Evening primrose oil: a comprehensive review of its bioactives, extraction, analysis, oil quality, therapeutic merits, and safety

Oil crops have become increasingly farmed worldwide because of their numerous functions in foods and health. In particular, oil derived from the seeds of evening primrose (Oenothera biennis) (EPO) comprises essential fatty acids of the omega-6 (ω-6) series. It is well recognized to promote immune cells with a healthy balance and management of female ailments. The nutrients of interest in this oil are linoleic acid (LA, 70-74%) and γ-linolenic acid (GLA, 8-10%), which are polyunsaturated fatty acids (PUFA) that account for EPO's popularity as a dietary supplement. Various other chemicals in EPO function together to supply the body with PUFA, elevate normal ω-6 essential fatty acid levels, and support general health and well-being. The inclusive EPO biochemical analysis further succeeded in identifying several other components, i.e., triterpenes, phenolic acids, tocopherols, and phytosterols of potential health benefits. This comprehensive review capitalizes on EPO, the superior product of O. biennis, highlighting the interrelationship between various methods of cultivation, extraction, holistic chemical composition, sensory characters, and medicinal value. Besides the literature review, this study restates the numerous health advantages of primrose oil and possible drug-EPO interactions since a wide spectrum of drugs are administered concomitantly with EPO. Modern techniques to evaluate EPO chemical composition are addressed with emphasis on the missing gaps and future perspectives to ensure best oil quality and nutraceutical benefits.

Comprehensive adulteration detection of sesame oil based on characteristic markers

Sesame oil has a unique flavor and is very popular in Asian countries, and this leads to frequent adulteration. In this study, comprehensive adulteration detection of sesame oil based on characteristic markers was developed. Initially, sixteen fatty acids, eight phytosterols, and four tocopherols were utilized to construct an adulteration detection model, which screened seven potentially adulterated samples. Subsequently, confirmatory conclusions were drawn based on the characteristic markers. Adulteration with rapeseed oil in 4 samples was confirmed using the characteristic marker of brassicasterol. The adulteration of soybean oil in 1 sample was confirmed using the isoflavone. The adulteration of 2 samples with cottonseed oil was demonstrated by sterculic acid and malvalic acid. The results showed that sesame oil adulteration could be detected by screening positive samples using chemometrics and verifying with characteristic markers. The comprehensive adulteration detection method could provide a system approach for market supervision of edible oils.

Edible Oils Adulteration: A Review on Regulatory Compliance and Its Detection Technologies

Various events of edible oils adulteration with inferior ingredients were reported regularly in recent years. This review is aimed to provide an overview of edible oils adulteration practices, regulatory compliance and detection technologies. Many detection technologies for edible oils adulteration were developed in the past such as methods that are based on chromatography or spectroscopy. Electrochemical sensors like electric nose and tongue are also gaining popularity in the detection of adulterated virgin olive oil and virgin coconut oil. It can be concluded that these detection technologies are essential in the combat with food adulterers and can be improved.

Determination of bovine tallow in butter using a comprehensive method

The detection of animal fats such as tallow in butter using standard criteria is more difficult than vegetable fats. In order to perform a complete assessment, several methods are likely to be used together. In the experimental design of this research, compositional characteristics such as fatty acids, sterols and triacylglycerols, along with the conventional physicochemical characteristics of butter mixed with different percentages of tallow (0–15% w/w) were evaluated. An increase of less than 5% (w/w) in bovine tallow content in butter physicochemical tests, sterols and fatty acids could not indicate the adulteration level but the ratio of C6+8+10+12/C18 fatty acids, C52/C50، C52/C48, C52/C46 triacylglycerols, S1, S3, S5-value equation and C52 triacylglycerols could show this adulteration level in butter. Also, the successive use of fatty acids and triacylglycerols resulted in the capability to determine adulteration in butter including bovine tallow above 1% (w/w).

Raman spectroscopy coupled with chemometric methods for the discrimination of foreign fats and oils in cream and yogurt

The adulteration of milk fat in dairy products with cheaper non-milk based fats or oils is frequently encountered in the dairy industry. In this study, Raman spectroscopy with chemometric was used for the discrimination of foreign fats and oils in milk cream and yogurt. Firstly, binary mixtures of cream and oils (corn and sunflower oil), and vegetable fat blends which are potentially or currently used by the dairy industry were prepared. All fat or oil samples and their binary mixtures were examined by using Raman spectroscopy. Then, fat content of skim milk was adjusted to 3% (w/w) by the milk fat, external oils or fats, and binary mixtures, and was used in yogurt production. The lipid fraction of yogurt was extracted and characterized by Raman spectroscopy. The spectral data were then pre-processed and principal component analysis (PCA) was performed. Raman spectral data showed successful discrimination for about the source of the fats or oils. Temperature effect was also studied at six different temperatures (25, 30, 40, 50, 60 and 70 °C) in order to obtain the best spectral information. Raman spectra collected at higher temperatures were more intense. Obtained results showed that the performance of Raman spectroscopy with PCA was very promising and can be expected to provide a simple and quick way for the discrimination of foreign fats and oils in both milk cream and yogurt. Fermentation and yogurt processing affected clustering of fat samples by PCA, probably depending on some lipolysis or production of new products that can affect the Raman scattering. However, those changes did not affect differentiation of samples by Raman spectroscopy.

Development and optimization of an efficient qPCR system for olive authentication in edible oils

The applicability of qPCR in olive-oil authentication depends on the DNA obtained from the oils and the amplification primers. Therefore, four olive-specific amplification systems based on the trnL gene were designed (A-, B-, C- and D-trnL systems). The qPCR conditions, primer concentration and annealing temperature, were optimized. The systems were tested for efficiency and sensitivity to select the most suitable for olive oil authentication. The selected system (D-trnL) demonstrated specificity toward olive in contrast to other oleaginous species (canola, soybean, sunflower, maize, peanut and coconut) and showed high sensitivity in a broad linear dynamic range (LOD and LOQ: 500ng - 0.0625pg). This qPCR system enabled detection, with high sensitivity and specificity, of olive DNA isolated from oils processed in different ways, establishing it as an efficient method for the authentication of olive oil regardless of its category.

Comparison of different classification methods for analyzing electronic nose data to characterize sesame oils and blends

An electronic nose (e-nose) was used to characterize sesame oils processed by three different methods (hot-pressed, cold-pressed, and refined), as well as blends of the sesame oils and soybean oil. Seven classification and prediction methods, namely PCA, LDA, PLS, KNN, SVM, LASSO and RF, were used to analyze the e-nose data. The classification accuracy and MAUC were employed to evaluate the performance of these methods. The results indicated that sesame oils processed with different methods resulted in different sensor responses, with cold-pressed sesame oil producing the strongest sensor signals, followed by the hot-pressed sesame oil. The blends of pressed sesame oils with refined sesame oil were more difficult to be distinguished than the blends of pressed sesame oils and refined soybean oil. LDA, KNN, and SVM outperformed the other classification methods in distinguishing sesame oil blends. KNN, LASSO, PLS, and SVM (with linear kernel), and RF models could adequately predict the adulteration level (% of added soybean oil) in the sesame oil blends. Among the prediction models, KNN with k = 1 and 2 yielded the best prediction results.

Detection of Butter Adulteration with Lard by Employing (1)H-NMR Spectroscopy and Multivariate Data Analysis

The authentication of food products from the presence of non-allowed components for certain religion like lard is very important. In this study, we used proton Nuclear Magnetic Resonance ((1)H-NMR) spectroscopy for the analysis of butter adulterated with lard by simultaneously quantification of all proton bearing compounds, and consequently all relevant sample classes. Since the spectra obtained were too complex to be analyzed visually by the naked eyes, the classification of spectra was carried out.The multivariate calibration of partial least square (PLS) regression was used for modelling the relationship between actual value of lard and predicted value. The model yielded a highest regression coefficient (R(2)) of 0.998 and the lowest root mean square error calibration (RMSEC) of 0.0091% and root mean square error prediction (RMSEP) of 0.0090, respectively. Cross validation testing evaluates the predictive power of the model. PLS model was shown as good models as the intercept of R(2)Y and Q(2)Y were 0.0853 and -0.309, respectively.

Cultivar origin and admixture detection in Turkish olive oils by SNP-based CAPS assays

The aim of this study was to establish a DNA-based identification key to ascertain the cultivar origin of Turkish monovarietal olive oils. To reach this aim, we sequenced short fragments from five olive genes for SNP (single nucleotide polymorphism) identification and developed CAPS (cleaved amplified polymorphic DNA) assays for SNPs that alter restriction enzyme recognition motifs. When applied on the oils of 17 olive cultivars, a maximum of five CAPS assays were necessary to discriminate the varietal origin of the samples. We also tested the efficiency and limit of our approach for detecting olive oil admixtures. As a result of the analysis, we were able to detect admixing down to a limit of 20%. The SNP-based CAPS assays developed in this work can be used for testing and verification of the authenticity of Turkish monovarietal olive oils, for olive tree certification, and in germplasm characterization and preservation studies.

Authentication of dried distilled grain with solubles (DDGS) by fatty acid and volatile profiling

Demand for ethanol substituted fuels from the utilisation of cereal based biofuel has resulted in an over production of dried distillers grains with solubles (DDGS) that are now readily available on the animal feed market. With this rapid emerging availability comes potential variability in the nutritional value of DDGS and possible risks of feed contaminants. Subsequently, the authentication and traceability of alternative animal feed sources is of high priority. In this study and as part of the EU research project “Quality and Safety of Feeds and Food for Europe (QSAFFE FP7-KBBE-2010-4) an attempt was made to classify the geographical origin of cereal grains used in the production of DDGS material. DDGS material of wheat and corn origin were obtained from Europe, China, and the USA. Fatty acid profiles and volatile fingerprints were assessed by gas chromatography flame ionisation (GC-FID) and rapid proton transfer reaction mass spectrometry (PTR-MS) respectively. Chemometric analysis of fatty acid profiles and volatile fingerprints allowed for promising classifications of cereals used in DDGS material by geographical and botanical origin and enabled visual representation of the data. This objective analytical approach could be adapted for routine verification of cereal grains used in the production of DDGS material.

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Fatty acid and volatile composition of dried distillers grains were analysed.

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Fatty acid and volatile fingerprints of samples were studied by chemometric models.

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Models showed good classifications for botanical, geographical origin and process.

Use of FTIR for rapid authentication and detection of adulteration of food

Fourier transform infrared (FTIR) spectroscopy is an appealing technology for the food industry because simple, rapid, and nondestructive measurements of chemical and physical components can be obtained. Advances in FTIR instrumentation combined with the development of powerful multivariate data analysis methods make this technology ideal for large volume, rapid screening and characterization of minor food components down to parts per billion (ppb) levels. Because of the use of FTIR techniques in quality and process control applications, the food industry is already familiar with the technology and its potential to expand to monitoring for food adulteration. The aim of this review is to compile the current research on applications of near infrared (NIR) and mid-infrared (MIR) spectroscopy for rapid authentication and detection of adulteration in food.

Nutritional, fatty acid and triacylglycerol profiles of Castanea sativa Mill. cultivars: a compositional and chemometric approach

Four Portuguese chestnut cultivars from the "Castanha da Terra Fria" protected designation of origin were selected: Aveleira, Boa Ventura, Judia and Longal. The nutritional parameters (moisture, fat, protein, carbohydrates, ash and energy) as well as fibers (neutral detergent fiber, acid detergent fiber, acid detergent lignin and cellulose) were characterized. Moisture was the major component followed by carbohydrates, protein and fat, resulting in an energetic value lower than 195 kcal/100 g of fresh fruit. In order to find significant differences among cultivars, the lipidic fraction was studied in detail. Fatty acids (FA) were determined by gas-liquid chromatography with flame ionization detection, revealing a clear prevalence of C18:1 and C18:2, two FA very well-known due to their beneficial effects on human health, e.g., in the prevention of cardiovascular diseases. A triacylglycerols (TAG) profile was obtained by reversed-phase high-performance liquid chromatography with evaporative light-scattering detection. TAG analysis is very important because it furnishes highly specific information due to genetic control of the stereospecific distribution of FA on the glycerol molecule. OLL, PLL, OOL and POL were the major compounds. As far as we know this is the first complete characterization of TAG in chestnut. The obtained data were screened through an analysis of variance (to evaluate the accuracy of the method as well as the uniformity of results for each cultivar) and a discriminant analysis (DA), which gave good results, once that, in some cases, the four cultivars were clustered in four individual groups, obtained through the definition of two DA dimensions.

Pomegranate oil analysis with emphasis on MALDI-TOF/MS triacylglycerol fingerprinting

Pomegranate oil (PGO) is a unique and quite rare edible oil produced from Punica granatum L. seeds. It is considered to be a powerful health-benefiting agent, due to its antioxidative, anticancer, and antilipidemic properties. The aim of this study was to achieve a comprehensive and detailed profile of the different components of PGO. The fatty acid profile and phytosterol composition were determined by GC-MS; the triacylglycerol (TAG) compositions were profiled by the mass spectrometry tool of MALDI-TOF/MS. Results showed linolenic acid (18:3) to be the predominant fatty acid in the PGO (64-83%), as previously reported. The linolenic acid fraction was composed of four different chromatographically separated peaks that are assumed, according to MS data (based on both FAME and DMOX derivatization), to be attributed to different geometric isomers of conjugated linolenic acid (CLNA), punicic acid (18:3: 9-cis,11-trans,13-cis) being the major isomer. The MALDI-TOF/MS finger printing results showed the different TAG compositions present in the PGO, the major ones being LnLnLn and LnLnP. This unique PGO TAG fingerprint enables it to be differentiated from most other common edible oils. Phytosterols were found in quite a high concentration in the PGO (4089-6205 mg/kg), about 3-4-fold higher than in soybean oil. A detailed profile of the phytosterols in the PGO showed a wide variety, the major phytosterols being beta-sitosterol, campesterol, and stigmasterol. This study depicts a new detailed analysis of PGO, showing great potential for further research regarding the physiological effects of specific valuable components in pomegranate oil.

The use of multivariate modelling of near infra-red spectra to predict the butter fat content of spreads

In order to obtain a rapid method that can detect adulteration of butter fats with cheaper vegetable fats, the use of NIR spectroscopy and multivariate modelling was explored. For model building and validation, an extensive set of samples was collected, consisting of 152 butter samples, 42 oils and 200 blends thereof. Variations in butter fat composition are reflected in distinct NIR spectral regions. Principal components analysis and partial least square discriminant analysis was used to inspect the variation within the sample set. As reference values for training partial least squares models, butter fat levels as declared by suppliers were taken, as well as C4:0 fatty acid levels as measured directly by GC. All samples were used for training, except for 100 blends, which were used later for validation. Different pre-processing and PLS approaches were explored, resulting in models that had a RMSEPs for butter fat and C4:0 fatty acid level in the range of 4.3-8.2 and 0.33-0.38% (w/w), respectively. The performance of NIR in assessment of C4:0 fatty acid levels is lower as for GC, but this disadvantage is outweighed by shorter measurement times and the lower skill levels required. Furthermore NIR is able to assess overall levels of butter fat, in addition to the indirect indicator provided by the C4:0 fatty acid level.

Implementation of Physicochemical and Sensory Analysis in Conjunction with Multivariate analysis towards Assessing Olive Oil Authentication/Adulteration

The authenticity of products labeled as olive oils, and in particular as virgin olive oils, stands for a very important issue both in terms of its health and commercial aspects. In view of the continuously increasing interest in virgin olive oil therapeutic properties, the traditional methods of characterization and physical and sensory analysis were further enriched with more advanced and sophisticated methods such as HPLC-MS, HPLC-GC/C/IRMS, RPLC-GC, DEPT, and CSIA among others. The results of both traditional and "novel" methods were treated both by means of classical multivariate analysis (cluster, principal component, correspondence, canonical, and discriminant) and artificial intelligence methods showing that nowadays the adulteration of virgin olive oil with seed oil is detectable at very low percentages, sometimes even at less than 1%. Furthermore, the detection of geographical origin of olive oil is equally feasible and much more accurate in countries like Italy and Spain where databases of physical/chemical properties exist. However, this geographical origin classification can also be accomplished in the absence of such databases provided that an adequate number of oil samples are used and the parameters studied have "discriminating power."

Reducing fragmentation observed in the matrix-assisted laser desorption/ionization time-of-flight mass spectrometric analysis of triacylglycerols in vegetable oils

Edible oils consist primarily of triacylglycerols (TAGs). Matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectra of the oils are typically dominated by sodium adducts of these TAGs but also show prominent fragment ions (that do not contain sodium), which can interfere with analytical measurements of other components in oils. The fragments seemingly correspond to the loss of a fatty acid moiety from the sodiated TAGs as a sodium salt: RCOONa. However, a previous study suggested that the fragments actually arise from nearly complete fragmentation of unseen protonated TAGs. These authors suggested that the fragmentation occurs so rapidly and completely that protonated TAGs are not normally observed in the spectra of these oils. In this paper, we present evidence to support their theory and also demonstrate an approach to eliminate these interfering ions from the MALDI-TOF mass spectra via addition of a base to the matrix/sample mixture. The added base does not impede formation of the sodiated TAGs, but does significantly reduce the amount of fragments observed. We propose that this occurs by depleting the H+ ions from the matrix, thus preventing the formation of significant numbers of protonated TAGs in the first place. For measurements by MALDI-TOF, the relative abundances of the fragment ions are related to the strength of the base, and can be almost completely eliminated. However, in longer time-scale experiments such as in post-source decay and Fourier transform mass spectrometry, sodiated and non-sodiated diacylglycerol (DAG)-like fragments are present in spectra, regardless of whether or not a base is added to the sample.

Influence of Cultivar and Environmental Conditions on the Triacylglycerol Profile of Hazelnut (Corylus avellana L.)

The oil of several hazelnut (Corylus avellana L.) samples was extracted and evaluated for their triacylglycerol (TAG) composition. Trials were conducted in two Portuguese localities (Vila Real and Felgueiras) during three consecutive years and involved a total of 19 cultivars. The samples were analyzed by reversed-phase high-performance liquid chromatography with evaporative light-scattering detection. Sample preparation was fast and simple, consisting only of the dissolution of the oil in acetone, homogenization, and filtration, allowing this technique to be suitable for routine analyses. All samples presented a similar qualitative profile composed of eleven compounds: LLL, OLL, PLL, OOL, POL, PPL, OOO, POO, PPO, SOO and PSO (P, palmitoyl; S, stearoyl; O, oleoyl; and L, linoleoyl). The main components were OOO, LOO, and POO, reflecting the high content of oleic acid in hazelnut oils. A total of 79 different samples were studied, and the obtained data were statistically analyzed. Significant differences were verified in canonical variate plots when cultivars were grouped by country of origin. In general, the American cultivars were richer in TAGs with saturated fatty acids moieties, and the group of French, German, and English cultivars was richer in TAGs containing linoleic acid moieties. Differences were also significant when cultivars were grouped by year of production, showing that besides genetic factors, the TAG composition can be influenced by environmental factors.

Authenticity Assessment of Dairy Products

The authenticity of dairy products has become a focal point, attracting the attention of scientists, producers, consumers, and policymakers. Among many others, some of the practices not allowed in milk and milk products are the substitution of part of the fat or proteins, admixtures of milk of different species, additions of low-cost dairy products (mainly whey derivatives), or mislabeling of products protected by denomination of origin. A range of analytical methods to detect frauds have been developed, modified, and continually reassessed to be one step ahead of manufacturers who pursue these illegal activities. Traditional procedures to assess the authenticity of dairy products include chromatographic, electrophoretic, and immunoenzymatic methods. New approaches such as capillary electrophoresis, polymerase chain reaction, and isotope ratio mass spectrometry have also emerged alongside the latest developments in the former procedures. This work intends to provide an updated and extensive overview since 1991 on the principal applications of all these techniques together with their advantages and disadvantages for detecting the authenticity of dairy products. The scope and limits of different tools are also discussed.

Triacylglycerol composition of walnut (Juglans regia L.) cultivars: characterization by HPLC-ELSD and chemometrics

A total of 26 walnut (Juglans regia L.) samples from 9 cultivars (Arco, Franquette, Hartley, Lara, Marbot, Mayette, Mellanaise, Parisienne, and Rego) harvested in the 2001, 2002, and 2003 crop years and grown in two geographical origins (Braganca and Coimbra, Portugal) were evaluated with regard to their triacylglycerol composition. The methodology employed was reversed-phase high-performance liquid chromatography coupled to an evaporative light-scattering detector (RP-HPLC-ELSD) after extraction of the lipidic fraction of the nuts. Nine compounds were separated, identified, and quantified. All samples presented an identical qualitative profile composed by LLnLn, LLLn, LLL, OLLn, OLL, PLL, OOL, and PLO (P = palmitoyl; O = oleoyl; L = linoleoyl; Ln = linonenoyl). Trilinolein (LLL) was the major triglyceride, followed by dilinoeoyl-oleoyl-glycerol (OLL) and dilinoleoyl-linolenoyl-glycerol (LLLn), with mean values of 37.7, 18.5, and 18.4%, respectively. Significant differences in composition were found between cultivars, and these differences were also significant when cultivars were grouped by year of production, showing that besides genetic factors, the triacylglycerol composition can be strongly influenced by environmental factors.