999 for the three cultivars. After storage, the oils were extracted from the fruits, and the acidity, peroxide value, coefficients of specific extinction at 232 and 270 nm, stability, color, p-anisidine value, fatty acids, and tocopherols compositions were determined. The results confirm that storage of fruits produces losses in the olive oil quality. Acidity and stability to oxidation indicate a progressive deterioration of oil quality as fruit is stored. The storage time affects the total tocopherols contents, namely, alpha-tocopherol, which clearly decreased during fruit storage. The oil quality of the Verdeal Transmontana cultivar deteriorated more rapidly than that of Cobrançosa and Madural cultivars. This study also shows that cv. Cobrançosa, the main cultivar in the region, is a good choice in terms of final olive oil quality.
The efficiency of headspace solid-phase microextraction (SPME) was evaluated for the qualitative and semi-quantitative analysis of virgin olive oil volatile compounds. The behaviour of four fibre coatings was compared for sensitivity, repeatability and linearity of response. A divinylbenzene-Carboxen-polydimethylsiloxane fibre coating was found to be the most suitable for the analysis of virgin olive oil volatiles. Sampling and chromatographic conditions were examined and the SPME method, coupled to GC with MS and flame ionization detection, was applied to virgin olive oil samples. More than 100 compounds were isolated and characterised. The presence of some of these compounds in virgin olive oil has not previously been reported. The main volatile compounds present in the oil samples were determined quantitatively.
Polyphenols are an important functional minor component of virgin olive oils that are responsible for the key sensory characteristics of bitterness, pungency, and astringency. Polyphenols were isolated from virgin olive oils by using liquid/liquid extraction and then separated by using reverse phase HPLC followed by fraction collection. The sensory qualities of the isolated polyphenols were evaluated, and almost all fractions containing polyphenols were described as bitter and astringent. However, the fraction containing deacetoxy-ligstroside aglycon produced a strong burning pungent sensation at the back of the throat. In contrast, the fraction containing the analogous deacetoxy-oleuropein aglycon, at an equivalent concentration, produced only a slight burning/numbing sensation, which was perceived more on the tongue. No other polyphenol fractions from the analyzed oils produced the intense burning sensation; thus, deacetoxy-ligstroside aglycon is the polyphenol responsible for the majority of the burning pungent sensation found in pungent extra virgin olive oils.
Twenty virgin olive oils of extra quality and different bitter intensity were submitted to sensory evaluation and to the determination of polyphenols. A linear regression analysis was carried out assuming, as an independent variable, bitter intensity perceived by tasters, as an independent variable, the concentration (mmol/kg) of dialdehydic and aldehydic forms oleuropein aglycon, and dialdehydic and aldehydic forms ligstroside aglycon. Structural confirmation of these compounds was done by online high-performance liquid chromatography-electrospray ionization-collison-induced dissociation-mass spectrometry. The results obtained demonstrate the essential role played by this compound in the bitter taste of virgin olive oil.
This study presents the phenolic compounds profile of commercial Cornicabra virgin olive oils from five successive crop seasons (1995/1996 to 1999/2000; n = 97), determined by solid phase extraction reversed phase high-performance liquid chromatography (SPE RP-HPLC), and its relationship with oxidative stability, processing conditions, and a preliminary study on variety classification. The median of total phenols content was 38 ppm (as syringic acid), although a wide range was observed, from 11 to 76 ppm. The main phenols found were the dialdehydic form of elenolic acid linked to tyrosol (p-HPEA-EDA; 9 +/- 7 ppm, as median and interquartile range), oleuropein aglycon (8 +/- 6 ppm), and the dialdehydic form of elenolic acid linked to hydroxytyrosol (3,4-DHPEA-EDA; 5 +/- 8 ppm). In many cases the correlation with oxidative stability was higher when the sum of the dialdehydic form of elenolic acid linked to hydroxytyrosol (3,4-DHPEA-EDA) and oleuropein aglycon (r (2) = 0.91-0.96) or the sum of these two and hydroxytyrosol (r (2) = 0.90-0.97) was considered than was observed with HPLC total phenols (r (2)= 0.91-0.95) and especially with colorimetric determination of total polyphenols and o-diphenols (r (2) = 0.77-0.95 and 0.78-0.92, respectively). 3,4-DHPEA-EDA, p-HPEA-EDA, the aglycons of oleuropein and ligstroside, and HPLC total phenols content presented highly significant differences (p = 0.001-0.010) with respect to the dual- and triple-phase extraction systems used, whereas colorimetric total polyphenols content did not (p = 0.348) and o-diphenols showed a much lower significant difference (p = 0.031). The five variables that most satisfactorily classified the principal commercial Spanish virgin olive oil varieties were 1-acetoxypinoresinol, 4-(acetoxyethyl)-1,2-dihydroxybenzene (3,4-DHPEA-AC), ligstroside aglycon, p-HPEA-EDA, and RT 43.3 contents.
Increasing interest in phenolic compounds in olives is due to their antioxidant and health-enhancing properties. In this study the phenolics in fruits of the Tunisian olive cultivar Chemlali were extracted by methanol-water and fractionated using Sephadex LH-20 column chromatography. The identification of phenolic monomers and flavonoids was based on separation by high-performance liquid chromatography equipped with a diode array detector followed by liquid chromatography-mass spectrometry and gas chromatography-mass spectrometry analysis. Oleuropein, a secoiridoid glycoside esterified with a phenolic acid, was the major compound. Eight phenolic monomers and 12 flavonoids were also identified in Chemlali olives. Five flavonoids were isolated and purified using Sephadex LH-20 column chromatography and preparative paper chromatography. The antioxidant activity of the extract and the purified compounds was evaluated by measuring the radical scavenging effect on 1,1-diphenyl-2-picrylhydrazyl and by using the beta-carotene-linoleate model assay. Acid hydrolysis of the extract enhanced its antioxidant activity. Hydroxytyrosol and quercetin showed antioxidant activities similar to that of 2,6-di-tert-butyl-4-methylphenol. A hydroxyl group at the ortho position at 3' on the B ring of the flavonoid nucleus could contribute to the antioxidant activity of the flavonoids.
Anthocyanins (Anths) in olive (Olea europaea L.) fruits at different degrees of pigmentation were assessed nondestructively by measuring chlorophyll fluorescence (ChlF). The method is based on the comparison of the ChlF excitation spectra from olives with different pigmentation from green to green-red, reddish-purple, and purple. The logarithm of the ratio between the fluorescence excitation spectra (logFER) from two different colored zones gave the difference in the absorption spectrum between them. The absorbance spectrum derived from the logFER between a red olive and the same olive devoid of the skin showed the typical Anth green band (at 550 nm). It matched that recorded by microspectrophotometry on a single pulp cell and the in vitro absorbance spectrum of the olive skin extract. As expected, the in vivo Anths absorption maximum increased in intensity going from less to more mature olives and was higher in the sun-exposed olive side with respect to the sun-shaded side. Absolute quantitative nondestructive determination of Anths for each olive sample was obtained by the logFER calculated for two excitation wavelengths, 550 and 625 nm, of ChlF at 740 nm. Going from green to purple skin colors, the Log[ChlF(625)/ChlF(550)] was fairly well-correlated to the extract Anths concentration. Finally, the relationship between the Anths and the other main phenolics present in the olives analyzed by high-performance liquid chromatography was evaluated. The main result was a net increase of verbascoside with increasing Anths content. On the basis of our results, the development of a new rapid and noninvasive method for the monitoring of olive development and ripening can be envisaged.
The study of the antioxidant effects of biophenolic compounds is supported by the current interest in natural products and the ongoing replacement of synthetic antioxidants by natural antioxidants from plant sources. Olives and olive oil, especially extra virgin olive oil, contain a variety of bioactive compounds (phytochemicals) widely considered to be potentially beneficial for health. This research was focused on evaluating the antioxidant activity of the enriched refined olive oil to discover a possible functional food application. Different concentrations of individual and combined phenolic compounds were added to the refined olive oil as lipid matrix, and the antioxidant activity expressed as oxidative stability in hours was determined by using the Rancimat method. Additionally, the bitter index was evaluated to assess the effect of the enrichment in relation to the organoleptic quality. The results showed that the antioxidant activity depends on the concentration of the phenol used for the assay and the chemical structure. In general, the most positive effects were observed in 3,4-dihydroxy and 3,4,5-trihydroxy structures linked to an aromatic ring that conferred to the moiety a higher proton dislocation, thus facilitating the scavenging activity.
'Frantoio' olive fruits were stored at low temperature (4 +/- 2 degrees C) for 3 weeks to investigate the effect of postharvest fruit storage on virgin olive oil quality. Volatile compounds and phenolic compounds explained the changes in sensory quality that could not be explained with quality indices (FFA, PV, K232, and K270). Increases in concentrations of ( E)-2-hexenal and hexanal corresponded to positive sensory quality, whereas increases in ( E)-2-hexenol and (+)-acetoxypinoresinol were associated with negative sensory quality. Volatile and phenolic compounds were also indicative of the period of low-temperature fruit storage. Oleuropein and ligstroside derivatives in olive oil decreased with respect to storage time, and their significant ( p < 0.05) change corresponded to changes in bitterness and pungency. ( Z)-2-Penten-1-ol increased during low-temperature fruit storage, whereas 2-pentylfuran decreased. Changes in volatile compounds, phenolic compounds, quality indices, and sensory notes indicated that virgin olive oil quality was lost within the first week of low-temperature fruit storage and regained at 2 weeks. This research suggests that low-temperature olive fruit storage may be beneficial, with a possibility of increasing oil yield and moderating the sensory quality of virgin olive oils. This study demonstrates that deeper insights into virgin olive oil quality changes during low-temperature fruit storage may be gained by studying volatile and phenolic compounds in addition to quality indices and physical appearance of the fruit.
In Postharvest Physiology and Storage of Tropical and Subtropical Fruits
- J M Olias
- J M Garcıá
- Olive
Olias, J. M.; Garcıá, J. M. Olive. In Postharvest Physiology and
Storage of Tropical and Subtropical Fruits; Mitra, S., Eds.; CAB
International: Wallingford, UK, 1997; pp 229-243.
Storage of olives (Olea europaea L.) under CO 2 atm: Liquid chromatography-(27) Phenolic compounds profile of Cornicabra virgin olive oil
- V G Dourtoglou
- A Mamalos
- D P Makris
- A Kefalas
- S Goez-Alonso
- M D Salvador
- G Fregapane
Dourtoglou, V. G.; Mamalos, A.; Makris, D. P.; Kefalas, A. Storage of olives (Olea europaea L.) under CO 2 atm: Liquid chromatography-(27) Goez-Alonso, S.; Salvador, M. D.; Fregapane, G. Phenolic compounds profile of Cornicabra virgin olive oil. J. Agric. Food Chem. 2002, 50, 6812–6817.
Influence of volatile compounds on virgin olive oil quality evaluated by analytical approaches and sensor panels Received for review July 18 Revised manuscript received March 15 This research was supported by the Junta de Comunidades de Castilla-La Mancha
- F Angerosa
Angerosa, F. Influence of volatile compounds on virgin olive oil quality evaluated by analytical approaches and sensor panels. J. Agric. Food Chem. 2002, 104, 639–660. Received for review July 18, 2009. Revised manuscript received March 15, 2010. Accepted March 17, 2010. This research was supported by the Junta de Comunidades de Castilla-La Mancha
Informe sobre la utilizacio´ analizador de rendimientos " Abencor " . Grasas aceites
- A Lanzo´
Lanzo´, A. Informe sobre la utilizacio´ analizador de rendimientos " Abencor ". Grasas aceites 1975, 26, 379–385.
Olive oil: a review Eds.; American Oil Chemists' Society Quality of picual olive fruits stored under controlled atmospheres
- A Kiritsakis
- P Markakis
- J M Castellano
- J M Garcia
- A Morilla
- S Perdiguero
- F Gutierrez
CITED
(1) Kiritsakis, A.; Markakis, P. Olive oil: a review. In Olive Oil;
Kiritsakis, A. K., Eds.; American Oil Chemists' Society: Champaign,
IL, 1991.
(2) Castellano, J. M.; Garcia, J. M.; Morilla, A.; Perdiguero, S.;
Gutierrez, F. Quality of picual olive fruits stored under controlled
atmospheres. J. Agric. Food Chem. 1993, 69, 1215-1218.
European Commission Regulation (EEC) Number 702/2007 amending Commission Regulation (EEC) Number 2568/91 on the characteristics of olive oil and olive-residue oil and on the relevant methods of analysis
AENOR. Spanish standard, UNE55032-73; Asociacio´nAsociacio´n Espa~ nola de
Normalizacio´nNormalizacio´n y Certificacio´nCertificacio´n: Madrid, 1973.
(16) European Commission Regulation (EEC) Number 702/2007 amending Commission Regulation (EEC) Number 2568/91 on the characteristics of olive oil and olive-residue oil and on the relevant
methods of analysis. Off. J. Eur. Union 2007, L161 (June 22),
11-27.