Contribution of olive seed to the phenolic profile and related quality parameters of virgin olive oil

BACKGROUND: Conflicting results have been reported about the effect of fruit de‐stoning on the virgin olive oil (VOO) phenolic profile. The aim of the present study was to determine whether olive seed plays any role in the synthesis of this oil phenolic fraction. RESULTS: Increases of around 25% of total phenolic compounds were observed in oils obtained from de‐stoned olive fruits in three main Spanish cultivars. To investigate the involvement of olive seed in determining the phenolic profile of VOO, whole intact olive fruits were added with up to 400% olive stones. Excellent regression coefficients were found in general for the decrease of total phenolic compounds and, particularly, of o‐diphenolics in the resulting oils. On the other hand, it was found that olive seed contains a high level of peroxidase (POX) activity (72.4 U g^?1 FW), accounting for more than 98% of total POX activity in the whole fruit. This activity is able to modify VOO phenolics in vitro, similar to the effect of adding stones during VOO extraction. CONCLUSION: Olive seed plays an important role in determining VOO phenolic profile during the process to obtain an oil that seems to be associated with a high level of POX activity. Copyright © 2007 Society of Chemical Industry     

Composition of total and esterified 4α-monomethylsterols and triterpene alcohols in virgin olive oil

Esterified 4α-monomethylsterols and triterpene alcohols were isolated from virgin olive oil by combined column chromatography-thin layer chromatography and their composition was assessed gas chromatographically using both packed and capillary columns. The compositions of the esterified 4α-monomethylsterol and triterpene alcohol fractions were compared with those of the total fractions which were isolated after saponification. Significant differences were observed between the distribution patterns of the total and esterified triterpene alcohol fractions, especially in the percentages of 24-methylenecycloartanol, butyrospermol and cycloartenol.     

Seasonal changes in olive fruit characteristics and oil accumulation during ripening process

Olive fruits of three of the most important Spanish and Italian cultivars, ‘Picual’, ‘Hojiblanca’ and ‘Frantoio’, were harvested at bi‐weekly periods during three crop seasons to study their development and ripening process. Fresh and dry weights and ripening index were determined for fruit, while dry matter, oil and moisture contents were determined in both fruit and pulp (flesh). Fruit growth rate and oil accumulation were calculated. Each olive cultivar showed a different ripening pattern, ‘Hojiblanca’ being the last one to maturate. Fruit weight increased, decreasing its growth rate from the middle of November. Dry matter and moisture contents decreased during ripening in pulp and fruit, ‘Hojiblanca’ showing the highest values for both. Oil content, when expressed on a fresh weight basis, increased in all cultivars, although for the last time period showed variations due to climatic conditions. During ripening, oil content on a dry weight basis increased in fruit, but oil biosynthesis in flesh ceased from November. Olive fruits presented lower oil and higher dry matter contents in the year of lowest rainfall. Therefore fruit harvesting should be carried out from the middle of November in order to obtain the highest oil yield and avoid natural fruit drop. Copyright © 2004 Society of Chemical Industry     

Effect of fruit stone removal on the production of virgin olive oil volatile compounds

To verify if the quantitative composition of volatiles arising from lipoxygenase pathway was affected by the olive fruit stones, oils from whole olives and from the pulp-only tissues, respectively, were submitted to gas chromatographic determination of volatile compounds extracted by dynamic head-space. Results showed different quantitative compositions for the two oil kinds because of the greater accumulation of C₆ compounds from the lipoxygenase pathway in oils obtained from de-stoned olives, which is related to serious cellular disruption observed in the crushed pulp tissues. C₅ compounds were affected by the stone removal from fruits. Furthermore, the enzymatic oxidation of linoleic acid was promoted in oils obtained after removing fruit stones because of the more significant increase of the concentrations of corresponding C₆ metabolites.     

Gas chromatographic–mass spectrometric characterisation of triterpene alcohols and monomethylsterols in developing Olea europaea L. fruits

Five triterpene alcohols and four 4-monomethylsterols were identified by GC–MS during the ripening of Picholine olive. The quantitative characterisation of these compounds was performed using GC–FID. The results showed that the maximum level of total triterpene alcohols (263.68 mg/100 g oil) was reached at 26th week after the flowering date (WAF) of olive; whilst the highest level of total 4-monomethylsterols (234 mg/100 g oil) was attained at 24th WAF of fruit. The percentage of these two classes represented 20–33% of total phytosterols during olive maturity. 24-Methylene cycloartenol (12–207 mg/100 g oil) and cycloartenol (27–198 mg/100 g oil) were the predominant triterpene alcohols during the ripening of Picholine olive; whereas citrostadienol (30–161 mg/100 g oil) and cycloeucalenol (11–74 mg/100 g oil) were the main 4-monomethylsterol compounds followed by obtusifoliol and gramisterol. β-Amyrin, δ-amyrin and traroxerol were less present in Picholine olive and they accounted for 14% of total triterpene alcohols at complete maturity of fruit. The level of these methylsterols was overwhelmed by the amount of 4-desmethylsterols at each stage of Picholine olive maturity.     

Saturated hydrocarbon content in olive fruits and crude olive pomace oils

Olive fruits contain an n-alkane series of saturated hydrocarbons mainly in the pulp. Lower amounts of a complex mixture of paraffins, unresolved by gas chromatography (UCM – unresolved complex mixture), have been found in cuticle, stone (woody shell and seed), olive leaves, and talc used as an aid to olive oil extraction. The amounts of both kinds of hydrocarbons are related to the olive cultivar and are transferred to oils in a proportion depending on the oil-obtaining process (centrifugation or solvent extraction). In olive oil obtained by centrifugation, only n-alkanes were detected. However, in olive oil extracted by second centrifugation, small amounts of UCM paraffins were detected together with the n-alkanes. Olive pomace oils showed a very variable content of both types of hydrocarbons according to the different obtaining process, such as double centrifugation, solvent extraction or centrifugation followed by solvent extraction. ‘White mineral oil’ used in oil extraction machinery is the source of the high concentrations of UCM paraffins found in some olive and olive pomace oils. In the case of second centrifugation olive oil, a maximum limit of 50 mg kg^?1 of UCM is suggested, whereas in the case of crude olive pomace oil, it amounts to 250 mg kg^?1 plus an additional minimum of 1.0 for the n-alkanes/UCM ratio.     

Detection of DNA in virgin olive oils extracted from destoned fruits

Characterization of genetic identity using DNA extracted from olive oil has the potential to facilitate assessment of origin and varietal conformity. Such a prospect is particularly interesting in light of the increased regional spread of olive cultivars and their various contributions to olive oil mixtures for certification of denomination of origin. Towards this goal, we have devised a reliable method for extracting DNA from virgin olive oil that was utilized on monovariety oils from the single, self-sterile cultivar ‘Ogliarola salentina’. We show that DNA purified from oil can be used for microsatellite analysis and that the profile of DNA purified from a monovariety oil corresponds to the profile of DNA purified from the leaves of the same cultivar. While DNA from the pollinators present in the genome of the seed embryo, could potentially contain alleles not present in the genome fruit pulp, invalidating the molecular traceability of olive oil, we show for the first time that there is no contamination of seed embryo DNA in a monovariety oil. Thus, this molecular assay is applicable for monovariety olive oils.     

Sensory and chemical profiles of three European olive varieties (Olea europea L); an approach for the characterisation and authentication of the extracted oils

Sensory data (1–16) as described by a trained panel, several characteristics (acidity, peroxide value, extinction coefficients at 232 and 270 nm, stability and phenolic compounds) (17–30) and chemical compositional data (fatty acids, sterols and triterpene diols, aliphatic and triterpene alcohols, and triglycerides) (31–67) were obtained for virgin olive oils of three European olive varieties, Coratina (Italy), Picual (Spain) and Koroneiki (Greece), at a certain stage of maturity—when half of the olives displayed partial or total purple colour—for two consecutive years of harvest, 1995–96 and 1996–97. The most remarkable characteristics for the classification of the oils were extracted using multivariate statistical analysis (correlation, hierarchical clustering and canonical discriminant analysis). Both sensory and/or chemical and quality characteristics were found to have significant potential for the authentication of the virgin olive oil varieties under investigation. © 2000 Society of Chemical Industry     

The glyceridic and nonglyceridic constituents of virgin olive oil after use of a novel method of enzyme extraction

Summary The composition of three virgin olive oil varieties (Caroleo, Coratina and Leccino) was investigated after extraction with a new enzyme processing aid called Bioliva. Comparisons with reference oils extracted without using the biological preparation were made. The oils extracted by enzymes showed the following features: (i) higher contents of total phenols, o‐diphenols, major free and hydrolysable phenols, tocopherols, chlorophylls, pheophytins (Mg‐free chlorophyll derivatives), β‐carotene, major xanthophylls (lutein, violaxanthin and neoxanthin), agreeable volatiles, long‐chain aliphatic alcohols and superior triterpene alcohols; (ii) lower contents of disagreeable volatiles; (iii) higher sensory scoring and resistance to autoxidation; (iv) higher values of Naudet's integral colour index, carotenoid colour index, chroma and 1,2‐diglycerides/1,3‐diglycerides ratio and (v) lower values of lightness. These findings suggested that the oil's analytical pattern was meaningfully improved following this novel enzyme treatment.     

Characterisation of phenolic extracts from olive pulp and olive pomace by electrospray mass spectrometry

Methanol extracts of olive pomace (two‐phase olive oil extraction) and olive pulp were analysed by reverse phase HPLC and the eluted fractions were characterised by electrospray ionisation mass spectrometry. This technique allowed the identification of some common phenolic compounds, namely, verbascoside, rutin, caffeoyl‐quinic acid, luteolin‐4‐glucoside and 11‐methyl‐oleoside. Hydroxytyrosol‐1′‐β‐glucoside, luteolin‐7‐rutinoside and oleoside were also detected. Moreover, this technique enabled the identification, for the first time in Olea europaea tissues, of two oleoside derivatives, 6′‐β‐glucopyranosyl‐oleoside and 6′‐β‐rhamnopyranosyl‐oleoside, and of 10‐hydroxy‐oleuropein. Also, an oleuropein glucoside that had previously been identified in olive leaves was now detected in olive fruit, both in olive pulp and olive pomace. With the exception of oleoside and oleuropein, the majority of phenolic compounds were found to occur in equivalent amounts in olive pulp and olive pomace. Oleoside was the main phenolic compound in olive pulp (31.6 mg g^?1) but was reduced to 3.6 mg g^?1 in olive pomace, and oleuropein (2.7 mg g^?1 in the pulp) almost disappeared (<0.1 mg g^?1 in the pomace). Both these phenolic compounds were degraded during the olive oil extraction process. Copyright © 2004 Society of Chemical Industry     

Essential oil,fatty acid and sterol composition of Tunisian coriander fruit different parts

BACKGROUND: Seed and pericarp of coriander fruit were compared in terms of essential oil, fatty acids and sterols. RESULTS: Essential oil yield of coriander samples ranged from 0.30 to 0.68% (w/w) in fruit and seed, respectively. However, in pericarp, the essential oil yield was only of 0.04% (w/w). Linalool was the major compound in the whole fruit, seed and pericarp, with 86.1%, 91.1% and 24.6% of the oils, respectively. Fatty acid composition of pericarp and seed lipids were investigated by gas chromatography. Petroselinic acid was the main compound of fruit and seed, followed by linoleic and oleic acids. Palmitic and linoleic acids were estimated in higher amounts in pericarp lipids. Total sterol contents were 36.93 g kg^?1 oil in seed, 6.29 g kg^?1 oil in fruit and 4.30 g kg^?1 oil in pericarp. Fruit and pericarp oils were characterized by a high proportion of β‐sitosterol, with 36.7% and 49.4% of total sterols, respectively. However, stigmasterol (29.5%) was found to be the sterol marker in seed oils. CONCLUSION: Coriander oil is a rich source of many compounds such as essential oils, fatty acids and sterols. This compound distribution presented significant differences between whole fruit, seed and pericarp. Copyright © 2009 Society of Chemical Industry     

Evaluating two kinds of centrifuged virgin oils arising from continuous olive processing

Oils extracted from olive pastes by the direct centrifugation mode were compared with the homologous oils produced by the indirect centrifugation (after percolation) mode. The former were characterised by: (i) higher contents of total phenols, o‐diphenols, hydroxytyrosol, hydroxytyrosol‐aglycons, total volatiles, trans‐2‐hexanal and other pleasant volatiles, total tocopherols, total sterols and waxes; (ii) lower contents of triterpene dialcohols, aliphatic and triterpene alcohols, chlorophylls and pheophytins; (iii) lower values of integral colour index; (iv) higher values of turbidity, campesterol/stigmasterol ratio, 1,2‐diglycerides/1,3‐diglycerides ratio, oxidative stability and overall quality indices; and (v) higher sensory score. Stigmastadienes and trans‐isomer C₁₈ fatty acids were always not detected. The average oil outputs of the two centrifugation extraction procedures were comparable, as confirmed by similar overall oil amounts found in the by‐products. © 2000 Society of Chemical Industry     

Sterolic composition and triacylglycerols of Oueslati virgin olive oil: comparison among different geographic areas

The main triglycerides (TG) identified in the Oueslati virgin olive oil were 1,2,3‐trioleylglycerol (OOO), 2,3‐dioleyl‐1‐palmitoylglycerol (POO) and 2,3‐dioleyl‐1‐linoleylglycerol (LOO) representing more than 80% of the total area of peaks in the chromatogram. Other minor triacylglycerols were 2,3‐dioleyl‐1‐stearoylglycerol (SOO), 2‐oleyl‐3‐palmitoyl‐1‐stearoylglycerol (SOP), 1‐linolenoyl‐2‐oleyl‐3‐palmitoylglycerol (LnOP), 1, 2‐dilinoleyl‐3‐palmitoylglycerol (LLP), 1, 3‐dioleyl‐2‐linolenoylglycerol (OLnO), 1‐linolenoyl‐2‐linoleyl‐3‐oleylglycerol (LnLO) and 1,2,3‐trilinoleylglycerol (LLL). The sterol profile of Tunisian virgin olive oils produced from Oueslati cultivar was established by gas chromatography using a flame ionisation detector (GC‐MS). More than 10 compounds were identified and characterised. As expected for virgin olive oil, the main sterols found in all Oueslati olive oils were β‐sitosterol, Δ5‐avenasterol, campesterol and stigmasterol. Cholesterol, 24‐methylenecholesterol, clerosterol, campestanol, sitostanol, Δ7‐stigmastenol, Δ5, 24‐stigmastadienol and Δ7‐avenasterol were also found in all samples, but in lower amounts. Most of these compounds are significantly affected by the geographical origin of the oil. Besides the sterol components, two triterpene dialcohols, erythrodiol and uvaol, were also detected.     

Comparison of fruit characteristics,oil properties and fatty acid composition of local Syrian Kaissy cv olive (<Emphasis Type="Italic">Olea europaea</Emphasis>)

Characterization of Syrian (Kaissy cultivar) olive fruits and evaluation of physic-chemical properties of oils were carried out during 3 years of production. The mean values of data for both measured and calculated variables of fruits were: grain length (21.89 mm), grain width (17.92 mm), length/width (1.22), weight of grain (3.79 g), weight of pulp (flesh) (3.19 g), weight of pit (0.60 g), pulp/pit ratio (5.35), crude oil (17.13%), water content (moisture) (51.34%). The 3 year average values of chemical properties of Syrian Kaissy cultivar olive oils (SKOO) including acid value, peroxide vale, Thiobarbituric acid value, iodine value(IV), saponification value, and phenolic content were 0.58%, 4.33 mEq O₂ kg^??1, 0.028 mg MDA kg^??1 oil, 90.77 g I₂, 100 g^??1, 194.91 mg KOH g^??1, and 218.08 g gallic acid kg^??1, respectively. Pefractive index (RI), and viscosity were 1.4666 nD at 25?°C and 139.56 mPa.s, respectively. However, the 2 years average values of Hunter’s color parameters of SKOO were; the lightness (L*= 66.91), redness (a* = 18.80), yellowness (b* = 29.08) and the color differences (?E?=?65.49). FA analysis of the SKOO used showed a high content of monounsaturated fatty acids (oleic acid 70.82% and palmitic acid 1.01%) and low polyunsaturated fatty acids (Linoleic acid 10.72% and Linolenic 0.82%) and saturated fatty acids (Palmitic 14.10% and stearic 2.57%). Results for 3 years production of Syrian Kaissy cultivar olive fruit and oil are discussed in detail.     

Composition and Quality of Pressed Virgin Olive Oils Extracted with a New Enzyme Processing Aid

ABSTRACT Virgin olive oils extracted with an enzyme complex were characterized with respect to the control oils by: (1) higher contents of major individual phenols (free + aglycons), o‐diphenols, total phenols, tocopherols, pleasant volatiles (including those from lipoxygenase pathway), green (chlorophylls and pheophytins) and yellow (carotenoids) lipochromes, higher aliphatic and triterpene alcohols, phytol, citrostadienol, triterpene dialcohols, and steroids; (2) lower contents of unpleasant volatiles and waxes; (3) highervalues of chroma, integral color index, and 1,2‐diglycerides/1,3‐diglycerides ratio; (4) higher sensory, bitter, spicy, and green fruit scorings; and (5) lower values of lightness and turbidity. The organophosphorus pesticide residues were usually not detected in the oils produced with or without enzyme.     

Oxidative stability of olive oil during the thermal process: Effect of Pistacia khinjuk fruit oil

The oxidative stability of refined olive oil with incorporated Pistacia khinjuk fruit oil (PKFO; 0.5%, 1%, 2%, 5%, and 10%) during thermal processing at 170ºC for 8 h was evaluated. The conjugated diene values, carbonyl values, acid values, oil/oxidative stability indices, and total tocopherol content were measured during thermal processing. Olive oil containing 0.5% PKFO was identified as the most oxidative stable oil followed by oils containing 100 ppm TBHQ and 1, 5, 10, and 2% PKFO. No significant difference between samples of olive oil containing 100 ppm TBHQ and 1% PKFO was observed. Thus, it was concluded that PKFO at levels lower than 1% could provide stronger antioxidation activity in comparison with TBHQ (the strongest syntactic antioxidant used in the food industry). Moreover, reduction in tocopherol compounds during thermal processing was higher in olive oil containing TBHQ as compared to those in pure olive oil.     

云南省不同引种地油橄榄果制取的油脂脂肪酸组成和角鲨烯含量分析

为了对云南省引种油橄榄优异种质资源提供理论依据,收集云南省不同引种地不同品种的油橄榄果,用索氏法提取橄榄油,通过气相色谱法测定其脂肪酸组成及角鲨烯含量。结果表明：不同引种地同一品种的橄榄油脂肪酸组成具有一定的相似性,大多聚于一类;不同品种橄榄油具有不同的脂肪酸组成,同一品种不同成熟度油橄榄果制取的橄榄油脂肪酸组成差异不大;不同品种橄榄油中角鲨烯含量变化幅度较大,最低值与最高值之间相差8.2 mg/g。综上,同一品种橄榄油的脂肪酸组成总体上具有一定的遗传稳定性,不同品种橄榄油具有不同的脂肪酸组成,且角鲨烯含量差异显著。     

固相微萃取-气质联用技术测定5种食用植物油挥发性成分

目的采用气相色谱-质谱(GC-MS)对大豆油、芝麻油、花生油、橄榄油、葡萄籽油5种食用植物油中挥发性成分进行分析。方法采用顶空固相微萃取(HS-SPME)技术对5种食用植物油中的挥发性成分进行萃取,并结合气相色谱-质谱(GC-MS)技术对挥发性成分进行测定。结果 5种食用植物油中共检测出101种挥发性化合物,其中大豆油11种、花生油28种、芝麻油65种、橄榄油25种、葡萄籽油5种。主要包括醛类、酯类、醇类、杂环类、酚类、酸类等10类物质。大豆油中主要的挥发性成分有戊醛、已醛和己酸,花生油中主要的挥发性成分有己醛、2,5-二甲基吡嗪和2,3-二氢苯并呋喃;芝麻油中主要的挥发性成分为5-甲基呋喃醛、2-吡咯甲醛、糠醇、愈创木酚、2-甲基吡嗪、2-乙基-6甲基吡嗪等;橄榄油中主要的挥发性成分为叶醇和4-己烯-1-醇乙酸酯;葡萄籽油中主要的挥发性成分为已醛。结论 5种食用植物油的挥发性物质的种类和含量上有很大区别,可为食用植物油的掺假鉴别提供参考依据。     

Chemical composition of virgin olive oils from Koroneiki cultivar grown in Tunisia with regard to fruit ripening and irrigation regimes

The impact of different irrigation regimes based on two ripeness index, on the quantity and quality of virgin olive oil from the introduced olive cultivar Olea europaea L. Koroneiki grown at a high‐density olive orchard in northern Tunisia, was assessed. Olive trees were subjected to three treatments (T1, T2 and T3) that received a seasonal water amount equivalent to 50%, 75% and 100% of the estimated local evaporative demand by a drip irrigation system and olives were collected in two different ripeness index. The olive oil content decreased when the water applied was increased but rose during ripening. The quality indexes and fatty acid composition were less affected by the irrigation schedule but most significantly by the maturity of olives. Moreover, phenol contents increased according to fruit ripening whereas no clear cut differences or consistent effects were observed by irrigation. α‐tocopherol decreased slightly in the oils as ripening progressed while insignificant differences between the irrigation treatments studied were obtained. Consequently, a restitution of 75% of crop evapotranspiration (ET_c.) was sufficient to achieve good minor compounds; however, higher water volumes (100% ET_c.) gave little additional α‐tocopherol and phenols increases.     

Synergistic effects of combinatorial Lactiplantibacillus plantarum fermentation and vegetable oils supplementation on the lycopene level,antioxidant capacities and flavor volatiles of tomato pulp

The objective of this study was to investigate the effects of Lactiplantibacillus plantarum (L. plantarum) fermentation and three types of vegetable oils (corn oil, peanut oil, and olive oil) supplementations on the physicochemical properties, bioactive components, and flavor volatiles of tomato pulp. Tomato pulp supplemented with oils was excellent food matrices for L. plantarum growth, and the colony counts remained above 8.3 log CFU/mL at the end of fermentation. The contents of total phenol, carotenoids and lycopene were dramatically increased after fermentation, and oils supplementation exhibited a synergistic promotion effect, especially for the combination of L. plantarum fermentation and 3% olive oil supplementation exhibiting the highest lycopene level (30 mg/mL), the strongest DPPH radical scavenging activity (84.24%) and FRAP (16.45 mmol Trolox/L). Furthermore, synergistic L. plantarum fermentation and oils supplementation decreased aldehydes content, and increased alcohols, esters, and ketones formation, meaning the improved flavor characteristics of fermented tomato pulp.Industrial relevanceIn this study, a functional beverage of tomato pulp was prepared by the combination of L. plantarum fermentation and vegetable oils supplementation. Colony counts, lycopene level, antioxidant capacities, and flavor characteristics were dramatically improved at the end of fermentation. This study provides an innovative technology to improve the release of lycopene from plant tissue and provide a functional beverage of tomato pulp with high health benefits.