Chemical composition and oxidative stability of Tunisian monovarietal virgin olive oils with regard to fruit ripening

NMR Analysis of Extra Virgin Olive Oil of the Epirus Region of Greece with Emphasis on Selected Phenolic Compounds

Extra virgin olive oil (EVOO) is recognized for its numerous health benefits, attributed to its rich phenolic components. NMR has emerged as a prevalent technique for precisely identifying these compounds. Among Mediterranean countries, Greece stands as the third-largest producer of olives, with the Epirus region notably advancing in olive cultivation, contributing significantly to the dynamic growth of the region. In this study, an NMR method was employed based on the acquisition of a 1H NMR spectrum along with multiple resonant suppression in order to increase the sensitivity. Using the above method, 198 samples of extra virgin olive oil, primarily sourced from the Epirus region, were analyzed, and both the qualitative and quantitative aspects of the phenolic compounds were obtained. In addition, we examined the effects of various factors such as variety, harvest month, and region origin on the phenolic compounds' concentration. The results revealed an average total phenolic content of 246 mg/kg, closely approaching the EU health claim limit of 250 mg/kg. Approximately 15% of the samples were confidently characterized as high-phenolic olive oil. The highest concentrations were observed in the Thesprotia samples, with several Lianolia varieties exceeding the total phenolic content of 400 mg/kg. Statistical tests demonstrated a significant influence of the olive variety and the month of fruit harvest on phenolic component concentration, followed by the region of origin. A very strong correlation was noted between the total phenolics content and the levels of oleocanthal and oleacein, with a correlation coefficient (r) of 0.924. Upon optimization of all factors affecting olive oil quality, the majority of the EVOOs from the Epirus region have the potential to be characterized as high in phenolic content.

Functional Characterization of Four Olive Squalene Synthases with Respect to the Squalene Content of the Virgin Olive Oil

The release of new olive cultivars with an increased squalene content in their virgin olive oil is considered an important target in olive breeding programs. In this work, the variability of the squalene content in a core collection of 36 olive cultivars was first studied, revealing two olive cultivars, 'Dokkar' and 'Klon-14', with extremely low and high squalene contents in their oils, respectively. Next, four cDNA sequences encoding squalene synthases (SQS) were cloned from olive. Sequence analysis and functional expression in bacteria confirmed that they encode squalene synthases. Transcriptional analysis in distinct olive tissues and cultivars indicated that expression levels of these four SQS genes are spatially and temporally regulated in a cultivar-dependent manner and pointed to OeSQS2 as the gene mainly involved in squalene biosynthesis in olive mesocarp and, therefore, in the olive oil. In addition, the biosynthesis of squalene appears to be transcriptionally regulated in water-stressed olive mesocarp.

Maturity impact on physicochemical composition and polyphenol properties of extra virgin olive oils obtained from Manzanilla, Arbequina, and Koroneiki varieties in Iran

This study investigated the physicochemical properties and polyphenol composition of extra virgin olive oils (EVOOs) extracted from three olive cultivars. The investigated cultivars were Arbequina, Koroneiki, and Manzanilla, grown in Olive Research Station in Rudbar county, Gilan province, Iran, at three ripening stages. Several parameters were analyzed, including peroxide and acidity values, unsaponifiable matter, oxidative stability, total aliphatic alcohols, fatty acids (FAs), sterols, and triacylglycerol composition. The results showed that as maturity increased, parameters such as oil content, acidity value, and iodine value, rise, while parameters including peroxide value, oxidative stability, aliphatic alcohols, and unsaponifiable matter decreased (p < .05). The saponification value was slightly reduced in the developing ripening process (p > .05). The MUFA/PUFA ratio and total sterol content declined during the olive ripening stages (p < .05). The triterpenes decreased in Arbequina and Koroneiki cultivars but increased in Manzanilla cultivar during the maturity stages. According to the data, oleuropein decreased while oleuropein aglycone, oxidized aldehyde, and hydroxylic form of oleuropein increased for all EVOOs during maturation. Apigenin, quercetin, ligstroside aglycone, aldehyde and hydroxylic form, ferulic acid, caffeic acid, and catechin decreased during the ripening of fruits (p < .05). The main triglycerides were triolein (OOO), palmitodiolein (POO), dioleolinolein (OOL), and palmitooleolinolein (PLO) in all EVOOs. In addition, the olive cultivar and harvesting date influence the physicochemical properties and polyphenol composition of EVOOs extracted from olive varieties grown in one region. In conclusion, the results can present helpful information to determine the optimum maturity stage for the investigated olive cultivars.

Identifying markers volatiles in Brazilian virgin oil by multiple headspace solid-phase microextraction, and chemometrics tools

A protocol was optimized to determine the volatile profile from monovarietal virgin olive oil (VOO) by multiple headspace solid-phase microextraction (MHS-SPME) followed by gas chromatography-mass spectrometry (GC-MS) analysis. For this, a Plackett-Burman (PB) and central composite rotational designs (CCRD) were used to define the best condition of extraction. Moreover, fatty acids profile and principal component analysis (PCA) was used to identify markers among the cultivars. The amount of 0.1 g of sample was enough to express the volatile composition of the olive oils by MHS-SPME. Volatile compounds [nonanal, (Z)-3-Hexen-1-ol, (Z)-3-Hexenyl Acetate, Hexyl Acetate, 3-Methylbutyl Acetate, (E)-2-Hexen-1-ol, (E)-2-Hexenyl Acetate] and fatty acids [C17:1, C18, C18:1, C18:2] were those reported such as the markers in the varieties of olive oils. The PCA analysis allowed the classification of the most representative volatiles and fatty acids for each cultivar. Through two principal components was possible to obtain 81.9% of explanation of the variance of the compounds. The compounds were quantified using a validated method. The MHS-SPME combined with multivariate analysis showed a promising tool to identify markers and for the discrimination of olive oil varieties.

Chemometric and Physico-Chemical Characterization of Fruit and Olive Oils from Autochthonous Cultivars Grown in Aragon (Spain)

Olive tree crops and the olive oil market are becoming less and less diverse due to the rise of intensive growth varieties, with the consequent loss of varietal richness provided by oils from minority and autochthonous cultivars. "Royal de Calatayud" and "Negral de Sabiñán" are two local minority cultivars in Aragon (Spain). Fruit parameters such as ripening, fresh weight, and oil yield were evaluated, as well as physico-chemical and chemical composition parameters in olive oil in comparison with "Arbequina", a cultivar widespread in Spain and other countries. Fruits were harvested from October to December in 2017 and 2019. Chemometric analysis revealed significant varietal differences among the three cultivars. In comparison with "Arbequina", higher oil yields were obtained in the two local cultivars. "Royal de Calatayud" has a higher oleic acid content and a greater quantity of phenolic compounds. It thus displays a better nutritional profile than "Arbequina". This preliminary study shows that "Royal de Calatayud" could be regarded as an excellent alternative to the "Arbequina" cultivar in the parameters analyzed.

Effect of Controlled Oxygen Supply during Crushing on Volatile and Phenol Compounds and Sensory Characteristics in Coratina and Ogliarola Virgin Olive Oils

In virgin olive oil industries, the technological choices of the production plant affect the biochemical activities that take place in the olives being processed throughout the entire process, thereby affecting the quality of the final product. The lipoxygenase pool enzymes that operated their activity during the first phases of the process need the best conditions to work, especially concerning temperature and oxygen availability. In this study, a system was equipped to supply oxygen in the crusher at a controllable concentration in an industrial olive oil mill at pilot plant scale, and four oxygen concentrations and two cultivars, Coratina and Ogliarola, were tested. The best concentration for oxygen supply was 0.2 L/min at the working capacity of 0.64 Ton/h. Further, using this addition of oxygen, it was possible to increase the compound's concentration, which is responsible for the green, fruity aroma. The effect on volatile compounds was also confirmed by the sensory analyses. However, at the same time, it was possible to maintain the concentration of phenols in a good quality olive oil while also preserving all the antioxidant properties of the product due to the presence of phenols. This study corroborates the importance of controlling oxygen supply in the first step of the process for process management and quality improvement in virgin olive oil production.

Crop year, harvest date and clone effects on fruit characteristics, chemical composition and olive oil stability from an Empeltre clonal selection grown in Aragon

BACKGROUND

In this study, the effects of crop year, harvest date and clone on the fruit characteristics and chemical composition of Empeltre olive oils were evaluated. For this purpose, the weight and oil content of fruit and the fatty acid composition, polyphenol content and oxidative stability of the olive oil was analysed throughout ripening during three successive seasons.

RESULTS

The weight and moisture in the fruit, as well as the fatty acids and polyphenol content in the olive oil, were mainly affected by crop year. In contrast, the stability was strongly influenced by the harvest date. Both factors had an influence on the fruit's oil content. The clone was not a substantial component in terms of variability, although the interaction with crop year was notable for some of the characteristics. The oil content increased significantly along with the harvest date and reached maximum values in the last period (44.9%). Conversely, stability and polyphenols decreased significantly (depending on the year, by 30-70%) from October to December, reaching the highest mean values between 1 October and 10 November (15.5 h; 500 mg caffeic acid kg^-1 ). Oleic acid and monounsaturated/polyunsaturated fatty acids (MUFA/PUFA) did not show significant differences depending on the harvest date, but between years, with 2018 having the highest percentage of oleic acid (72.72%) and MUFA/PUFA (8.38).

CONCLUSION

Early harvesting of Empeltre olives would provide considerably more stable olive oils, regardless of the clone selected, with higher phenolic content. It would not affect the MUFA/PUFA ratio, mainly influenced by the crop year. © 2022 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Geographical location and cultivar-linked changes on chemical properties of olive oils from Algeria

In the present work, we are assessing the geographical origin and cultivar-related changes on olive oil quality and composition in East Algeria. Fruits from the main local olive varieties (Sigoise and Chemlal) were harvested in autumn 2019 growing season from three different geographic areas: semiarid (Setif), arid (Batna), and Saharan (Eloued). Obtained results showed that Chemlal and Sigoise olive oils from Eloued area were the most enriched in tocopherols and phenolic contents, respectively. Sigoise olive oil from Batna area showed the highest values of pigments (carotenoids, chlorophylls). Identified fatty acids using gas chromatography (GC) coupled with mass spectrometry (MS) indicated that Chemlal cultivar olive oil from Batna was the most enriched in saturated fatty acid. However, higher levels of monounsaturated fatty acid were recorded for olive from Eloued and Setif areas. Sigoise cultivar oil displayed higher contents of unsaturated fatty acid in Batna, but higher levels of polyunsaturated fatty acid from Eloued location. These outcomes highlighted an actual impact of geographical location on each cultivar olive oil chemical proprieties. According to these data and relative to the International Olive Council (IOC) standards, all the analyzed olive oils could be categorized as extra virgin olive oils. Overall, statistical analysis showed that physicochemical parameters were influenced by the cultivar, the region of collection, as well as the interactions between them.

Influence of environmental growth temperature on tocopherol and sterol oil concentrations in olive fruit

BACKGROUND

Tocopherols and sterols are minor components of virgin olive oils that contribute to oil quality. Based on observations at different geographical locations, it has been suggested that environmental temperature during fruit growth affects tocopherol and sterol oil concentrations in olive fruit. However, controlled experiments have not been conducted to directly assess their responses to temperature. In this study, a manipulative experiment using open-top chambers (OTCs) was performed in the field to evaluate the responses of these oil components to a moderate air temperature increase during oil accumulation in young trees of two olive cultivars (Arbequina, Coratina). The two temperature levels in the OTCs were a control about 1 °C above ambient temperature (T0) and a heated treatment (T+) with a target temperature of 4 °C above T0.

RESULTS

Total tocopherol and sterol oil concentrations in olive fruit were generally higher in the T+ temperature treatment than in the control at the end of the oil accumulation period. The increase in total tocopherols in T+ appeared to be related to a decrease in fruit oil concentration with heating. Individual sterols showed both significant increases and decreases due to T+, and some differences in response occurred between the two cultivars.

CONCLUSION

These findings provide evidence that growth temperature affects tocopherol and sterol oil concentrations in olive fruit at the end of the oil accumulation period. Cultivars should be carefully chosen for new olive-growing regions, and the results could be relevant for global warming scenarios in existing growing regions. © 2021 Society of Chemical Industry.

Effect of Water Supplementation on Oxidant/Antioxidant Activities and Total Phenol Content in Growing Olives of the Morisca and Manzanilla Varieties

The objective of this work was to analyse, using a time series analysis, the effect of water regime for two cultivars at three stages of ripeness, during three consecutive years. Fruit and oil yield; O2− production and NADH oxidation activities; polyphenol oxidase (PPO), superoxide dismutase (SOD) and peroxidase (POX) activities; total phenols, flavonoid and phenylpropanoid glycoside content; and total antioxidant capacity (FRAP) were determined. All these parameters were found to depend on variety, irrigation and year. The results showed that the fruit and oil yields were strongly dependent on both irrigation and variety. The DW/FW ratio was practically constant during ripening, with small variety-dependent changes due to irrigation. Total amino acid and protein contents increased with ripening, with a close dependence on variety but not on irrigation. The SOD and POX activities appeared closely related, and related to the NADH oxidation and the amount of O2−. The evolution of phenols and FRAP during ripening was complementary to that of NADH oxidation, O2− production as well as SOD and POX activities. The determining factors of the SOD, POX and PPO activities were the variety and the ripening; the determining factor of the yield, ROS production, total phenols and antioxidant capacity was the water regime. Inverse correlations were observed between maximum temperature and total phenols (−0.869), total flavonoids (−0.823), total PPGs (−0.801) and FRAP (−0.829); and between DW/FW and irrigation (−0.483). The remaining significant correlations were positive.

Quantitatively Unraveling Hierarchy of Factors Impacting Virgin Olive Oil Phenolic Profile and Oxidative Stability

A single phenolic group and even a compound play different roles in the sensory properties and stability of virgin olive oil (VOO), which in turn are strongly influenced by several factors. Understanding the causes of differences in phenolic compound composition and oxidative stability (OS) in VOOs is essential for targeted and timely harvest and processing while maintaining desired oil quality. The phenolic profile and OS of two monocultivar VOOs (Oblica and Leccino) grown in two geographical sites of different altitudes (coastal plain and hilly hinterland) were analyzed throughout the ripening period over two years. Concentration of secoiridoids was 30% higher in the Oblica than in the Leccino VOOs, which in turn had significantly higher values of OS. Both cultivars had more than twice as high concentrations of the two most abundant phenolic compounds, the dialdehyde form of decarboxymethyl oleuropein aglycone and the dialdehyde form of decarboxymethyl ligstroside aglycone, and OS values in a colder growing site of higher altitude. Among the studied monocultivar VOOs, the secoiridoid group did not behave equally during ripening. The hierarchy of different influencing factors was investigated using multivariate statistics and revealed: cultivar > geographical site > harvest period > growing season. In addition, the possibility of traceability of VOO using molecular markers was investigated by establishing SSR profiles of oils of the studied cultivars and comparing them with SSR profiles of leaves.

Volatile-Olfactory Profiles of cv. Arbequina Olive Oils Extracted without/with Olive Leaves Addition and Their Discrimination Using an Electronic Nose

Oils from cv. Arbequina were industrially extracted together with olive leaves of cv. Arbequina or Santulhana (1%, w/w), and their olfactory and volatile profiles were compared to those extracted without leaves addition (control). The leaves incorporation resulted in green fruity oils with fresh herbs and cabbage olfactory notes, while control oils showed a ripe fruity sensation with banana, apple, and dry hay grass notes. In all oils, total volatile contents varied from 57.5 to 65.5 mg/kg (internal standard equivalents), being aldehydes followed by esters, hydrocarbons, and alcohols the most abundant classes. No differences in the number of volatiles were observed. The incorporation of cv. Arbequina or Santulhana leaves significantly reduced the total content of alcohols and esters (minus 37–56% and 10–13%, respectively). Contrary, cv. Arbequina leaves did not influence the total content of aldehydes or hydrocarbons, while cv. Santulhana leaves promoted a significant increase (plus 49 and 10%, respectively). Thus, a leaf-cultivar dependency was observed, tentatively attributed to enzymatic differences related to the lipoxygenase pathway. Olfactory or volatile profiles allowed the successful unsupervised differentiation of the three types of studied cv. Arbequina oils. Finally, a lab-made electronic nose was applied to allow the nondestructive discrimination of cv. Arbequina oils extracted with or without the incorporation of olive leaves (100% and 99 ± 5% of correct classifications for leave-one-out and repeated K-fold cross-validation variants), being a practical tool for ensuring the label correctness if future commercialization is envisaged. Moreover, this finding also strengthened that olive oils extracted with or without olive leaves incorporation possessed quite different olfactory patterns, which also depended on the cultivar of the olive leaves.

Changes in Quality and Antioxidant Properties of Virgin Olive Oil of 'Cornicabra' According to Fruit Maturation in Longnan, China

This work aims to study the influence of olive fruit maturity on physicochemical properties and antioxidant activity which determine the quality of virgin olive oils (VOO). According to the results, the values of all parameters were within the range specified by the Codex Alimentarius (2017). With the increase of fruit maturity, the oil content continued to increase until reached the maximum value (20.05%) in the 7th maturity (M7). K₂₃₂, K₂₇₀ and peroxide value (PV) decreased with the increase of maturity, while ΔK increased linearly with the increase of maturity. Free fatty acidity (FFA) first decreased and then increased, until reached the maximum value of (0.52 ± 0.03) % in M7. The total polyphenols (TP) and total flavonoids (TF) that characterized the antioxidant properties of olive oil increased with the increase of fruit maturity, which indicated that the oxidative stability (OS) of VOO of 'Cornicabra' increased with the increase of fruit maturity. The oleic acid (C18:1) content remained above 70 % and reached the maximum of (76.68 ± 0.17) % at M7. The values of monounsaturated fatty acids (MUFA) / polyunsaturated fatty acids (PUFA) and oleic acid (C18:1) / linoleic acid (C18:2) showed a decreasing trend with the maturity stage. Principal component analysis (PCA) showed that the quality of FFA, PV, K₂₃₂, K₂₇₀, TP, TF and OS were higher at the 5th maturity (M5), the quality of fatty acid were higher at M7. It can be seen from the analysis that the olive fruit maturity was an important parameter to characterize and distinguish olive oil.

Changes in secoiridoids content and chemical characteristics of cultivated and wild Algerian olive oil, in term of fruit maturation

Wild varieties in nature are known to be better adapted to climate change and more resistant to arid conditions common in some regions of the world. Oil samples of two cultivated varieties, Chemlal and Lemli, and one sylvestris variety were collected at four different harvesting periods in the semi-arid region of Bouira, Algeria. The aim of this study was to determine the influence of the genetic and maturity factors on the quality indices (acidity, peroxides value, and the parameters K232, K270), fatty acids profile, phenolic composition, and antioxidant activity of monovarietal olive oils. The study showed that early harvest dates of the fruits produced oils richer in pigments and phenolic compounds, with high antioxidant activity registered in both wild and cultivated varieties. Moreover, all oil samples showed high values of secoiridoids exceeding 60–90% of total biophenols, with higher values found in oleaster oils, which are correlated with high resistance to oxidation attacks. UHPLC-DAD and UHPLC-HRMS analyses showed that the secoiridoids composition is dominated by a profile rich in several isomers of oleuropein and ligstroside aglycons, which in turn represent more than 60% of the total secoiridoids in olive and Oleaster oils. Furthermore, chemometric analysis on the data allowed a better appreciation of the sensitivity of the virgin olive oil composition to the changes in genetic and ripening factors. According to the principal component analysis, phenolic and fatty acid profiles were the most important components contributing to the discrimination between olive oil samples.

On the Squalene Content of CV Chondrolia Chalkidikis and Chalkidiki (Greece) Virgin Olive Oil

This work is a continuation of efforts to establish the nutritional profile of virgin olive oil (VOO) from cv. Chondrolia Chalkidikis and Chalkidiki and to strengthen its positioning in the global VOO landscape. VOOs produced at an industrial scale in different olive mills of the Chalkidiki (Greece) regional unit as well as VOOs obtained at the laboratory scale from drupes of different maturity stages for four consecutive harvesting years were examined for their squalene (SQ) content using both HPLC and GC procedures. The mean values of SQ were found to be 4228 (HPLC) and 4865 (GC) mg/kg oil (n = 15) and were of the same magnitude as that in VOOs from cv Koroneiki (4134 mg/kg, n = 23). Storage of VOOs in the dark at room temperature for 18 months indicated an insignificant mean SQ content loss (~2%) in comparison to a mean loss of 26% for alpha-tocopherol content. This finding strengthens our view that SQ does not act as a radical scavenger that donates hydrogen atoms to the latter. The four consecutive harvest years studied indicated a clear declining trend in VOO SQ concentration upon olive ripening. To our knowledge, this is the first systematic work concerning the SQ content of Chondrolia Chalkidikis and Chalkidiki VOOs.

Influence of the Ripening Stage and Extraction Conditions on the Phenolic Fingerprint of 'Corbella' Extra-Virgin Olive Oil

The ancient ‘Corbella’ olive variety from the center-north of Catalonia is being recovered to obtain quality extra-virgin olive oil (EVOO) with unique organoleptic properties. The aim of this work was to determine the effect of agronomic and technical factors on the phenolic fingerprint of EVOO and to establish the optimum harvesting time and crushing and malaxation conditions for ‘Corbella’ olives. Therefore, three different ripening indices (0.3, 1.2, and 3.2) and three crushing temperatures (10, 18, and 25 OC) were studied. Additionally, a factorial design to optimize the phenolic concentration of the EVOO was developed, applying a range of sieve diameters (4 and 6 mm), and malaxation time (30 and 60 min) and temperature (27, 32, and 37 °C). The phenolic profile was analyzed by ultra-high performance liquid chromatography coupled to mass spectrometry in a tandem detector. The level of secoiridoids, the major phenolic compounds in the oil, was higher when using olives harvested earlier. Oleuropein aglycone and ligstroside aglycone were degraded during crushing at high temperatures, resulting in the formation of oleacein and oleocanthal. The best processing conditions in terms of total phenolic content were found to be 30 min of malaxation at 37 OC, the crushing size not having any affect.

Virgin Olive Oil Phenols, Fatty Acid Composition and Sensory Profile: Can Cultivar Overpower Environmental and Ripening Effect?

The authenticity and typicity of monocultivar oils and knowledge of the changes that environmental olive growing conditions bring to naturally present antioxidants and sensory attributes of virgin olive oils (VOO) are important for quality and safety improvement. This study delivers a comprehensive evaluation of the factors affecting phenolics, fatty acid composition and sensory characteristics of cultivars Oblica and Leccino VOOs throughout ripening season at two distinct olive growing environments during three consecutive crop years, and ranks the importance of each factor. Specified parameters were significantly influenced by olive growing environmental conditions. At the colder location of higher altitude, both cultivars gained higher amount of stearic, linoleic and linolenic fatty acids, as well as a higher proportion of phenolic compounds, but lower amounts of oleic fatty acid. At the warmer location of lower altitude, both cultivars had oils with lower level of fruitiness, bitterness and pungency. Analysis of the main components showed that VOOs were primarily differentiated by the cultivar, then main groups were divided with regard to the growing site, while harvest period affected the biosynthesis of natural VOOs antioxidants but had the least impact. These results reveal that the composition of fatty acids, phenolic content and sensory profile are predominantly characteristics of a cultivar.

A New Definition of the Term "High-Phenolic Olive Oil" Based on Large Scale Statistical Data of Greek Olive Oils Analyzed by qNMR

In the last few years, a new term, “High-phenolic olive oil”, has appeared in scientific literature and in the market. However, there is no available definition of that term regarding the concentration limits of the phenolic ingredients of olive oil. For this purpose, we performed a large-scale screening and statistical evaluation of 5764 olive oil samples from Greece coming from >30 varieties for an eleven-year period with precisely measured phenolic content by qNMR. Although there is a large variation among the different cultivars, the mean concentration of total phenolic content was 483 mg/kg. The maximum concentration recorded in Greece reached 4003 mg/kg. We also observed a statistically significant correlation of the phenolic content with the harvest period and we also identified varieties affording olive oils with higher phenolic content. In addition, we performed a study of phenolic content loss during usual storage and we found an average loss of 46% in 12 months. We propose that the term high-phenolic should be used for olive oils with phenolic content > 500 mg/kg that will be able to retain the health claim limit (250 mg/kg) for at least 12 months after bottling. The term exceptionally high phenolic olive oil should be used for olive oil with phenolic content > 1200 mg/kg (top 5%).

Characterization of virgin olive oils from Spanish olive varieties introduced in Mendoza, Argentina, and their comparison with the autochthonous variety

BACKGROUND

The aim of this work was to evaluate and compare oil production and its quality in three Spanish olive varieties (Genovesa, Villalonga, and Nevadillo blanco) growing outside the Mediterranean basin with the Argentine autochthonous variety (Arauco). Fruit parameters and oil characteristics were evaluated using samples collected from the germplasm collection of Mendoza province and elaborated in the same place.

RESULTS

The levels of phenolic compounds and the fatty acid composition of the samples were comparable with those previously published for these Spanish varieties, grown in the Mediterranean basin, showing the adaptability of olive trees. Observing the levels of phenolic compounds and oxidative stability, a strong correlation between oxidative stability and oleocanthal was observed.

CONCLUSION

The characteristics of the fruit and oil differed according to variety and season. The inter-harvest stability was different depending on the variety. Genovesa was observed to be the most stable variety according to its fruit and oil characteristics - even more stable than the autochthonous variety, Arauco. However, in terms of the composition of phenolic compounds, Arauco was the most stable between harvests, this characteristic being more important for the taste and uniformity of the product. © 2020 Society of Chemical Industry.

NMR-based metabolomic study of Apulian Coratina extra virgin olive oil extracted with a combined ultrasound and thermal conditioning process in an industrial setting

The innovative combination of ultrasound (Us) with a thermal exchanger to produce high quality extra virgin olive oil (EVOO) was studied using Nuclear Magnetic Resonance (NMR) spectroscopy and multivariate analysis (MVA). Major and minor metabolomic components of Apulian Coratina EVOO obtained using the two methods were compared. Early and late olive ripening stages were also considered. An increased amount of polyphenols was found for EVOOs obtained using the Us with respect to the conventional method for both early and late ripening stages (900.8 ± 10.3 and 571.9 ± 9.9 mg/kg versus 645.1 ± 9.3 and 440.8 ± 10.4 mg/kg). NMR spectroscopy showed a significant increase (P < 0.05) in polyunsaturated fatty acids (PUFA) as well as in the tyrosol and hydroxytyrosol derivatives, such as oleocanthal, oleacein, and elenolic acid, for both ripening stages. In conclusion, NMR spectroscopy provides information about the metabolomic components of EVOOs to producers, while the Us process increases the levels of healthy bioactive components.

Varietal and Geographical Discrimination of Greek Monovarietal Extra Virgin Olive Oils Based on Squalene, Tocopherol, and Fatty Acid Composition

Extra virgin olive oil (EVOO) is an important component of the Mediterranean diet and a highly priced product. Despite the strict legislation to protect it from fraudulent practices, there is an increasing demand to characterize EVOOs and evaluate their authenticity. For this purpose, 68 monovarietal EVOOs, originating from three regions of Greece (Peloponnese, Crete, and Lesvos) and two local cultivars (Koroneiki and Kolovi), were obtained during the harvesting period of 2018-2019. Fatty acids, squalene, and tocopherols were determined chromatographically according to official methods in order to study the effect of cultivar and geographical origin. Squalene and γ-tocopherol differed significantly amongst the cultivars tested. Koroneiki samples exhibited higher squalene content than Kolovi samples, whereas the opposite was observed for γ-tocopherol. The tocopherol level was highly geographical dependent, with EVOOs from Peloponnese displaying the highest concentration of α-tocopherol, whereas the content of γ-tocopherol was significantly higher in samples from Lesvos. Unsupervised and supervised multivariate analysis resulted in a satisfactory grouping of EVOOs according to cultivar. γ-Tocopherol, squalene, and the majority of fatty acids were the most discriminant variables, with γ-tocopherol, linoleic, linolenic, and gadoleic acid being present at higher levels in samples from the Kolovi cultivar. Koroneiki samples were characterized with higher levels of squalene, palmitic, palmitoleic, and arachidic acid.

Chemical Properties, Qualitative Parameters and Antioxidant Activity of Virgin Oil Obtained from Olea europaea Linn cultivar Zard Cultivated in Three Different Regions of Iran (Roudbar, Shiraz and Dezful)

Background:

Zard variety is a popular olive variety widely cultivated in different regions of Iran. Despite the extensive cultivation of this olive cultivar, little research has been carried out on its various properties. Thus, chemical properties, qualitative parameters and antioxidant activity of Olea europaea Linn cultivar Zard oil cultivated in three different regions including Roudbar, Shiraz and Dezful could be an interesting topic for research.

Methods:

After oil extraction of different olive samples, their different characteristics were compared. For this purpose, fatty acid composition, unsaponifiable matters, antioxidant compounds, qualitative parameters (acid value, peroxide value, carbonyl value, total polar compounds) Antioxidant activity assay (DPPH radical-scavenging assay and ferric reducing-antioxidant power (FRAP)) and oxidative stability index were measured.

Results:

Palmitic acid, oleic acid and linoleic acid contents in Zard variety cultivated in Roudbar (ZR), Zard variety cultivated in Shiraz (ZS) and Zard variety cultivated in Dezful (ZD) oils were 13.1, 15.2, 13.2; 72, 60.4, 68.8; 9.1, 17 and 12.2; respectively. The highest phenolic and tocopherol content was observed in ZD oil (90.4, and 160.2 mg/kg), followed by ZR (73.3, and 121.2 mg/kg) and ZS (52.2 and 67.5 mg/kg) oils. Evaluation of qualitative parameters in the oils revealed that they have suitable quality. Antioxidant activity assay indicated that ZD oil had the highest antioxidant activity, followed by ZR and ZS oils.

Conclusion:

Results of this investigation indicated that there was a direct relation between antioxidant activity and antioxidant content. Also, climatic difference in cultivation regions was a reason of significant difference in the properties of ZR, ZS and ZD oils.

Influence of Harvest Time and Malaxation Conditions on the Concentration of Individual Phenols in Extra Virgin Olive Oil Related to Its Healthy Properties

The phenolic fraction of the extra virgin olive oil (EVOO) has been studied over the past two decades because of its important health protective properties. Numerous studies have been performed in order to clarify the most crucial factors that affect the concentration of the EVOO’s phenolic fraction and many contradictory results have been reported. Having as target to maximize the phenolic content of EVOO and its healthy properties we investigated the impact of harvest time, malaxation temperature, and malaxation duration on the concentration of individual phenols in extra virgin olive oil. Olive oil was prepared in a lab-scale olive mill from different varieties in Greece. The extraction process for cultivar (cv) Koroneiki samples was performed at five different harvest periods from the same trees with three different malaxation temperatures and five different malaxation duration times (N = 75). Similar types of experiments were also performed for other varieties: cv Athenolia (N = 20), cv Olympia (N = 3), cv Kalamata (N = 3), and cv Throubolia Aegean (N=3) in order to compare the changes in the phenolic profile during malaxation. The quantitative analysis of the olive oil samples with NMR showed that the total phenolic content has a negative correlation with the ripening degree and the malaxation time. The NMR data we collected helped us to quantitate not only the total phenolic content but also the concentration of the major phenolic compounds such as oleocanthal, oleacein, oleokoronal, and oleomissional. We noticed different trends for the concentration of these phenols during malaxation process and for different malaxation temperatures. The different trends of the concentration of the individual phenols during malaxation and the completely different behavior of each variety revealed possible biosynthetic formation steps for oleocanthal and oleacein and may explain the discrepancies reported from previous studies.

Olive oil limited motor disruption and neuronal damage in parkinsonism induced by MPTP administration

Some vegetable oils show beneficial effects in modulating neurodegeneration; in this work, we evaluated the therapeutic potential of corn and olive oils against neurodegenerative processes using the acute parkinsonism murine model induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) in C57BL6 mice. The effects of corn and olive oils were quantified by the performance of mice in the open field and rotarod, and grasp strength tests and neuronal survival in the substantia nigra and striatum were determined by immunohistochemistry. Extra-virgin olive oil decreased the toxicity induced by MPTP administration judged by the performance in the behavioral motor tests and the number of total neurons in the analyzed brain regions. In contrast, corn oil only produced discrete changes in the behavioral and histological evaluations. Despite the numerous benefits of olive oil, its active substances that confer desirable effects and their mechanism of action remain unclear. Our observations can help to understand the ameliorative effects of some natural oils on neurodegeneration induced by some toxins, particularly the attenuation of neural damage related to toxin-induced parkinsonism or other pathologies that comprise neuronal death and motor disruption.

Olive oil characterization of cv. 'Arauco' harvested at different times in areas with early frost in Mendoza, Argentina

BACKGROUND

'Arauco' is the only autochthonous olive cultivar from Argentina. Little has been reported so far regarding the management of this crop. In this work, variations in fruit and chemical characteristics of olives harvested over a wide range of dates and seasons are reported for this cultivar at two sites in Mendoza province in central west Argentina.

RESULTS

During the harvest periods studied, fruit oil content on a dry basis remained at its maximum and was stable, but fruit oil content on fresh basis increased as water content decreased with delay in harvest date. Harvest date affected the maturity index of fruits as well as the oxidative stability and phenolic content of oil. In contrast, the fatty acid profile was not consistently affected by harvest date. Environmental conditions, mainly the occurrence and intensity of frosts, strongly influenced oil quality as well as maturity with delay in harvest date.

CONCLUSION

The most appropriate harvest time to obtain Arauco oil with a high oil yield and good chemical quality was before mid-May and with maturity index lower than 2. Fruits harvested after mid-May were exposed to minimum temperatures between -1.2 °C and - 4.0 °C, producing oil with low phenolic compounds and oxidative stability. © 2019 Society of Chemical Industry.

Could squalene be an added value to use olive by-products?

Squalene (SQ) is an intermediate hydrocarbon in the biosynthesis of phytosterols and terpenes in plants. It is widely used for applications such as skin moisturizers, vaccines, or in carriers for active lipophilic molecules. It has commonly been obtained from sharks, but restrictions on their use have created a need to find alternative sources. We present a review of studies concerning SQ in olive groves to characterize its content and to provide new aspects that may increase the circular economy of the olive tree. There is a large variation in SQ content in virgin olive oil due to cultivars and agronomic issues such as region, climate, types of soil, crop practices, and harvest date. Cultivars with the highest SQ content in their virgin olive oil were 'Nocellara de Belice', 'Drobnica', 'Souri', and 'Oblica'. An interaction between cultivar and aspects such as irrigation practices or agricultural season is frequently observed. Likewise, the production of high SQ content needs precise control of fruit maturation. Leaves represent an interesting source, if its extraction and yield compensate for the expenses of their disposal. Supercritical carbon dioxide extraction from olive oil deodorizer distillates offers an opportunity to obtain high-purity SQ from this derivative. Exploiting SQ obtained from olive groves for the pharmaceutical or cosmetic industries poses new challenges and opportunities to add value and recycle by-products. © 2019 Society of Chemical Industry.

Determination of the Oxidative Stability of Camellia Oils Using a Chemometrics Tool Based on 1H NMR Spectra and α-Tocopherol Content

This study, for the first time, predicts oxidative stability in camellia oils by partial least squares (PLS) built with proton nuclear magnetic resonance (¹H NMR) and α-tocopherol content. The prediction models were established by the PLS method. Outlier detection, latent variables optimization, data pretreatment, and important variables selection were applied for models optimization. All the developed models exhibited good performance as indicated by R² > 0.895 and root mean square error of estimation and root mean square error of prediction less than 0.322 and 0.307. For verification of the contribution of ¹H NMR spectra and α-tocopherol for prediction performance, a PLS model with fatty acids composition instead of ¹H NMR spectra and one with only ¹H NMR spectra as input variables were developed, respectively. The results showed that the model based on ¹H NMR data was more accurate and precise than that based on fatty acid composition data. And the performance of the models was significantly degraded without α-tocopherol as input variables.

Effect of Maturity and Environmental Conditions on Chemical Composition of Olive Oils of Introduced Cultivars in Morocco

This work aims at evidencing the quality and chemical composition of extra virgin olive oils according to stages of maturity and in relation to the geographical location of olives. Three different olive cultivars (Moroccan Picholine, Languedoc Picholine, and Frantoio), grown in two different locations in Morocco (Errachidia and Marrakech), were studied during the two crop years (2016 and 2017) at three stages of maturity (green, purple, and black). This work has been carried out by analyzing several parameters, such as the quality characteristics (acidity and peroxide value), the chemical composition (total phenol content and fatty acid composition) of the oils, and also the fruit characteristics of the olives (maturity index, fruit water content, and oil content). The results obtained in this study indicate that as maturity advanced, there was a slight rise in oil content and acidity, while there was a decrease in fruit water content and peroxide value in both locations during the two crop years. The fatty acid composition of extra virgin olive oil showed a significant increase of linoleic acid and polyunsaturated fatty acids (PUFAs) and a decrease of oleic acid, palmitic acid, monounsaturated fatty acids (MUFAs), and MUFA/PUFA ratio as the maturation process progressed. A significant gradual decrease was noted in total phenol content and bitterness intensity from the green stage to the black. Moreover, olive oil composition differed clearly between the two sites. Therefore, the olive cultivar, harvesting date, and geographic location influence the olive oil characteristics.

Volatile and Sensory Profiles of Algerian Extra-Virgin Olive Oil from Souidi and Zeletni Cultivars

In this study, the volatile and sensory profiles of monovarietal extra-virgin olive oil (EVOO) from two less widespread Algerian autochthonous cultivars (Souidi and Zeletni) were obtained using headspace solid-phase microextraction coupled to gas chromatography-mass spectrometry and a panel test, respectively. A total of 14 and 10 volatile compounds belonging to different chemical classes were identified and quantified in the Souidi and Zeletni EVOOs, respectively. Zeletni EVOO contains 2.07 times more (E)-2-hexenal than Souidi EVOO. In addition, the amounts of C6 compounds from LA and LnA, as well as the total amount of the compounds of the LOX pathway were higher in Zeletni than in the Souidi EVOO. Another important finding was the predominance of sesquiterpene β-ocimene in the composition of the volatile fraction of Souidi EVOO. The sensory profiles of the EVOOs analyzed were characterized by fruity, bitter and pungent sensory positive attributes, perceived at medium intensity in both oils studied.

Composition and Antioxidant Properties of Spanish Extra Virgin Olive Oil Regarding Cultivar, Harvest Year and Crop Stage

The health benefits of extra virgin olive oil (EVOO) are related to its chemical composition and the presence of bioactive compounds with antioxidant properties. The aim of this study was to evaluate antioxidant compounds (pigments, coenzyme Q₁₀ (CoQ₁₀) and phenolic compounds) and antioxidant properties of EVOO from the same region comparing different cultivars (Hojiblanca and Arbequina), harvest year and crop stage. Antioxidant properties of oils were studied before and after a gastrointestinal digestion process, by in vitro assays (DPPH, ABTS and FRAP) and antioxidant markers in Caco-2 cells (reactive oxygen species production). The content of bioactive compounds measured was significantly affected by cultivar and harvest year (except for carotenoids) and by the crop stage (except for coenzyme Q₁₀). Higher amounts of coenzyme Q₁₀ were observed in Hojiblanca than in Arbequina EVOO. Total phenol content and antioxidant properties were also different depending on cultivar and harvest year and the in vitro digestion process strongly improved antioxidant marker values. Antioxidant potential in bioaccessible fractions was mainly related to the content of coenzyme Q₁₀ and phenolic compounds in EVOO. Chemometric analysis showed that the oils were clearly classified by cultivars, harvest and crop stage, according to the chemical composition and antioxidant activity analyzed in the present study.

Oil Content, Fatty Acid and Phenolic Profiles of Some Olive Varieties Growing in Lebanon

Olive growing in Lebanon plays an important role at both a social and economic level. Nevertheless, the quality of olive oil produced in the country is rarely addressed. In this study, oil content, fatty acid, and phenolic profiles were studied along four different ripening stages for 11 varieties of olives, including two clones of the local variety “Baladi,” in addition to nine foreign varieties (“Ascolana Tenera,” “Bella di Cerignola,” “Itrana,” “Jabaa,” “Kalamata,” “Nabali,” “Salonenque,” “Sigoise,” and “Tanche”). Oil content was determined using the Soxhlet method and Abencor system. Fatty acid composition was determined using a GC-FID, total phenols using spectrophotometry, and the phenolic profile using HPLC-DAD. Results showed that variety, fruit ripening and their interaction have a significant effect on the overall studied oil parameters. Among the studied varieties, “Kalamata” presented the higher oil content on dry matter (OCDM = 48.24%), “Baladi 1” the highest oil content on humid matter (OCHM = 27.86%), and “Tanche” the highest oil industrial yield (OIY = 19.44%). While “Tanche” recorded the highest C18:1 (71.75%), “Ascolana Tenera” showed the highest total phenols (TP = 539 mg GAE/Kg of oil), “Salonenque” the highest oleacein (121.57 mg/Kg), and “Itrana” the highest oleocanthal contents (317.68 mg/Kg). On the other hand, oil content together with C18:2 and C18:0 increased along ripening while C18:1, total phenols and the main individual phenols decreased. Although preliminary, this study highlights the good quality of olive oil produced from both local and foreign varieties growing in Lebanon and encourages further investigations on the characterization and authentication of Lebanese olive oil.

LC-DAD-ESI-MS/MS-based phenolic profiling and antioxidant activity in Turkish cv. Nizip Yaglik olive oils from different maturity olives

The current study was designed to find out how olive maturity indices (2.5, 3.5, and 4.5) affect the individual phenolic compounds and antioxidant potencies of olive oils produced from cv. Nizip Yaglik olives. Liquid chromatography coupled to diode array detection and electrospray ionization tandem mass spectrometry in multiple reaction monitoring mode was utilized for the determination of phenolic composition qualitatively and quantitatively. Findings asserted a quite similar phenolic profile (14 phenols) depending on the various phenolic groups in all oils, while the concentration of total and individual phenolic compounds revealed significant differences between the samples statistically (p < 0.05). Among the individual phenolic classes in all samples, secoiridoids were the most prevailing group and their total content showed a clear significant decline as the olive fruits get ripened. Antioxidant potency values showed a clear diminution attitude during the maturation of the olives. The principal component analysis revealed that oils were discriminated from each other according to phenolic compounds and antioxidant potencies. Moreover, oils obtained from the unripe and medium-ripe fruits possessed a very good quality marked by their elevated phenolic levels.

Olive Leaf Addition Increases Olive Oil Nutraceutical Properties

The aim of the present research was to study the effects of olive leaf addition (0 and 3%) on the major antioxidants and the antioxidant activity of Neb Jmel and Oueslati olive oils. Olives and leaves of the two Tunisian varieties were harvested during the 2016/2017 crop season. Both leaves and oils were characterised for their concentrations in phenolics, tocopherols and antioxidant power. Other parameters such as free acidity, peroxide value, chlorophyll and carotenoid concentrations were also taken into consideration. Compared to Oueslati, the Neb Jmel oil showed a lower free acidity (50%) and peroxide value (5.6-fold), and higher chlorophyll (1.6-fold), total phenolics (1.3-fold), flavonoid (3-fold) and oleuropein derivative (1.5-fold) concentrations, in addition to an increased antioxidant activity (1.6-fold). Leaf addition promoted a significant increment in total chlorophyll, α-tocopherol and phenolics in both varieties, above all in Oueslati oil, due to a higher abundance of bioactive constituents in the corresponding leaves. In particular, chlorophyll and carotenoid concentrations reached values twice higher than in Neb Jmel leaves, and flavonoids and oleouperin derivatives were three-fold higher. This prevented the oxidation and the formation of peroxides, reducing the peroxide value of the fortified oil to the half. The results provide evidence on the performance of the Tunisian Neb Jmel and Oueslati varieties, showing that their oils present a chemical profile corresponding to the extra virgin olive oil category and that, after leaf addition, their nutritional value was improved.

Characterization of aroma, aroma-active compounds and fatty acids profiles of cv. Nizip Yaglik oils as affected by three maturity periods of olives

BACKGROUND

The present study aimed to investigate how olive maturity indices (MI) (2.5, 3.5 and 4.5 MI) affect the aroma, aroma-active compounds, fatty acid profiles and color properties of cv. Nizip Yaglik olive oils. Various techniques for extracting volatiles from oil materials are available in the literature. Aroma compounds were extracted by the solvent-assisted flavor evaporation extraction method for the first time in olive oil.

RESULTS

The type and number of aroma-active compounds varied according to maturity periods of olives. A total of 22, 21 and 20 different key odorants were found in aromatic extracts of samples with 2.5, 3.5 and 4.5 MI, respectively. The most potent aroma-active compounds based on flavor dilution (FD) factor values were hexanal (green) for 2.5 MI (FD: 1024) and 3.5 MI (FD: 512), as well as 1-penten-3-ol (green-leafy) for 4.5 MI (FD: 512).

CONCLUSION

Overall, olive oils obtained from unripe and medium-ripe olives had stronger green and fruity odours compared to ripe olives. Principal component analysis demonstrated that oils were clearly discriminated according to their general physicochemical analysis, fatty acids, aroma profiles and key odorants. The results of the present study show that the olive maturity period has a significant influence on the quality parameters of olive oil. © 2018 Society of Chemical Industry.

Fatty Acids and Phenolic Profiles of Extravirgin Olive Oils from Selected Italian Cultivars Introduced in Southwestern Province of Pakistan

Mediterranean olive trees have been cultivated in Pakistan for decades to promote olive cultivation and use of olive oil. The qualitative characteristics of seven mono and one multi-varietal extra virgin olive oils (EVOOs) extracted from Italian cultivars grown in different areas of Balochistan a southwestern province of Pakistan were evaluated. Present study aims to assess the impact of bioclimatological change on biochemical profile of exotic cultivars. The dominating fatty acids found in analyzed EVOOs were oleic (65-72%), linoleic (10.61-18.33%) and palmitic acids (12-16%). The tocopherols α, (β+γ) and δ contents showed a great diversity which ranged from (60-408) mg/kg while, total phenol concentration ranged from (200-370) mg/kg. The analyses of phenolic compounds revealed the presence of phenolic acids, phenolic alcohols, secoiridoids, flavonoids, oleuropein and verbascosides. One-way ANOVA revealed significant differences (p < 0.05) regarding studied parameters. Principal component analysis (PCA) was applied to identify the main components and to classify samples into groups in terms of fatty acids and phenolic profiles. The first group (Frantoio, Moraiolo, Pendolino, Multi-varietal mixture) characterized by high amount of oleic acid and MUFAs/PUFAs ratio. The second group (Maurino and Leccino) correlates with SFAs and third (Ottobrattica, Coratina) with PUFAs. Based on the PCA of phenolic profile the studied cultivars were divided into two main groups. Morialo, Pendolino and Maurino correlated with (phenolic acids, hydroxytyrosol, flavonoids and secoiridoids). Frantoio, Ottobrattica, Coratina, multi-varietal and Leccino were correlated with oleuropein, tyrosol and ligstroside aglycon. The obtained data was compared with those obtained from same cultivars in their original and/or different growing area. Marked differences were observed in the composition of oleic, linoleic, palmitic acids, secoiridoids and total phenolic contents. These differences could be due to change in geographical location and climatical condition of Balochistan. The cultivar Moraiolo has shown best adaptation and preserved its biochemical composition among all studied cultivars.

Chemical and Sensorial Characteristics of Olive Oil Produced from the Lebanese Olive Variety ‘Baladi’

The olive oil quality, nutritional and sensorial characteristics are associated with the chemical composition, which is the result of a complex interaction between several environmental, agronomical and technological factors. The aim of the present study is to investigate the impact of the geographical origin, harvesting time and processing system on the chemical composition and sensorial characteristics of olive oils produced from the Lebanese olive ‘Baladi’. Samples (n = 108) were collected from North and South Lebanon, at three different harvesting times and from four processing systems. Results showed a strong effect of origin, processing system and harvest time on oil quality, fatty acid composition, total phenols and OSI. The early harvest showed higher total phenols content (220.02 mg GAE/Kg) and higher OSI (9.19 h). Moreover, samples obtained from sinolea and 3-phases recorded the lowest free acidity (0.36% and 0.64%), and the highest OSI (9.87 and 9.84 h). Consumers were not unanimous regarding the studied factors, although samples recording high ranks were mostly from South using sinolea, 3-phases and press systems at early and intermediate harvest. The overall findings suggest that the selection of the harvesting time and of the processing system could have significant influence on the characteristics of the olive oil.

Continuous ethyl oleate synthesis by lipases produced by solid-state fermentation by Rhizopus microsporus

Lipases produced by solid-state fermentation were used directly as biocatalysts for continuous synthesis of ethyl oleate in a continuously stirred tank reactor. The effect of biocatalyst reutilisation, molar ratio of substrates, agitation rate and feed rate on the esterification of oleic acid with ethanol were investigated. The catalyst maintained 90% conversion for four batch cycles with a 1:2 molar ratio (oleic acid:ethanol). Mechanical agitation at 200 and 300 rpm during 12 h of continuous reaction did not affect the biocatalytic conversion, allowing substrate conversions greater than 90% that were obtained with 50 mM oleic acid at a molar ratio of 1:2 during 14 h reaction. In contrast, substrate conversion was 70% with 100 mM oleic acid at a flow rate of 2 mL/min during 25 h of reaction. These results are promising and offer a technical alternative for the development of accessible biocatalysts that can be used in continuous operations.