In vitro bioaccesibility of lutein and zeaxanthin from the microalgae Scenedesmus almeriensis

Aim of the study

To assess the in vitro bioaccessibility of lutein and zeaxanthin from lyophilised biomass and lutein-enriched extracts in olive oil produced from a lutein overproducing strain of Scenedesmus almeriensis.

Results

Lutein and zeaxanhin were mostly present in free form (>90–95%). Both xanthophylls were highly stable upon in vitro digestion, with an overall recovery above 75% (lyophilised biomass) and very low isomerization, whilst micellarization was <1% of the amount initially present and cis-isomers of lutein and β-carotene were preferentially incorporated. Using lutein-enriched extracts in olive oil, the micellarization of lutein and zeaxanthin increased dramatically reaching values up to 80–90% of the amounts initially present.

Conclusion

The lyophilised biomass of S. almeriensis constitutes a very rich source of free lutein (and zeaxanthin) but poorly bioaccesible. However, oil extracts from this lyophilised biomass are highly bioaccesible and may supply amounts of lutein and zeaxanthin comparable to or higher than those provided by traditional foods.     

Efficient Extraction of Olive Pulp and Stone Proteins by using an Enzyme‐Assisted Method

An efficient protein extraction protocol for proteins from olive pulp and stone by using enzymes was developed. For this purpose, different parameters that affect the extraction process, such as enzyme type and content, pH, and extraction temperature and time, were tested. The influence of these factors on protein recovery was examined using the standard Bradford assay, while the extracted proteins were characterized by sodium dodecyl sulfate?polyacrylamide gel electrophoresis (SDS‐PAGE). The best extraction conditions were achieved at pH 7.0 and 5% (v/v) Palatase® 20000 L (lipase) for pulp and Lecitase® Ultra (phospholipase) for stone proteins. The optimal extraction temperature and time were 30 and 40 °C for 15 min for pulp and stone tissues, respectively. Under these conditions, several protein extracts coming from olive fruits of different genetic variety were analyzed, their profiles being compared by SDS‐PAGE. The developed enzyme‐assisted extraction method showed faster extraction, higher recovery, and reduced solvent usage than the nonenzymatic methods previously described in the literature. In the case of stone proteins, different electrophoretic profiles and band intensities were obtained that could be helpful to distinguish samples according to their genetic variety.     

Identification of a new phenolic compound from Chinese olive (<Emphasis Type="Italic">Canarium album</Emphasis> L.) fruit

Chinese olive (Canarium album L.), a native and a well-known tropical fruit tree in the southeast of China, contains large amount of phenolics and possesses great pharmacological activities. In this study, phenolics were extracted from Chinese olive fruit pulp using 80% (v/v) aqueous acetone, and acetone extracts were further fractioned with petroleum ether, ethyl acetate and n-butanol sequentially. From n-butanol fraction, a new phenolic compound was isolated and purified through AB-8 adsorption resin column chromatography, polyamide column chromatography and TSK Toyopearl HW-40 (S) column chromatography, and the structure of the new compound was established as 3-O-galloyl quinic acid butyl ester by electrospray ionization mass spectrometry (ESI-MS), 1D- and 2D-NMR (DEPT, COSY, HMBC, HMQC) and UV–vis techniques.     

A rapid screening for adulterants in olive oil using DNA barcodes

A distinctive methodology is developed to trace out the mixing into olive oil, which is marketed every year with 20% or more fraudulent oils. Such adulteration has been difficult to differentiate using fatty acid analysis and other available current techniques, as chemically fatty acids are same regardless of their source. The total genomic DNA isolated from olive oil, contaminated with canola and sunflower was analysed for single nucleotide polymorphism (SNP) variation in noncoding spacer region between psbA-trnH and partial coding region of matK of plastid genome. These DNA regions were amplified by PCR using specific primers and resulting DNA sequences were matched to the predetermined consensus DNA barcode sequences of canola and sunflower for discerning the contaminations in olive oil samples. The matching of an adulterant DNA sequence with their respective DNA barcode revealed the mixing of canola and sunflower oil into olive is simpler way and the combined approach of molecular biology and bioinformatics technology can be used as an inexpensive method for ensuring the purity of olive. This plastid based molecular DNA technology can be used for rapid detection of adulteration easily up to 5% in olive oil.     

On the monitoring of carotenogenesis by Blakeslea trispora using HPLC

A rapid, isocratic RP-HPLC method for the determination of the carotenoids produced by Blakeslea trispora is described. The mixture of acetone:acetonitrile, 60:40, v/v, found appropriate for the cellular triacylglycerol analysis, was also successfully used for the separation of lycopene, γ-carotene and β-carotene. The method was validated for β-carotene using an olive oil triacylglycerol fraction devoid of carotenoids. Recovery study (300 mg/kg oil) was 99%. RSDr and RSD_L were satisfactory (<4%). The limit of quantification was found to be 4.56 ng/5 μL and the system was linear in the range 2.0–30.0 ng/μL.     

Waxy fraction containing long-chain aliphatic aldehydes in virgin olive oils

Long-chain aliphatic aldehydes are natural minor components occurring in the cuticle of numerous plant species and also evidenced in virgin olive oils. The fraction containing these compounds can be isolated from the oil samples by using a solid-phase extraction silica-gel cartridge and then directly analysed by GC on a 5% diphenyl-95% dimethylsiloxane capillary column, using an on column-injection system. The proposed methodology showed that extra virgin olive oils contain long-chain aliphatic aldehydes, with even carbon-atom numbers from C₂₂ to C₃₀. Quantitative results, using the synthesised aldehyde C₂₁ as internal standard, give concentrations of total long-chain aliphatic aldehydes in a variable range below 116 mg kg⁻¹, being hexacosanal (C₂₆-al) the most abundant aldehyde. The different experimental conditions utilised during olive oil extraction processes influence the total aldehydes concentration. Besides contribution to the knowledge of the minor-component composition present in olive oil, their interest and relationship with wax esters, aliphatic alcohols and n-alkanes are discussed.     

Proteins in Olive Fruit and Oil

This paper is a comprehensive review grouping the information on the extraction, characterization, and quantitation of olive and olive oil proteins and providing a practical guide about these proteins. Most characterized olive proteins are located in the fruit, mainly in the seed, where different oleosins and storage proteins have been found. Unlike the seed, the olive pulp contains a lower protein content having been described a polypeptide of 4.6 kDa and a thaumain-like protein. Other important proteins studied in olive fruits have been enzymes which could play important roles in olives characteristics. Part of these proteins is transferred from the fruit to the oil during the manufacturing process of olive oil. In fact, the same polypeptide of 4.6 kDa found in the pulp has been described in the olive oil and, additionally, the presence of other proteins and enzymes have also been described. Protein profiles have recently been proposed as an interesting strategy for the varietal classification of olive fruits and oils. Nevertheless, there is still a lot of knowledge without being explored requiring new studies focused on the determination and characterization of these proteins.     

Sterol and alcohol components of seed,pulp and whole olive fruit oils. Their use to characterise olive fruit variety by multivariates

Sterols, triterpene dialcohols, long‐chain aliphatic alcohols and higher triterpene alcohols were determined in three fruit oil kinds (seed, pulp and whole fruit oils). Seven major Italian olive fruit varieties from the same environment were considered. Results of this research suggested that the compositional data concerning the above analytical fractions were effective in discriminating between seed and pulp oils. The seed oil fraction did not substantially modify the sterol and alcohol composition of the whole fruit oil (mixture of seed and pulp oils), the percentage weight of the seed (～2%) being far lower than that of the pulp (～85%) (whole fruit weight basis). Based on the concentrations of the above components and using appropriate statistical parametric or non‐parametric multivariate techniques, the genetic origin (olive variety) of the three fruit oil kinds was characterised. © 2002 Society of Chemical Industry     

Discrimination of five Tunisian cultivars by Mid InfraRed spectroscopy combined with chemometric analyses of olive Olea europaea leaves

The high biodiversity of olive tree and the economic needs require tools for the correct classification and identification of the different cultivars. Simple and rapid methods are in increasing demand. In the present work, FT-MIR spectroscopy associated to chemometric treatment is proposed as a direct and rapid tool to discriminate cultivars according to their olive leaves, a persistent tissue the whole year. A set of 75 samples of olive leaves representative of five Tunisian cultivars (Chemlali, Sayali, Meski, Zarrazi and Chétoui) cultivated in the same geographical area was analysed. Discrimination between the five Tunisian cultivars was performed by the chemometric approach, principal component analysis (PCA), based on the FT-MIR spectral data provided by olive leaves. Furthermore, a correct classification (100%) of the five Tunisian cultivars was obtained by the Partial Least Square Discriminate Analysis (PLS-DA) method.     

The type and quantity of lipids present during digestion influence the in vitro bioaccessibility of lycopene from raw tomato pulp

This study elucidates the impact of the type and quantity of lipids, added upon digestion of raw tomato pulp, on the bioaccessibility of lycopene. Lycopene bioaccessibility was studied by measuring the micellarization during in vitro digestion. Coconut oil, palm oil, cocoa butter, olive oil, sunflower oil and fish oil were selected because of their distinctly different fatty acid composition. Upon adding 5% of lipid to raw tomato pulp, all tested lipids significantly improved the lycopene bioaccessibility. The largest increase in lycopene bioaccessibility was noticed after supplying 5% of sunflower oil, followed by olive oil and cocoa butter (not all differences were significant). A slightly smaller increase was observed when fish oil, coconut oil and palm oil were used. In addition, the effect of different quantities (0–10%) of coconut oil, olive oil and fish oil was examined. Over the entire concentration range, increasing the amount of coconut oil increased the lycopene bioaccessibility, while the highest bioaccessibility was found using 1 and 2% of respectively fish oil and olive oil. Moreover, depending on the amount of added lipid, the type of lipid resulting in the highest lycopene bioaccessibility differed. The results obtained clearly indicate that lycopene bioaccessibility depends both on the type and on the quantity of the lipid present during in vitro digestion of raw tomato pulp.     

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     

Classification of extra virgin olive oils according to their geographical origin using phenolic compound profiles obtained by capillary electrochromatography

A simple and reliable method for the evaluation of the phenolic fraction of extra virgin olive oils (EVOO) by capillary electrochromatography (CEC) with UV–Vis detection, using lauryl acrylate (LA) ester-based monolithic columns, has been developed. The percentages of the porogenic solvents in the polymerization mixture, and the mobile phase composition, were optimized. The optimum monolith was obtained with a monomers/porogens ratio of 40:60% (wt/wt) using a LA/1,3-butanediol diacrylate ratio of 70:30% (wt/wt) and a 1,4-butanediol/1-propanol ratio of 25:75% (wt/wt). A satisfactory resolution between the phenolic compounds was achieved in less than 25 min with a 15:85 (v/v) ACN–water buffer containing 5 mM formic acid at pH 3.0. The method was applied to the analysis of the phenolic fraction of EVOO samples. Using linear discriminant analysis of the CEC phenolic profiles, the EVOO samples belonging to three different geographical origins (Croatia, Italy and Spain) were correctly classified with an excellent resolution among all the categories.     

Self-organizing maps based on chaotic parameters to detect adulterations of extra virgin olive oil with inferior edible oils

A nonlinear algorithm based on chaotic parameters (CPs) has been employed to determine the nature of different output signals obtained from UV–vis spectrophotometer (UV) measurements. These signals come from UV scans of adulterated samples of extra virgin olive oil (EVOO) with refined olive oil or refined olive pomace oil, or from pure samples of EVOO with white random or sinusoidal white random noises. The data collected from this equipment was used to calculate CP values. Then, a self-organizing map was used to detect different types of signals. Using this method, the signals can be identified and classified into five groups depending on their type, the percentage of noise added, and the concentration of adulterant agents, with a misclassification rate of less than 1.3%.     

Enhancing lycopene stability and bioaccessibility in homogenized tomato pulp using emulsion design principles

The objective of this study was to examine the impact of oil, emulsifier, and texture modifier addition on the bioaccessibility of lycopene in homogenized tomato pulp. Different types (olive or corn oil) and levels (0 to 8 wt%) of digestible lipids, a protein-based emulsifier (whey protein isolate, WPI) and/or a polysaccharide-based texture modifier (sodium alginate, SA) were added to the tomato pulp. The addition of these substances increased the amount of lycopene liberated from the tomato tissues. WPI addition led to the formation of smaller oil droplets during homogenization that scattered light more strongly, thereby leading to a tomato pulp that appeared more turbid. SA addition increased the viscosity of the tomato pulp, thereby increasing its uniformity. The best storage stability of lycopene in the tomato pulp was achieved by adding 8% corn oil and 1% WPI. However, the best in vitro bioaccessibility of lycopene (61.5%) was achieved using 6% olive oil and 1% SA. Overall, our results show that lycopene bioaccessibility in tomato products can be increased by careful manipulation of emulsion properties.Industrial relevance: Lycopene is a strongly hydrophobic carotenoid found in tomatoes that contributes to their desirable appearance and potential health benefits. However, it has poor chemical stability and low oral bioavailability, which limits its beneficial effects. We show that the stability and bioaccessibility of lycopene can be improved by high-pressure homogenization of tomato pulp in the presence of specific food additives. This approach may be suitable for the large-scale production of tomato products with enhanced health benefits.     

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.     

基于光谱法的特级初榨橄榄油快速鉴伪技术

本文研究了特级初榨橄榄油中掺入不同比例橄榄果榨油(精炼橄榄油)、菜籽油、玉米油和大豆油的光谱特征,采用荧光光谱和紫外光谱,对掺假样品及纯油样品进行了快速检测。结果表明,特级初榨橄榄油的光谱特征与其他植物油之间差异较大,且掺假体积与吸光度之间存在良好的线性关系(R²>0.89),实现了特级初榨橄榄油的定性鉴别与定量检测,建立了特级初榨橄榄油质量控制体系及其掺假检测分析技术,最低检出限为1%,线性范围为5%～100%(v/v)。系统聚类分析将所有特级初榨橄榄油准确地分为一个亚类,也佐证了此方法的稳定性与可靠性。这种简单快捷的检测技术,有助于特级初榨橄榄油实时、在线橄榄油检测分析技术的研发,为我国橄榄油品质鉴定及产业发展提供有利的技术保障。     

Determination of the oil content in olives by the DSC technique

Differential scanning calorimetry (DSC) has been used to determine the oil content in dried olive pulp of Cassanese and Carolea tree cultivars and to follow their inoliation trends from September to January. DSC was performed by cooling samples of olive dried pulp from -10 to -60vv°C at 1vv°C/min and the amount of oil calculated from the peak area obtained. The enthalpy and temperature range of the crystallization peak for the pure oil were 61 J/g and -34 to -40vv°C for the first cultivar and 54 J/g and -35 to -42vv°C for the second one. The proposed DSC method is fast, specific, and reliable. It does not use solvents, requires smaller samples (<100 mg) than conventional solvent methods, and can detect real absence of water in the sample.     

Aroma biogenesis and distribution between olive pulps and seeds with identification of aroma trends among cultivars

The two constitutive parts of four cultivars (Arbequina, Picual, Local and Manzanilla de Sevilla) grown in Spain were separately analysed in order to establish the role of pulp and seed in the biogenesis of extra virgin olive oil (EVOO) aroma through the lipoxygenase (LOX) pathway. C6 and C5 volatile compounds responsible of EVOO aroma were produced by endogenous enzymes in both parts of olive fruits and the differences can be attributed to different enzymes distribution in pulp and seed. According to results, C6 and C5 volatile compounds have mainly their biogenesis in pulp (80–90%) vs. seed (20–10%), independently of the cultivar considered. A linear discriminant analysis was used to establish discriminant aroma compounds between pulp and seed related to the maturity index. A decrease in trans-2-hexen-1-al and an increase in 1-hexanol with ripeness were observed independently of the cultivar considered. Finally, Partial Least Squares (PLS) regression analysis between pulp and seed aroma compounds allowed to establish those volatile compounds that better describe each cultivar.     

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.     

Evaluation of the quality of olive oil using fatty acid profiles by direct infusion electrospray ionization mass spectrometry

Electrospray ionization mass spectrometry is used to predict the olive oil quality according to European Union marketing standards. Samples were 1:50 diluted in an alkaline 85:15 (v/v) propanol/methanol mixture and directly infused into the electrospray ionization source of an ion trap mass spectrometer. The establishment of ratios of the peak abundances of the free fatty acids followed by linear discriminant analysis was employed to predict the olive oil quality grade. In addition, using multiple linear regression and partial least-squares regression, the percentages of extra virgin and virgin olive oils in binary mixtures were predicted with 5–11% average prediction errors.