Quality Of Edible Oils Research Articles

Excitation-emission fluorescence spectroscopy and sparse chemometric methods for grape seed oil classification and authentication

Grape seed oil (GSO) authentication and classification have recently become the most important aspects of edible oil quality control due to its high nutritional values. In the present contribution, excitation-emission fluorescence spectroscopy and sparse chemometric methods were used for the classification of GSO obtained from different Iranian grape genotypes and the detection of GSO adulteration with refined sunflower oil (SFO). The fluorescence spectra were collected in the wavelength ranges of λex = 200–500 nm and λem = 200–800 nm. To develop multivariate models, more than 200 samples from five different varieties of GSO were used. The sparse version of N-way partial least squares discriminant analysis (sNPLS-DA) was utilized to build an interpretable classification model. Classification accuracies for the sNPLS-DA model were 1.00 for predicting all grape genotypes. The collected fluorescence data revealed a distinct intensity difference between the Chafteh GSO and other GSOs in λex = 270–310 nm, and λem = 300–350 nm. To simulate the adulteration of GSO with SFO, 35 binary blends of Chafteh GSO samples (as a higher-quality oil) were prepared at adulterant levels from 10% to 50%. Sparse multivariate regression techniques, including the least absolute shrinkage and selection operator (Lasso), Ridge, and Elastic net were applied for quantitative analysis of GSO adulteration. The coefficient of multiple determination (R2) and the RMSE for the Lasso model were 0.914 and 0.013, respectively, for the external test sets. The results showed that the sparse chemometric methods coupled with excitation-emission fluorescence spectroscopy can be used as interpretable and reliable tools for quality control and adulteration detection of oil samples in the food industry and commerce.

Evaluation of physicochemical parameters of edible oils at room temperature and after heating at high temperature

Edible oils and fats are recognized as vital constituents of our daily diet and contribute significantly to the regulation of different body functions. Edible oil quality is largely determined by physicochemical characteristics and sensory evaluation due to its nature and processing procedure. The present study includes evaluation of different physicochemical parameters of soybean, palm, mustard and bran oil at room temperature and after heating at 180oC for 10 mins using different analytical methodologies. These properties were studied to evaluate the compositional quality of oils and also to investigate the effect of heating as it ultimately changes the physicochemical and sensory properties of the oil. Results revealed that there was a significant difference in physicochemical parameters among four types of oils before and after heating. Peroxide, free fatty acid and acid value were increased with the increase of temperature at 180oC. The iodine value was highest in soybean oil (133.17 mg/g), followed by mustard oil (110.59 mg/g) but was lowest in palm oil (46.18 mg/g). In addition, saponification value was found to be 187.1, 202.39, 191.38 and 181.6 mg/g in soybean, palm, mustard and bran oil, respectively. The study also indicated that the L*, a* and b* values of oil decreased significantly with heating temperature. However, sensory evaluation results also found that soybean oil and bran oil were more preferable to cooking than the other two oils. Taking consideration of all parameters the study concluded that soybean oil and bran oil had the superior quality to other samples.

Incorporation of natural antioxidants extracted from strawberry, cinnamon, beetroot, and ginger; into virgin coconut oil for expansion of its shelf life

Lipid oxidation significantly deteriorates the quality of edible oils and further leads to changes in flavour, storage properties, and overall nutritional value. Phenolic phytochemicals of strawberry (S), beetroot (B), cinnamon (C), and ginger (G) were extracted into ethanol using the reflux method and evaluated for their total polyphenol content (TPC), total flavonoid content (TFC), and antioxidant potential. These phytochemicals were then incorporated into virgin coconut oil (VCO) as individual antioxidants and combinations, to expand its shelf life and mitigate the negative effects of oxidation. The antioxidant fortified VCO subjected to accelerated oxidation was assessed under the parameters of peroxide value (PV), free fatty acid value (FFA), conjugated dienes (CD), conjugated trienes (CT), and Thiobarbituric acid related substances assay (TBARS) value with comparison to control (VCO), gallic acid, Vitamin E, and BHT. The TPC of strawberry, cinnamon, beetroot, and ginger were 198.00 ± 1.41, 135.00 ± 1.41, 55.00 ± 1.41, and 151.51 ± 0.071 mg GAE/g respectively and their antioxidant potential ranged in the order of S> B> C> G based on their IC50 DPPH value. The PV of (VCO, and VCOGC), VCOSG, VCOSCBG, and VCOBHT have reached the rancid PV of 30–40 meq/Kg range in 12, 24, 48, and 72 h respectively. The FFA of control, VCOVit.E, and VCOBHT was higher than that of VCOGC, VCOSG, and VCOSGBC, after 72 h. The CD and CT values increased with time, similar to PV with storage time. Nevertheless, the combinations SB (1:1) and SGBC (1:1:1:1) at 1500 ppm could be used as natural antioxidant and might be explored to prevent the oxidation of vegetable oils. Therefore, the combination could be used as preservative ingredients in the oil-based food industries.

Weighted Moth-Flame Optimization Algorithm for Edible Oil Quality Detection Using Microwave Technologies

Weighted Moth-Flame Optimization Algorithm for Edible Oil Quality Detection Using Microwave Technologies

Spray assisted preconcentration method combined with HPLC – Continuous flow hydride generation – FAAS for inorganic arsenic speciation in olive oil samples

Speciation analysis of arsenic in edible oils is an important topic in terms of the assessment of its risks for human health and the quality of edible oils. In this study, high performance liquid chromatography – continuous flow hydride generation – flame atomic absorption spectrometry (HPLC-CFHG-FAAS) system after vortex assisted reverse phase spray-based fine droplet formation liquid phase microextraction (VA-RP-SFDF-LPME) method was proposed to qualify/quantify arsenite and total arsenic. Limit of detection (LOD) and limit of quantification (LOQ) for arsenite were calculated as 2.86 µg kg–1 (as As) and 9.52 µg kg–1 (as As), respectively. After the extraction/preconcentration process, a prereduction was carried out in the presence of 0.010 mol/L HCl (containing 0.39% L-cysteine) with heat (90 ± 5 oC) for the determination of total arsenic content while arsenite was directly determined via the developed system. Recovery for arsenite and total inorganic arsenic were in the range of 91.5 – 120.4% and 90.0 – 104.4%, respectively. The developed method is proposed for the analysis of olive oil samples containing inorganic arsenic species. This is the first study to carry out the inorganic arsenic speciation in olive oil by HPLC-CFHG-FAAS system after the preconcentration of the species by the VA-RP-SFDF-LPME system. For the matrix including arsenite and arsenate, the developed method can be safely used to find the concentration of both species accurately.

A stable quantitative trait locus on chromosome A10 improves the oil content of a backbone parent in Brassica napus L.

One of the most important breeding goals for rapeseed (Brassica napus L.) is improving the oil content (OC) to increase edible or industrial oil quality. Using backbone parents as research materials to excavate OC genetic loci is not only helpful in enhancing the understanding of the genetic basis of OC in rapeseed but also offers a promising approach to improve backbone parents. In this study, a doubled haploid population constructed using the backbone parent 19514 A (with low OC) and the inbred line ZY50 (with high OC) were investigated in eight environments. A total of 30 quantitative trait loci (QTLs) were identified, among which qOC.A10 was detected in six environments. Local QTL scanning for the BC4F2 population showed that qOC.A10 accounted for 22.77% of the phenotypic variance and 0.97% of the additive effect. Further, we improved the parent 19514 A on qOC.A10 by marker-assisted selection, and the background response rate of the improved line A10–19514A reached 97.5%. The phenotypic identification results showed that the OC of A10–19514A and its hybrid significantly increased compared with that of the control, with no negative effects on other agronomic traits. Transcriptome analysis and sequence difference analysis facilitated the prediction of potential functional genes of qOC.A10. This study increases the knowledge regarding the genetic foundation of OC in rapeseed. Furthermore, it identified and confirmed a stable QTL that can be detected in various studies and possesses practical breeding significance.

Comparison on the Physicochemical Parameters of Five Commercially Available Branded Oils in Tansen Bazar

Oils are unsaturated triglycerides or lipids which are liquid at room temperature. The physicochemical parameters of oils should be analyzed to assess the quality and functionality of the oil. The parameters like saponification value, acid value, iodine value, and insoluble impurities can identify characteristics of edible vegetable oils available in Nepali market whose characteristics remain indistinct and for this, the quality of individual edible oil also remains unknown. Objective of this research work is to get idea about other applicability of vegetable oils instead of commonly used mustard oils. Five different branded and certified samples of oils: coconut oil, olive oil, castor oil, soybean oil and sunflower oil were collected from different shops of Tansen bazaar for quality analysis. The saponification values, acid values, iodine values and percentage insoluble impurities of the selected oil samples were recorded in the range (178.54-284.70) mg KOH/gm, (0.48-4.48) mg KOH/gm, (8.75-141.2) mg KOH/gm and (0.004-0.078) % respectively. This study showed that all the selected five samples of oils are very good for soap making process or studied coconut oil was observed to produce the best quality soap. Analyzed olive oil was not consumable or good as skin care product either. This study had recommended public not to use pre-heated oil more than one time and also, analyzed sunflower oil had been recommended as the best suitable for all purposes among all samples of oils under study from Tansen.

Engineering of polarity-responsive fluorescent probe for real-time measurement and visualization of total polar materials in edible oils

The content of total polar materials (TPM) in edible oils is generally accepted as a reliable indicator of the quality of edible oils. A high TPM value may signify that the flavor has been compromised and its consumption may lead to adverse effects on human health. However, the lack of convenient and user-friendly detection methods for the detection of TPM remains a challenge. To address this, a sensitive polarity-responsive fluorescent probe has been designed. A good linear relationship was observed for the ratio of the intensity of green to red fluorescence signal (I504 nm/I625 nm) and the TPM content over the range 1.1–29.3% for soybean oil and 0.1–27.5% for salad oil, respectively. A portable fluorescence sensor system was constructed, which provided a stable platform for the convenient detection of TPM via naked eye observation. These results indicate that the probe has great potential for TPM detection of edible oils in the food safety industry.

Photoacoustic Spectroscopy Combined with Integrated Learning to Identify Soybean Oil with Different Frying Durations.

Soybean oil produces harmful substances after long durations of frying. A rapid and nondestructive identification approach for soybean oil was proposed based on photoacoustic spectroscopy and stacking integrated learning. Firstly, a self-designed photoacoustic spectrometer was built for spectral data collection of soybean oil with various frying times. At the same time, the actual free fatty acid content and acid value in soybean oil were measured by the traditional titration experiment, which were the basis for soybean oil quality detection. Next, to eliminate the influence of noise, the spectrum from 1150 cm-1 to 3450 cm-1 was selected to remove noise by ensemble empirical mode decomposition. Then three dimensionality reduction methods of principal component analysis, successive projection algorithm, and competitive adaptive reweighting algorithm were used to reduce the dimension of spectral information to extract the characteristic wavelength. Finally, an integrated model with three weak classifications was used for soybean oil detection by stacking integrated learning. The results showed that three obvious absorption peaks existed at 1747 cm-1, 2858 cm-1, and 2927 cm-1 for soluble sugars and unsaturated oils, and the model based on stacking integrated learning could improve the classification accuracy from 0.9499 to 0.9846. The results prove that photoacoustic spectroscopy has a good detection ability for edible oil quality detection.

Identification of sunflower, rapeseed, flaxseed and sesame seed oil metabolomic markers as a potential tool for oil authentication and detecting adulterations.

Testing the composition, quality and authenticity of edible oils is crucial to safeguard the consumers' rights and health. The aim of our study was to identify oil-specific markers to enable the differentiation and authentication of sunflower, sesame, flaxseed and rapeseed oils, and to evaluate their antioxidant activity, total phenolic and carotenoid content. A metabolomic approach based on liquid chromatography coupled to quadrupole-time-of-flight mass spectrometry was employed for marker discovery. Spectrophotometric method was used for determination of antioxidant activity, total phenolic and carotenoid content. 76 oil samples from the four different manufacturers were examined. We identified 13 oil-specific markers for sunflower seed oil, 8 for rapeseed oil, 5 for sesame seed oil and 3 for flaxseed oil, their retention times, accurate masses, and characteristic fragment ions are reported. The abundances of the markers for each plant species were found to vary depending on the oil producer and the product batch. Significant differences in antioxidant activity, total phenolic and carotenoid content were also observed both between oils and within oil type. The highest total phenolic content (84.03 ± 4.19 to 103.79 ± 3.67 mg of gallic acid/kg) and antioxidant activity (245.67 ± 7.59 to 297.22 ± 2.32 mg Trolox/kg) were found in sesame seed and flaxseed oils, respectively. Identified metabolic markers can be used as qualitative markers to confirm the authenticity or to detect adulterations of oils. Composition, properties and authenticity testing should be more rigorous for food products marketed as health-promoting.

Determinación de la estabilidad del aceite de semilla de Moringa oleifera bajo condiciones de freído prolongadas

Moringa oleifera is a crop that has spread throughout the tropics worldwide and its seeds are a non-conventional source of edible oil. The objective of this study was to evaluate the oxidative stability and fatty acid profile of M. oleifera oil under frying conditions for an extended time. Typical parameters used to characterize and assess the quality of edible oils were evaluated following standard methods such as the acid and saponification value. In addition, oxidative stability was monitored by measuring conjugated dienes and thiobarbituric acid reactive substances (TBARS) for primary and secondary oxidation, respectively. The fatty acid profile was determined by gas-liquid chromatography. The results showed 1-2% and 170-340 mg NaOH/g, for the acid and saponification indexes, respectively. In addition, the oxidation values for conjugated dienes were below 10 and less than 10 μmol of malondialdehyde equivalents per g for TBARS. On the other hand, eight primary fatty acids were identified. Generally, the fatty acid profile was not affected during the evaluated frying conditions. Finally, the results show that M. oleifera oil has significant stability to oxidation and hydrolysis under prolonged thermal conditions.

Rapid Non-Invasive Capacitive Assessment of Extra Virgin Olive Oil Authenticity

Economically motivated adulteration (EMA) and/or cross-contamination are the two major factors resulting in the substandard quality of premium edible oil like extra virgin olive oil (EVOO) produced in food and beverage (F&B) fast-moving consumer goods (FMCG) industries. Current quality assurance methods (e.g., spectroscopy and chromatography) in FMCG involve intrusive sample extraction and ex situ analysis in a laboratory using expensive bulky instrumentation, which is neither integrable inline nor scalable to match the production throughput. Such techniques do not meet the industrial requirements of in situ testing, non-intrusive analysis, and high throughput inspection (100% product verification) leading to food loss and package waste from unwanted batch rejects. Herein, a low-cost electrical approach based on capacitance is proposed to show the proof of concept for screening EVOO-filled containers non-invasively for adulteration without any sample extraction by capturing the differences in the dielectric properties of mixed oils. The sensor system displayed a fast response (100 ms) and low detection limits for different adulterants (olive oil (32.8%), canola oil (19.4%), soy oil (10.3%) and castor oil (1.7%)), which is suitable for high-throughput (>60 sample/min) screening. Furthermore, a low-cost automated system prototype was realized to showcase the possibility of translating the proof of concept for possible scaling up and inline integration.

Analog interface based on capacitance multiplier for capacitive sensors and application to evaluate the quality of oils

<abstract><p>Currently, interdigital capacitive (IDC) sensors are widely used in science, industry and technology. To measure the changes in capacitance in these sensors, many methods such as differentiation, phase delay between two signals, capacitor charging/discharging, oscillators and switching circuits have been proposed. These techniques often use high frequencies and high complexity to measure small capacitance changes of fF or aF with high sensitivity. An analog interface based on a capacitance multiplier for capacitive sensors is presented. This study includes analysis of the interface error factors, such as the error due to the components of the capacitance multiplier, parasitic capacitances, transient effects and non-ideal parameters of OpAmp. A design approach based on an IDC sensor to measure the quality of edible oils is presented and implemented. The quality relates to the total polar compounds (TPC) and consequently to relative electrical permittivity <inline-formula><tex-math id="M1">\begin{document}$ {\varepsilon }_{r} $\end{document}</tex-math></inline-formula> of the oils. A measurement system has been implemented to measure the capacitance of the IDC sensor, which depended on <inline-formula><tex-math id="M2">\begin{document}$ {\varepsilon }_{r} $\end{document}</tex-math></inline-formula>. The simulation and experimental results showed that, for a capacitance multiplication factor equal to 1000, changes of 3.3 µs/100 fF can be achieved with an acceptable level of noise, which can be easily measured by a microcontroller.</p></abstract>

Quality control of woody edible oil: The application of fluorescence spectroscopy and the influencing factors of fluorescence

Woody edible oil plays an increasingly important role in people's lives to become one of the most popular and expensive edible oil in the market to because of its high quality and healthful properties. It's more susceptible to adulteration with other cheaper oil by theses unscrupulous traders for high profits. Therefore, a rapid, intuition, and non-destructive techniques for woody edible oil authentication should be developed. The current traditional determination methods are tedious and destructive to detect woody edible oil. Fluorescence spectroscopy possesses the advantages of rapid, green, multi-mode, and low-cost analysis as soon as a non-destructive method can be used to analyze the quality of woody edible oil in agricultural sciences. It can be used to detect authentication of woody edible oil by combining fluorescence spectroscopy and chemometrics. However, to the best of our knowledge, a comprehensive review on fluorescence spectroscopy for the quality of woody edible oil remains to be published. In this review, the fluorescence influencing factors of woody edible oil, included the cultivars, extraction technologies and geographical origin have been emphasized and highlighted the applications of fluorescence spectroscopy in quality control and geographical origin traceability of woody edible oil. In addition, the application of fluorescence-transmittance imaging technology in woody edible oil has been addressed. In the future, fluorescence spectroscopy could be applied in the rapid detection and online detection of hazardous substances in woody edible oil by developing portable devices.

Effect of refinement and production technology on the molecular composition of edible cottonseed oils from a large industrial scale production

• Foodomics methodology based on GC–MS and 1 H NMR was demonstrated to uncover molecular profiles of cottonseed oils. • Effects of oil refinement stages and technologies on molecular profiles are discovered. • Oil refinement leads to reduced undesirable fatty acids, diglycerides, and steroids. • An increased concentrations of hydrocarbons and aldehydes is associated with oil refinement. Unrefined, refined and refined-deodorized cottonseed oils from pressing or extraction technologies were screened using proton (1H) nuclear magnetic resonance (NMR) spectroscopy and gas chromatography-mass spectrometry (GC-MS). GC–MS of derivarized and non-derivatized (intact oil) cottonseed oils allowed detection of nearly 100 compounds. These included fatty acids (FA), linoleic (relative percentage concentration of 51–58%), palmitic (21–24%), oleic (18–23%) and stearic acids (1.8–2.2%) in hydrolysed oils, and β-sitosterol (31–43%), linoleic acid (7–29%), γ- and α-tocopherol (11–22%), and squalene (2–4%) in intact oils. NMR spectra of intact oils contained 91 resonances and were dominated by methylene (40.7–41.4%), methyl (14.1–14.2%), and methine (6.7–6.8%) protons of FA and triglycerides. Analysis of the molecular profiles revealed a dominating effect of the processing followed by the production technology. Oil refinement reduced undesirable free FA, diglycerides and gossypol, but increased hydrocarbons and aldehydes. The refined press oil contained higher levels of steroids and less free FA compared to refined extract oil. Thus, the study showed the potential of foodomics to evaluate the in-depth molecular quality of edible oils.

Low-cost liquid lipase selective deacidification of corn oil with high triglyceride yield

In order to remove free fatty acids (FFA) in crude oil and improve edible oil quality, deacidification was often used in oil refining. In this work, several liquid enzymes were firstly screened for the selective deacidification of the degummed corn oil, and ethanol was used as a novel fatty acyl acceptor in solvent-free system, which showed a good selective deacidification efficiency and high triglyceride yield. Reaction conditions were optimized by response surface methodology as follows: 3 % enzyme dosage and 20:1 substrate ratio (alcohol/FFA) at 50 °C for 50 min. Under these conditions, the acid value, yield of neutral oil, and contents of sterol and vitamin E of corn oil were 0.31 ± 0.06 mgKOH/g, 94.0 ± 0.5 %, 1,012.9 ± 11.2 mg/100 g, and 1,320.0 ± 3.8 mg/kg, respectively. Meanwhile, thermodynamic and kinetic parameters were investigated. These results showed that this process was beneficial to selective deacidification, high yields of neutral oil and bioactive components in corn oil.

1H LF-NMR Self-Diffusion Measurements for Rapid Monitoring of an Edible Oil's Food Quality with Respect to Its Oxidation Status.

The food quality of edible oils is dependent on basic chemical and structural changes that can occur by oxidation during preparation and storage. A rapid and efficient analytical method of the different steps of oil oxidation is described using a time-domain nuclear magnetic resonance (TD-NMR) sensor for measuring signals related to the chemical and physical properties of the oil. The degree of thermal oxidation of edible oils at 80 °C was measured by the conventional methodologies of peroxide and aldehyde analysis. Intact non-modified samples of the same oils were more rapidly analyzed for oxidation using a TD-NMR sensor for 2D T1-T2 and self-diffusion (D) measurements. A good linear correlation between the D values and the conventional chemical analysis was achieved, with the highest correlation of R2 = 0.8536 for the D vs. the aldehyde concentrations during the thermal oxidation of poly-unsaturated linseed oils, the oil most susceptible to oxidation. A good correlation between the D and aldehyde levels was also achieved for all the other oils. The possibility to simplify and minimize the time of oxidative analysis using the TD NMR sensors D values is discussed as an indicator of the oil’s oxidation quality, as a rapid and accurate methodology for the oil industry.

Confirmatory assessments of putative quality and nutritional properties of branded and unbranded commercial edible oils

Dietary associated non-communicable diseases have become a major concern and consumption of branded and unbranded vegetables oils may be one out of many probable contributing factors. Thus, the objective of this preliminary study was to access the nutritional qualities and trans-fat contents of 28 randomly selected three commonly consumed vegetable oils (crude palm oil CPO, soybean oil SBO, and peanut oil PNO) from cross-sectional area of the country. CPOs samples exhibited an upper limit of 5.18% for acidity, which is slightly outside minimum standard requirement for crude oil (<5.00%). Similarly, both SBOs and PNOs were above tolerant limit for acidity (>0.30%). Six of the nine CPOs had peroxide value > 8.0 meqO2/kg, while none of the refined oils was <1.63 meqO2/kg – an indication of oxidative instability. Although, moisture content, conjugated trienes and dienes were significantly higher in CPOs, but the oils exhibited lower trans-fat content with a range 0 – 6.27% compared to SBOs (3.73 – 9.72%) and PNOs (0.72 – 7.14%). CPOs were higher in total phenol (TPC), tocopherol (TFR), and carotenoid (CAR) contents, that could make up for the low oxidative stability indices. Among the variables predicting trans-fat contents of the oils using variable important projection (VIP) model, saturated, polyunsaturated (PUFA) fatty acids, acidity, PV and conjugated trienes had positive influence, while TPC, TFR, CAR, monounsaturated fatty acid (MUFA), and MUFA/PUFA ratio showed negative contributions. Thus, only few samples satisfied the ideal quality and nutritional requirements of edible oils.

Microfluidic Microwave Sensor Loaded with Star-Slotted Patch for Edible Oil Quality Inspection.

In this paper, we present a new microfluidic microwave sensor loaded with a star-slotted patch for detecting the quality of edible oil. The relative dielectric permittivity and the quality of edible oil will change after being heated at a high temperature. Therefore, the quality of edible oil can be detected by measuring the relative dielectric permittivity of edible oil. The sensor is used to determine the edible oil with different dielectric permittivity by measuring the resonance frequency offset of the input reflection coefficient, which operates at 2.68 GHz. This sensor is designed based on a resonant approach to provide the best sensing accuracy and is implemented using a substrate integrated waveguide structure combined with a pentagonal slot antenna operating at 2.3~2.9 GHz. It can detect greasy liquids with the real part of the complex permittivity ranging from two to three.

Characterization and Modeling Quality Analysis of Edible Oils Using Electrochemical Impedance Spectroscopy.

The dielectric characteristics of six culinary oils were measured over the frequency range of 0.01 Hz–100 kHz. The results showed that the dielectric constants of oils had the same frequency relationship (i.e., they decreased with increasing frequency). The dielectric constants at lower frequencies for olive oil A, olive oil B, sesame oil, Nigella sativa, sunflower oil, and corn oil are approximately 2.75, 2.5, 2.0, 1.75, 1.5, and 0.9. An FT-IR analysis showed that the spectral differences were very small, because most vegetable oils contain the same type of fatty acids. The model built using COMSOL Multiphysics for the potential and electric field distributions for different oils and used to calculate the dielectric constant was simulated under various conditions in the AC/DC module. The model results were compared with the experimental results, which showed satisfactory convergence between them. The experimental and model results obtained in this study could be useful for evaluating the edible oil quality.