Cultivar and growing area effects on minor compounds of olive oil from autochthonous and European introduced cultivars in Tunisia

BACKGROUND: Antioxidant profile and volatile compounds were characterized in three virgin olive oils from European countries introduced and cultivated under the same orchard conditions in comparison to some autochthonous cultivars planted in different areas of Tunisia. RESULTS: Significant differences were observed between the oils. α‐Tocopherol content is more important in autochthonous Tunisian cultivars (cvs), higher (400 mg kg^?1) than in European cvs. Total phenols showed that Chétoui cv. (grown in Zaghouan) had the highest level (446 mg kg^?1), followed by Koroneiki (403 mg kg^?1) and Chétoui cvs (grown in Béja) (398 mg kg^?1). Koroneiki oils had the highest content of (3,4‐dihydroxyphenyl)ethanol and (p‐hydroxyphenyl)ethanol (20.5 and 43.5 mg kg^?1, respectively), whereas (3,4‐dihydroxyphenyl)ethanol was not detected in Arbequina, Arbosana or Chemlali cvs (grown in Sahel). Chétoui cv. presented the highest content of dialdehydic form of decarboxymethyl elenolic acid linked to (3,4‐dihydroxyphenyl)ethanol (171 mg kg^?1), whereas Chemlali (Sahel) cv. had the lowest content (29.6 mg kg^?1). The volatile compounds showed an increase in C6 compounds and decrease in pentene isomers in olive oils from varieties cultivated in other growing areas. CONCLUSION: Virgin olive oils studied demonstrate that the differences in phenols, tocopherol levels and volatile profiles may be explained by genetic factors and geographic areas, particularly altitude. Copyright © 2009 Society of Chemical Industry     

Influence of the microencapsulation on the quality parameters and shelf-life of extra-virgin olive oil encapsulated in the presence of BHT and different capsule wall components

The main goal of this study was to assess the influence of the microencapsulation on the oil chemical composition and its oxidative stability. Factors such as microcapsule wall constituents and the addition of the antioxidant butylhydroxytoluene (BHT) were investigated in order to establish the most appropriate conditions to ensure no alteration of the extra-virgin olive oil chemical characteristics. The microencapsulation effectiveness was determined in base of process yield and the microencapsulation efficiency. Highest encapsulation yields were achieved when maltodextrin, carboxymethylcellulose (99.79 ± 0.51%) and lecithin were used as encapsulation agents and the ratio of oil-wall material was 1:1.5. Stability studies were achieved by placing encapsulated oil and un-encapsulated oil in heated chambers at 30 °C during 4 months. Oxidative stability and oil quality studies were periodically assessed. It was concluded that the presence of protein constituents in the microcapsule wall material extended the shelf-life of the microencapsulated olive oil (protein-based model microencapsulated oil was unalterable for 9 to 11 months). For this later model, the addition of antioxidant additives did not significantly increase the oil stability.     

Contribution of minor compounds to the singlet oxygen-related photooxidation of olive and perilla oil blend

This study evaluated contribution of natural minor compounds including carotenoids, tocopherols, polyphenols, and phosphatidylcholine (PC) to the stability of chlorophyll sensitized oxidation of olive and perilla oil blend under 2,500 lx light at 25°C for 48 h. The oxidation of the oil blend was evaluated by headspace oxygen consumption and peroxide values (POV). Minor compounds were also monitored. The headspace oxygen consumption and POV of the oil blend were increased with oxidation time; however, fatty acid composition was not significantly changed. Carotenoids, tocopherols, polyphenols, and PC were degraded during the oil oxidation, which was closely related with their singlet oxygen quenching. Correlations of the oil oxidation were higher with contents of carotenoids and PC (r ²>0.93) than with those of tocopherols or polyphenols, suggesting high contribution of carotenoids and PC to decreasing singlet oxygen-related photooxidation of olive and perilla oil blend.     

成熟度指数对不同品种橄榄油脂肪酸、 酚类化合物及风味属性的影响

以甘肃省陇南市油橄榄研究所种质资源基因库的‘城固32号’和‘莱星’油橄榄果为原料提取橄榄油,运用GC-MS、HPLC和E-Nose对不同品种与不同成熟度指数的橄榄油脂肪酸、酚类化合物及风味属性进行检测分析,以探究成熟度指数与不同品种橄榄油品质的关系。结果表明：随着成熟度指数的增大,‘城固32号’橄榄油中的硬脂酸、油酸、亚麻酸、饱和脂肪酸（SFA）含量及单不饱和脂肪酸/多不饱和脂肪酸（MUFA/PUFA）和油酸/亚油酸值呈下降趋势,亚油酸和不饱和脂肪酸（UFA）含量呈上升趋势,‘莱星’橄榄油中油酸和UFA含量及MUFA/PUFA和油酸/亚油酸值呈上升趋势,而亚油酸、亚麻酸和SFA含量呈下降趋势;油酸/亚油酸和MUFA/PUFA值在2个品种间存在差异,可作为鉴别‘城固32号’和‘莱星’橄榄油的依据;2个品种橄榄油中酪醇和总酚含量总体呈下降趋势,香草酸和木犀草素含量总体呈上升趋势,而羟基酪醇含量在‘城固32号’中总体逐渐减少,在‘莱星’中总体逐渐增加,木犀草苷含量在2个品种中保持稳定;风味物质的E-Nose信号响应值在2个品种中均显著减小。利用橄榄油中脂肪酸和酚类化合物的组成与含量以及风味属性的信号响应值差异结合主成分（PCA）分析可有效鉴别和区分不同成熟度指数的‘城固32号’和‘莱星’橄榄油。     

Determination of phenolic and other polar compounds in flaxseed oil using liquid chromatography coupled with time-of-flight mass spectrometry

A new method based on high-performance liquid chromatography coupled with electrospray ionisation time-of-flight-mass spectrometry (HPLC–ESI–TOF (MS)) has been used to analyse phenolic compounds in flaxseed oil. Some phenolic compounds such as secoisolariciresnol, ferulic acid and its methyl ester, coumaric acid methyl ester, diphyllin, pinoresinol, matairesinol, p-hydroxybenzoic acid, vanillin and vanillic acid have been detected from flaxseed oil. The quantification of these compounds in three varieties of flaxseed oils was carried out using their commercial standards. The efficiency, rapidity and high resolution of HPLC coupled to the sensitivity, selectivity, mass accuracy and true isotopic pattern from TOF (MS) have revealed an enormous separation potential allowing the determination of a broad series of phenolic and other polar compounds present in flaxseed oil for the first time.     

Microwave heating of different commercial categories of olive oil: Part I. Effect on chemical oxidative stability indices and phenolic compounds

The effect of microwave heating of extra virgin olive oil (EVOo), olive oil (Oo) and pomace olive oil (Po) in domestic appliances, was investigated in terms of chemical oxidative indices (peroxide, p-anisidine and Totox values), free acidity, water content, total phenol content and different classes of phenolic compounds.     

The potential of different techniques for volatile compounds analysis coupled with PCA for the detection of the adulteration of olive oil with hazelnut oil

This paper investigates the effectiveness of three rapid methods of volatile compounds analysis with subsequent principal component analysis (PCA) treatment of data for differentiation between virgin olive oil samples adulterated with hazelnut oil. Tested methods included comparison of chromatograms of volatiles obtained using SPME-fast GC-FID, volatiles analysis by electronic nose based on MOS sensors (HS-Enose), and by direct coupling of SPME to MS (SPME-MS). Volatile compounds were analyzed also by SPME-GC/MS technique. Data obtained as a result of SPME-GC/MS was subjected to PCA. SPME-GC–MS analysis with subsequent PCA yielded good results, however being time consuming. The three methods of analysis of volatiles, with subsequent PCA treatment of data, allowed detection of olive oil adulteration with different contents of hazelnut oil ranging from 5 to 50% (v/v).     

Exploratory chemometric analysis for the characterisation of Tunisian olive cultivars according to their lipid and sterolic profiles

This study aims to evaluate some Tunisian olive genetic resources using fatty acid, triacyglycerol and sterolic compositions and to classify the cultivars according to their fruit genotype and to their respective geographical origin (North, Centre and South). manova results showed that the studied cultivars presented highly significant differences regarding all the variables (P < 0.01). The most discriminant variables of fatty acids are C17:1 (F = 98.468), C16:0 (F = 92.994), C18:1 (F = 60.865), C18:1/C18:2 (F = 44.632) and C18:2 (F = 40.167); those of triacylglycerols are POP (F = 123.34), LLL (F = 122.944), LnLO (F = 98.363), POO (F = 93.357) and LOO (F = 90.42), while sitostanol (F = 289.171), campestanol (F = 192.792) and campesterol (F = 160.724) have the higher discriminant power among sterol compounds. Principal component analysis (PCA) was performed on the data of each chemical parameter to explore their usefulness for the discrimination of eleven monovarietal olive oils. Best differentiations among cultivars were obtained with triacyglycerol and sterolic compositions. The spatial distribution of the different oil samples using all the collected data showed a good discrimination among olive cultivars. A strong resolution between the samples according to the geographical origin was obtained by means of factorial discriminant analysis (FDA) (λ = 0.002). Comparisons of the distances between classes were statistically significant (Fisher tests; P < 0.0001), and 90.91% of cross‐validated grouped cases are correctly classified. The obtained results could become an important tool for sorting out oils to a single cultivar or to a specific geographical area.     

Characterisation of the phenolic compounds retained in different organic and inorganic filter aids used for filtration of extra virgin olive oil

The aim of this work was to identify and quantify some of the phenolic compounds retained by different filters used for the filtration of two varieties of extra virgin olive oil (Arbequina and Picual). This was performed by HPLC–ESI–TOF and Folin–Ciocalteau spectrophotometric technique. A significant loss in the phenolic concentration with all the tested filter aids was observed. This suggests that the organic filter aids present a higher performance than traditional industrial filters on a laboratory scale, although they show more retentive power regarding the phenolic concentration.     

Surface properties of phenolic compounds and their influence on the dispersion degree and oxidative stability of olive oil O/W emulsions

The surface and interfacial properties of gallic acid, catechin and quercetin, and their effect on the dispersion degree and the oxidative stability of olive oil oil-in-water (O/W) emulsions prepared using β-lactoglobulin and Tween 20 were studied.Gallic acid showed no effect on the surface properties while catechin was proven to be able to accumulate at the air/water interface, decreasing the surface tension values with increasing its concentration. All the phenolic antioxidants caused a decrease in the interfacial tension at the oil/water interface, even though only catechin and quercetin showed a concentration dependent behaviour.In emulsions, gallic acid did not affect the droplet size of the systems, catechin caused the formation of oil droplets bigger than those of the control, whilst quercetin improved the dispersion state of the emulsions with the increasing of its concentration. Gallic acid, despite its partitioning in the water phase due to its polarity, delayed the formation of both the hydroperoxides and TBARs and limited their accumulation. Catechin did not affect the formation of oxidation products whilst quercetin, among the tested antioxidants, caused the lowest formation of both hydroperoxides and TBARs through 33 days of storage.     

Variation of pyranoanthocyanins in red wines of different varieties and vintages and the impact of pinotin A addition on their color parameters

The present study evaluates the influence of pyranoanthocyanins on the color of German red wines (Dornfelder, Cabernet Sauvignon, and Pinot Noir) from different vintages from 1996 to 2006. The wines were spiked with a solution of pinotin A raising the natural pyranoanthocyanin concentration in the wine by 2, 5, 8, 10, and 15 mg/L. The color parameters were determined by spectroscopy and the spiked wines were presented to a sensory panel in a 3-alternative forced choice (3-AFC) test for color evaluation. The comparison of treated and untreated wines clearly demonstrated that the influence of pinotin A on the overall perceived color in these red wines was not significant. The 3-AFC test showed no significant difference between Dornfelder and Cabernet Sauvignon wines, due to the increase of pinotin A. Solely in the case of some aged Pinot Noir wines small effects (i.e., strong decrease of lightness and low decrease of chromaticity) were apparent, which could be shown to be due to the dilution of the sample caused by the added pinotin A solution.     

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     

Composition of total sterols (4-desmethyl-sterols) in extravirgin olive oils obtained with different extraction technologies and their influence on the oil oxidative stability

The composition and antioxidant activity of total sterols in extravirgin olive oils obtained with different extraction technologies from olives harvested at two ripening stages, were studied. The antioxidant activity was evaluated with an oxidative stability instrument (OSI), by using a model system (made of a mixture of treated/untreated commercial refined peanut oil) enriched with the total sterol fractions of the extravirgin olive oils. No correlation was found between the OSI time and the extraction technologies, the ripening stages or the actual amount of sterols added. No significant differences were observed in the percent composition of sterols of extravirgin olive oils produced with different technologies during the same harvesting period. The latter, however, had a significant effect on the percent of β-sitosterol and 5-avenasterol in extravirgin olive oils produced with the same technology.     

Emerging opportunities for the effective valorization of wastes and by-products generated during olive oil production process: Non-conventional methods for the recovery of high-added value compounds

BackgroundA large amount of wastes and by-products are generated during olive oil production process. Traditionally, these products have been considered as a problem. However, they constitute a great source of high-added value compounds, which have the potential to be used as food additives and/or nutraceuticals. Therefore, valorization of wastes and by-products from food industry kills two birds with one stone and addresses both the use of waste and by-products and societal health, thus greatly contributing for a sustainable food chain from an environmental and economical point of view.Scope and approachIn the present review, current and new insights in the recovery of high-added value compounds from wastes and by-products generated during olive oil production process will be discussed. Several conventional (solvent, heat, grinding) and non-conventional methodologies (ultrasounds, microwaves, sub- and supercritical fluid extractions, pressurized liquid extraction, pulsed electric fields and high voltage electrical discharges) have been investigated for the recovery of high-added value compounds (polyphenols, fatty acids, coloring pigments (chlorophylls and carotenoids), tocopherols, phytosterols, squalene, volatile and aromatic compounds) from wastes and by-products generated during olive oil production process.Key findings and conclusionsNon-conventional technologies can constitute a promising tool to recover high-added value compounds from olive oil wastes and by-products. However, the content of these valuable compounds can vary greatly depending on the matrix and the efficiency in the recovery of these compounds is highly dependent of the technology used for extraction.     

A potentiometric electronic tongue for the discrimination of honey according to the botanical origin. Comparison with traditional methodologies: Physicochemical parameters and volatile profile

The effectiveness of a potentiometric electronic tongue, made of various metals and metallic compounds was evaluated for the differentiation of honey in three different states: raw, liquefied and pasteurized. Principal component analysis (PCA) and a neural network showed that potentiometric electrodes seem useful to classify honey by its botanical origin, though they do not seem capable of discrimination between applied thermal treatments. The same was observed in the samples for physicochemical parameters and volatile compounds analysed with PCA. Au, Cu and Ag electrodes were more decisive in the discrimination of honey. A remarkable correlation (PLS analysis) between the electronic tongue and the physicochemical parameters was found, the best results being for color Pfund (r² = 0.958), L^∗ (r² = 0.935) and diastase activity (r² = 0.926). The correlation with volatile compounds was much weaker, though this improved for specific characteristic compounds in each monofloral variety. Thus, this is a good starting point for the development of new systems focused on the honey sector.     

Two by-products of the olive oil extraction industry as oleic acid supplement source for Iberian pigs: effect on the meat's chemical composition and induced lipoperoxidation

BACKGROUND: The objective of the present study was to evaluate the effect of two by‐products of the olive oil extraction industry—olive soapstocks and olive‐pomace oil—as added fat sources into feed concentrates, in two different rearing systems (free‐range complemented with concentrates and intensive rearing with concentrates) on the chemical composition and oxidative stability of Iberian pig meat. RESULTS: No differences in the chemical composition, colour and fatty acid composition of gluteobiceps m. were found due to added fat source. However, the feeding system had a significant effect on protein (P < 0.05), γ‐tocopherol (P < 0.05), colour (P < 0.01) and fatty acid composition of gluteobiceps m. Neither added fat source nor the feeding system had an effect on the malondialdehyde content. CONCLUSION: The addition of olive soapstock or olive‐pomace oil as fat sources into concentrates did not influence meat composition or fatty acid profile. However, there are differences in the fatty acid composition of meat from Iberian pigs as a result of the production system used. Copyright © 2012 Society of Chemical Industry     

Comparative studies on the antioxidant properties and polyphenolic content of wine from different growing regions and vintages,a pilot study to investigate chemical markers for climate change

Many health benefits of wine result from specific polyphenolic compounds. Factors such as climate, CO₂ levels and region are known to affect polyphenolic compounds in wine; therefore a pilot study was conducted to focus on the Australian climate which has shifted from El Niño to La Niña. This research paper presents the influence of climate conditions and growing regions on the in vitro and ex vivo antioxidant capacity of red and white wine and the profile and concentration of polyphenols in these wines from the 2008 and 2009 vintages. The ORAC and polyphenolic data show that warmer climate wines had lower in vitro antioxidant capacity values but retained good bioavailability based on data from the RBC ex vivo assay compared to cool climate wines. Based on this pilot study, further research is being conducted at the National Measurement Institute, Australia (NMIA) with the goal of determining more polyphenolic compounds which appear to be affected by climate conditions.