Edible Oil Samples Research Articles

Application of IR and UV–VIS spectroscopies and multivariate analysis for the classification of waste vegetable oils

Due to the ever-increasing worldwide interest in the exploitation of waste vegetable oils, the development of analytical tools able to detect their adulteration with edible oils, is considered a priority for the scientific and industrial community. In this work, edible and waste vegetable oils have been analysed by Fourier Transform-InfraRed (FT-IR) and Ultraviolet-Visible (UV–VIS) spectroscopies and the corresponding spectral data subjected to statistical multivariate analysis for classification purposes. In particular, Principal Component Analysis (PCA) and Partial Least Square Discriminant Analysis (PLS-DA) were performed in order to develop an analytical tool which is able to distinguish between edible and waste vegetable oil. Qualitative analysis of the spectra suggested FT-IR and UV–VIS as the more suitable techniques to distinguish between wastes and edible samples. Also, statistical multivariate analysis revealed that FT-IR-based methodology is more adequate for the target, even if the elevated sensibility of the method produces an undesired distinction between edible oils of the same type. Finally, further attempts on UV–VIS data obtained in reflection mode allowed to produce a good dataset which after statistical treatment gave a clear differentiation between edible and waste oil samples.

Determination of 197 pesticide residues in edible vegetable oil by gas chromatography-time-of-flight mass spectrometry

建立了气相色谱-飞行时间质谱(GC-TOF-MS)同时测定食用植物油中197种农药残留的方法。样品经乙腈超声提取,冷冻除脂,C18和PSA吸附剂共同净化;目标物经HP-5MS UI毛细管柱(30 m×0.25 mm×0.25 μm)分离,电子轰击源电离,全扫描模式采集质谱信息;MassHunter软件对数据进行定性与定量分析,设置精确质量数偏差为±5×10-5,保留时间偏差为±0.1 min。实验考察了基质效应情况和方法学性能。结果表明,大多数农药表现出基质增强效应,需采用基质标准工作溶液进行定量。在优化的条件下,174种农药定量限可以达到0.01 mg/kg,占全部被测农药的88%,另外23种农药的定量限为0.025~0.1 mg/kg。除联苯的线性范围为2~100 μg/L外,其余农药的线性范围均为定量限~200 μg/L,相关系数(R2)均大于0.99。在3个添加水平(0.1、0.25和0.5 mg/kg)下,有156种农药的回收率为70%~120%,占全部被测农药的79%,有185种农药的相对标准偏差<10%,占全部被测农药的94%。应用该方法对23份市售植物油样品进行了检测,结果在12个样品中检出13种农药。该方法操作简便,一次进样即可实现近200种农药的同时检测,且检测结果的准确度和灵敏度良好,适用于食用植物油中197种农药残留的快速检测。

Assessment of Quality Parameters in Edible Vegetable Oils

Objectives: Edible oils, derived from a plant source, play a vital role in providing nutrition. A quality edible oil has a flavor, range of physicochemical parameters. Several quality parameters like saponification value, acid value, peroxidase value and iodine value will be helpful in estimating the quality of edible vegetable oils. The present study was intended to evaluate the quality difference between cooked and uncooked oils. Materials and Methods: Utilizing various edible oil samples from major brands in india e.g sunflower oil, soybean oil, canola oil, almond oil, coconut oil and, olive oil saponification value and acid value was determined. All the oil samples were thoroughly characterized by calculating their saponification value and acid value using the standard procedure of association of official analytical chemist (AOCS) and American oil chemist society. Results: In comparision to uncooked oils, cooked oils had significantly higher sapnification values. The acid values were also increased in cooked oils compared to uncooked oils. Widely used sunflower oil had a two fold significant increase in saponification value and five fold significant increase in acid value after cooking. Similar changes were not observed in olive oil. Conclusion: Taken together, results of our study indicate that widely used sunflower oil might not be appropraiate for domestic usage. Further, our results also indicate that olive oil might be a better choice for domestic cooking. Further studies are required for a large scale validation of the present results there by brining in regulation/public health policy on usage of cooked oils by various small scale food vendors.

Determination of aflatoxins in edible vegetable oils from Egyptian market: Method development, validation, and health risk assessment

Aflatoxins (AFs) are among the most toxic contaminants that are present in nuts, grains, seeds, and spices. This study developed a selective and reliable method to determine AFs in edible vegetable oils. In addition, the health risk assessments of AFs owing to the consumption of contaminated edible vegetable oils were estimated using the margin of exposure (MOE) approach in Egyptians. Size exclusion chromatography was performed for the selective extraction of AFs from oils. AFs were quantified via precolumn derivatization, followed by high-performance liquid chromatography with a fluorescence detector (HPLC-FLD). The method was tested for validation parameters and was found to fit its selective and intended use. The limit of quantification (LOQ) values for AFG1, AFB1, AFG2, and AFB2 were 0.3, 0.3, 0.4, and 0.2 μg kg−1, respectively; the corresponding values for the limit of detection (LOD) were 0.08, 0.08, 0.11, and 0.07 μg kg−1, respectively. The test method was applied to determine AFs in 90 randomly collected edible vegetable oil samples from 4 Egyptian governorates. The results showed that 5.6 % of the samples were contaminated with AFB1 (average concentration, 3.56 ± 2.50 μg kg−1). The estimated daily intakes of AFB1 from sunflower, corn, and mixed oils were 0.00047, 0.00571, and 0.30384 ng kg−1 body weight (bw) day−1, respectively, and the corresponding MOE values were 361,702, 29,750, and 560 ng kg−1 bw day−1, respectively. The MOE results suggested that the situation represents a health concern regarding the consumption of mixed oils and that essential measures should be taken to protect public health. However, no harmful effects from the consumption of sunflower and corn oils were observed. This is the first study to investigate AFs in edible vegetable oils and assess their health risk in Egypt.

Air-assisted liquid-liquid microextraction of total 3-monochloropropane-1,2-diol from refined edible oils based on a natural deep eutectic solvent and its determination by gas chromatography-mass spectrometry

In this paper, a fast, sensitive, and selective sample preparation procedure was presented for the determination of 3-monochloropropane-1,2-diol (3-MCPD) in refined edible oils using gas chromatography-mass spectrometry. In this method, firstly, the sample lipids and analyte fatty esters are saponified by sodium hydroxide under sonication. After that the analyte was derivatized using phenylboronic acid (as the derivatization agent) and the obtained derivative was extracted during an air-assisted liquid-liquid microextraction procedure (AALLME). Six different deep eutectic solvents (DESs) were prepared as the extraction solvents and the most effective extraction for 3-MCPD was obtained in the presence of a natural DES (NDES) consisting of choline chloride (ChCl)-acetic acid (AcOH). Important variables such as sodium hydroxide concentration and volume, sonication time, temperature, extraction solvent type and volume, and phenylboronic acid concentration and volume have been optimized. Using the optimum conditions, broad linear range (0.88-1000 ng g–1), suitable coefficient of determination (0.995), and low limits of detection (0.26 ng g–1) and quantification (0.88 ng g−1) were obtained. Relative standard deviations for intra– (n=8) and inter-day (n=6) precisions at a concentration of 5 ng g−1 were 2.6 and 3.2%, respectively. The developed method has been successfully applied to 3-MCPD determination in refined edible oil samples including sunflower, corn, and canola oils.

Imidazole-modified C6 -chitosan derivatives used to extract β-sitosterol from edible oil samples with a microwave-assisted solid phase extraction method.

β-Sitosterol is a major bioactive constituent in plants with potent anticancer effects against many human cancer cells, but its bioavailability and therapeutic efficacy are limited by its poor solubility in water. In this study, C6 -imidazole chitosan, C6 -1-methylimidazole chitosan, C6 -1-ethylimidazole chitosan, C6 -1-vinylimidazole chitosan, C6 -1-allylimidazole chitosan, and C6 -1-butylimidazole chitosan were prepared to extract β-sitosterol from edible oil samples via ultrasonic-assisted solid liquid extraction. The structures and properties of the newly synthesized products were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, and elemental analysis. The extraction abilities of the derivatives were tested in the experiment with high-performance liquid chromatography (limit of detection 0.21 μg/g and limit of quantification 0.67 μg/g), and the % relative standard deviation(<3.25%) and recovery values of the prepared chitosan derivatives toward β-sitosterol (average: 100.20%) were acceptable. The spiked interday and intraday recoveries of β-sitosterol were 102.60 ± 2.78 and 103.90 ± 3.04%, respectively. The actual amounts of β-sitosterol extracted from three real samples using C6 -imidazole chitosan according to the solid phase extraction method were 3302.40, 901.70, and 2045.60mg/kg for corn oil, olive oil, and pea oil, respectively.

Identification of olfactory characteristics of edible oil during storage period using metal oxide semiconductor sensor signals and ANN methods

In this study, an electronic nose coupled with artificial neural network (ANN) was used to predict the shelf life of two oil with new production date and oil with old production date over a period of 150 days. According to the American Oil Chemists’ Society results, the oils were oxidized after 60 days. Principal component analysis results indicated that all the oil samples were correctly discriminated from each other during their storage times, and samples of oxidized and nonoxidized oils can be properly distinguished from each other. Two main components (PC1, PC2) managed to describe 97% of the data set variance concerning the shelf life of the oil. To develop the ANN models, the data were first divided into three groups: training (60%), validation, and test (40%). To determine the best model, two criteria (R2 and root mean square error) were used. The results revealed that the ANN model can be used as a powerful tool for pattern recognition and determination of the shelf life of oil and its oxidation degree at high precision. Scientific and feasible results can be obtained by matching ANN and the results obtained by metal oxide semiconductor sensors of E-nose. Practical applications One of the most important causes of food spoilage is lipid oxidation. The American Oil Chemists’ Society (AOCS) has developed a variety of methods for assessing the state of food oxidation. In this study, oil shelf life studied by a combination of artificial senses and chemometrics methods. The acidity, peroxide, anisidine, and Totox values of the edible oil samples were measured according to the AOCS standard. Principal component analysis and artificial neural neural methods succeeded in classifying the samples based on their storage time with high accuracy.

Reversed-phase switchable-hydrophilicity solvent liquid-liquid microextraction of copper prior to its determination by smartphone digital image colorimetry

Reversed-phase switchable-hydrophilicity solvent liquid-liquid microextraction (RP-SHS-LLME) was used prior to smartphone digital image colorimetry (SDIC) for the determination of copper as its metal chelate with N,N-diethyl-N’-benzoylthiourea (DEBT). Images of the extract were captured inside a colorimetric box, which were split into their red-green-blue channels and the intensity of the blue channel was linearly correlated to the concentration of copper. The optimum SDIC conditions were achieved at a wavelength of 400 nm, a distance of 7.0 cm between the sample holder and the detection camera, a region of interest of 2500 px2 and light source brightness of 30.0 %. Optimum RP-SHS-LLME performance was realized with 80.0 μL of triethylamine as a switchable-hydrophilicity solvent, 140.0 μL of 7.5 mol L−1 nitric acid as a hydrophilicity-switching trigger, at a complexation pH of 5.5, 200 μL of DEBT and 200 μL of 1-dodecanol as the complexation solvent within 4.0 min. The limit of detection (LOD) was found as 0.3 μg mL−1 with coefficients of determination of the calibration graphs higher than 0.9963 and relative standard deviations lower than 6.9 %. The proposed method was applied for the determination of copper in edible oil samples (i.e., black seed, corn, olive and sunflower oil), with percentage relative recoveries obtained in the range of 92.5–105.0 %.

Microwave Spoof Surface Plasmon Polariton-Based Sensor for Ultrasensitive Detection of Liquid Analyte Dielectric Constant.

In this paper, a microwave microfluidic sensor based on spoof surface plasmon polaritons (SSPPs) was proposed for ultrasensitive detection of dielectric constant. A novel unit cell for the SSPP structure is proposed and its behaviour and sensing potential analysed in detail. Based on the proposed cell, the SSPP microwave structure with a microfluidic reservoir is designed as a multilayer configuration to serve as a sensing platform for liquid analytes. The sensor is realized using a combination of rapid, cost-effective technologies of xurography, laser micromachining, and cold lamination bonding, and its potential is validated in the experiments with edible oil samples. The results demonstrate high sensitivity (850 MHz/epsilon unit) and excellent linearity (R2 = 0.9802) of the sensor, which, together with its low-cost and simple fabrication, make the proposed sensor an excellent candidate for the detection of small changes in the dielectric constant of edible oils and other liquid analytes.

Occurrence of Aflatoxins in Edible Vegetable Seeds and Oil Samples Available in Pakistani Retail Markets and Estimation of Dietary Intake in Consumers.

Aflatoxins (AFs) are secondary metabolites toxic to humans as well as animals. The environmental conditions, conventional agricultural practices, and illiteracy are the main factors which favor the production of AFs in food and feed. In the current study 744 samples of vegetable seeds and oils (soybean, sunflower, canola, olive, corn, and mustard) were collected and tested for the presence of aflatoxin B1 (AFB1) and total AFs. Liquid-liquid extraction was employed for the extraction of AFs from seeds and oil samples. Reverse phase high performance liquid chromatography equipped with fluorescence detection was used for the analysis. The results have shown that 92 (56.7%) samples of imported and 108 (57.0%) samples of local edible seeds were observed to be contaminated with AFs. All samples of edible seeds have AFB1 levels greater than the proposed limit set by the European Union (EU, 2 µg/kg) and 12 (7.40%) samples of imported seeds and 14 (7.40%) samples of local seeds were found in the range ≥ 50 µg/kg. About 78 (43.3%) samples of imported edible oil and 103 (48.3%) sample of local edible oil were observed to be positive for AFs. Furthermore, 16 (8.88%) and six (3.33%) samples of imported vegetable oil have levels of total AFs in a range (21–50 µg/kg) and greater than 50 µg/kg, respectively. The findings indicate significant differences in AFs levels between imported and local vegetable oil samples (t = 22.27 and p = 0.009) at α = 0.05 and a significant difference in AFs levels were found between vegetable seeds and oil samples (t = −17.75, p = 0.009) at α = 0.05. The highest dietary intake was found for a local sunflower oil sample (0.90 µg/kg/day) in female individuals (16–22 age group). The results have shown considerably high levels of AFB1 and total AFs in seeds and oil samples and emphasise the need to monitor carefully the levels of these toxic substances in food and feed on regular basis.

Combination of cold induced HLLME with an effervescence-assisted DLLME based on deep eutectic solvent decomposition; application in extraction of some pyrethroid and carbamate pesticides from edible oils

ABSTRACT A cold-induced homogenous liquid–liquid microextraction method combined with solidification of floating organic droplets effervescent-assisted dispersive liquid–liquid microextraction has been developed for simultaneous extraction of several pyrethroid and carbamate pesticides from edible oils. The extracted analytes were determined by high performance liquid chromatography-diode array detector. For this purpose, 5 mL of edible oil sample was transferred into a glass test tube and it was mixed with 150 µL α-terpineol: acetic acid deep eutectic solvent. After vortexing (for 5 min), the mixture was placed into an ice: sodium chloride bath to adjust the solution temperature at −16℃. In this step, the oil sample was solidified, and the deep eutectic solvent was collected on top of the oil. Thus, it was collected and dispersed into 5.0 mL sodium carbonate solution at a concentration of 1.0 mol/L containing 2.5% w/v sodium chloride. In this step, the deep eutectic solvent was decomposed in the solution and α-terpineol dispersed in the sample solution. To obtain high extraction efficiency the effective parameters were optimised and under optimal conditions, the method showed broad linear ranges (2.6–500 ng/mL) with good coefficient of determinations ≥0.994. The extraction recoveries and enrichment factors of the method were in the ranges of 78–93% and 98–116%, respectively. The limits of detection and quantification were within the range of 0.2–0.8 and 0.6–2.6 ng/mL, respectively. The method was successfully used for the determination of the analytes in different edible oil samples.

A One-Dimensional U-Net-Based Calibration-Transfer Method for Low-Field Nuclear Magnetic Resonance Signals.

The reconstruction of the statistical analysis model of an instrument is a time-consuming and expensive process. Herein, the feasibility of spectral model calibration-transfer application to the same type of low-field nuclear magnetic resonance (LF-NMR) instrument was investigated using a one-dimensional U-net (1D U-net). Unlike conventional calibration-transfer algorithms such as direct standardization (DS), the 1D U-net network can reduce the error between the master and slave instruments through iterative cycles. The calibration-transfer ability was verified; three experiments that entailed the use of edible oil and copper sulfate (CuSO4) samples were implemented. The analysis of the spectral responses and feature analysis of the edible oil samples revealed that the signal of the slave instrument calibrated using the 1D U-net most resembled the signal of the master instrument, and its relative residual value was reduced to 0.0045. Further analysis of the CuSO4 concentration prediction showed that on the support vector regression (SVR) model constructed using the master instrument, the signal of the slave instrument calibrated by the 1D U-net was more similar to the response of the master instrument, and its root mean square error (RMSE) was only 0.01606 mmol/L. Thus, 1D U-net is a viable candidate for calibration-transfer applications to LF-NMR instruments.

Monitoring of aflatoxins in edible vegetable oils consumed in Western Iran in Iran: a risk assessment study

ABSTRACT Edible vegetable oils as an important component of our daily diet are widely consumed around the world. In this research, the concentrations of aflatoxins, including B1 (AFB1), B2 (AFB2), G1 (AFG1) and G2 (AFG2) were measured in 43 edible vegetable oil samples such as peanut oil (n = 18), sesame oil (n = 15), olive oil and (n = 10) using high-Performance liquid chromatography with fluorescence detector (HPLC- FLD). In addition, health risks of aflatoxins in adults and children due to ingestion of edible oils were calculated using the Margin of Exposure Estimation (MOE) by the Monte Carlo simulation (MCS) model. The results indicated that the total aflatoxin (TAF) and AFB1 concentrations in 30 (69.76%) and 29(67.14%) of the samples were in the ranges 0.09–30.95 µg/kg and 0.04–20.56 µg/kg, respectively. Also, the concentrations ofTAF and AFB1 in 18 and 16 samples were higher than the European Union maximum permissible limit, which were 4 and 2 µg/kg, respectively.While according to risk assessment analysis, the consumption of edible vegetable oils in children was safe. MOE values of aflatoxin through the consumption of edible vegetable oils in adult were lower than 10,000, showing that the adult are at considerable liver cancer risk. Therefore, it is necessary to strict inspection and monitoring of edible oil products by the regulatory bodies.

A sensitive HPLC-FLD method for the quantitative determination of 3-chloro-1,2-propanediol by pre-column fluorescence derivatization with 9-(2-Hydroxypropyl)adenine

In this paper, a sensitive method for the determination of 3-chloro-1,2-propanediol (3-MCPD) by high performance liquid chromatography-fluorescence detection (HPLC-FLD) was established, in which 9-(2-Hydroxypropyl) adenine (HP-Ade) was selected as the fluorescent derivatization reagent because of its good water solubility and hydrophobicity. The principle of the method lies in the origination of chloroacetaldehyde with the periodate oxidation of 3-MCPD and its' fluorescence derivatization by HP-Ade to produce a strong fluorescent substance, name as 1-N6 -vinylidene-9-(2-hydroxypropyl)adenine (ε-HP-Ade), used for quantitative determination of 3-MCPD by HPLC-FLD. Some mobile phase conditions and incubation parameters related with the method features were studied and optimized. Under the optimal conditions, the method shows high sensitivity, good linearity (r 2 = 0.999) and good repeatability (RSD% between 1.04% and 2.55%), the detection limit (LOD) and quantification limit (LOQ) were 0.02 ng/mL and 0.06 ng/mL respectively. It has been successfully applied for the determination of various edible vegetable oil samples, the chromatogram shows symmetrical peak shape, perfect separation and very “clean” profiles. In comparison with gas chromatography-mass spectrum (GC-MS), the pretreatment process of the proposed method was totally operated in aqueous phase, the instrument requirements and cost are relatively lower, thus it will provide another choice for the routine analysis of 3-MCPD.

Organic solvent-free elevated temperature liquid–liquid extraction combined with a new switchable deep eutectic solvent-based dispersive liquid–liquid microextraction of three phenolic antioxidants from oil samples

An organic solvent-free extraction procedure using elevated temperature liquid–liquid extraction/ dispersive liquid–liquid microextraction based on deep eutectic solvent has been performed for the extraction of three synthetic phenolic antioxidants from oil samples. In the developed approach, firstly the antioxidants were extracted into an aqueous alkaline solution in an elevated temperature. Then, a few microliters of deep eutectic solvent formed from tetrabutylammonium chloride and hydroquinone was dissolved in the alkaline solution and a homogenous solution was obtained. In the following it was dispersed into an acidic solution. In this step, an acid–base reaction was occurred and the analytes were migrated into the fine droplets of the deep eutectic solvent. The extracted analytes were determined by gas chromatography-flame ionization detector. Validation data showed that low limits of detection (0.13–0.42 ng/mL) and quantification (0.36–1.41 ng/mL), high extraction recovery (74–89%) and enrichment factor (370–445), and good precision (relative standard deviation ≤ 7.4%) can be obtained by the developed method. Finally, the method was used for quantification of the antioxidants in several edible oil samples.

An effective and rapid magnetic nanoparticle based dispersive solid phase extraction method for the extraction and preconcentration of cadmium from edible oil samples before ICP OES measurement

In this study, a new and efficient sample pretreatment method called as dispersive solid phase extraction (DSPE) was proposed for the extraction and preconcentration of cadmium from edible oil samples and combined with inductively coupled plasma-optical emission spectrometry (ICP OES) for analyte determination at trace levels. Stearic acid coated-Fe3O4 magnetic nanoparticle (SA-MNP) was selected as the best adsorbent for the preconcentration of analyte. Under the optimum experimental conditions, analytical performance of DSPE-ICP OES system for the analyte was evaluated in terms of limit of detection (LOD), limit of quantification (LOQ) and dynamic range. LOD/LOQ values for sunflower oil/olive oil and hazelnut oil matrices were determined as 0.14/0.46 μg/kg and 0.38/1.28 μg/kg, respectively. In order to test the accuracy and applicability of DSPE-ICP OES method, recovery studies were performed in edible oils (sunflower oil, olive oil and hazelnut oil). The recovery results for sunflower oil, olive oil and hazelnut oil samples were calculated as 92.6–114.9 %, 85.0–104.3 % and 92.1–126.0 %, respectively.

Front Face Fluorescence Spectroscopy Combined with PLS‐DA Allows to Monitor Chemical Changes of Edible Vegetable Oils during Storage at 60 °C

AbstractIn this work, front‐face fluorescence spectroscopy coupled with chemometric tools are used for the monitoring of rapeseed, sunflower, extra virgin olive, and linseed oil. The oil samples are heated at 60 °C for up to 15 days. The fluorescence excitation spectra are scanned in the range of 270–420 nm and 250–310 nm after emission wavelength set at 450 and 330 nm, respectively. The primary and secondary lipid oxidation products are also determined on the same oil samples. By applying partial least square discriminant analysis (PLS‐DA) to each spectral collection obtained after emission set at 450 and 330 nm, clear discrimination of edible oil samples according to their botanical types, and sometimes aging, is obtained.Practical Applications: This study shows that oxidation of rapeseed, sunflower, extra virgin olive, and linseed oil monitored different trends due to their difference in composition. The presented results demonstrated the capability of the front‐face fluorescence spectroscopy to differentiate four vegetable oils contained in capped and uncapped flasks indicating the evolution of primary and secondary indicators of oxidation during the storage period. The technology can be exploited at the industrial level for monitoring in a non‐destructive manner the level of oxidation of edible oil.

Cobalt doped nitrogenous porous carbon derived from covalent organic framework as cataluminescence catalyst for rapid determination of n-hexane in edible oil

In this work, a catalytic material of cobalt doped nitrogenous porous carbon (Co/NPC) was fabricated from covalent organic frameworks (COFs) and cobalt ion via directly carbonization. Attribute to the excellent selective catalytic performance towards n-hexane, Co/NPC was employed in cataluminescence (CTL) for rapid and sensitive determination of n-hexane. Moreover, the detection conditions of CTL were evaluated, including temperature, flow rate and detecting wavelength. Under optimized conditions, a good linear relation between signal intensity of CTL and n-hexane concentration was obtained in the linear range of 0.4–250.0 mg/L and the limit of detection (LOD, S/N = 3) was 0.13 mg/L. Furthermore, the Co/NPC based CTL sensor was successfully applied to the determination of n-hexane in edible oil samples with the recoveries in the range of 92.0%–104.0%. The method comparison results of GC/MS and CTL on real sample analysis further proved the accuracy of the developed Co/NPC based CTL method. Additionally, the possible catalytic mechanism of n-hexane on the surface of Co/NPC was investigated, assisting by GC/MS on intermediation products identification. Overall, the Co/NPC based CTL sensor has been confirmed excellent performance in the n-hexane determination, which revealing extensive application in rapid residual n-hexane analysis in edible oil.

Quantitative Detection of Acid Value During Edible Oil Storage by Raman Spectroscopy: Comparison of the Optimization Effects of BOSS and VCPA Algorithms on the Characteristic Raman Spectra of Edible Oils

Acid value is one of the crucial indicators reflecting the quality of edible oil during storage. This study proposed a quantitative detection method for edible oil acid value during storage based on reduced Raman spectral characteristics. First, the Raman spectra of edible oil samples from different storage periods were collected, and the original spectra were preprocessed using Savitzky-Golay smoothing (SG smoothing), multiple scattering correction (MSC), adaptive iteratively reweighted penalized least squares (airPLS) combined with normalization. Then, bootstrap soft shrinkage (BOSS) and variable combination population analysis (VCPA) methods based on model population analysis (MPA) strategy were introduced to optimize Raman spectral characteristics. Finally, the SVM prediction model based on the optimized characteristic Raman shifts was established to realize the quantitative detection of edible oil acid value during storage. The results showed that compared with the full-spectrum SVM model, the BOSS-SVM and VCPA-SVM models had no overfitting during the training process, and the VCPA-SVM model obtained the best generalization performance, and its $$ {R}_{\mathrm{P}}^2 $$ and RMSEP in the prediction set were 0.932 and 0.153, respectively. This study sufficiently demonstrated that the SVM model integrated with the characteristic Raman shifts which were optimized by the BOSS and VCPA was a promising tool to monitoring the acid value in edible oil during the storage, and the characteristic Raman shifts of Raman spectra optimized by the VCPA was of more interpretation and pertinence.

Development of an Ion-Pair Dispersive Liquid-Liquid Microextraction Method Based on a Ternary Deep Eutectic Solvent for Determination of Some Herbicide Residues in Edible Oil Samples.

An ion-pair deep eutectic solvent (DES)-based dispersive liquid-liquid microextraction method was introduced and applied for the extraction of some acidic herbicides from edible oil samples prior to their determination by high performance liquid chromatography. First, a ternary DES composed of decanoic acid, dichloroacetic acid, and phosphocholine chloride is prepared under mild conditions. Then, the analytes are extracted into an alkaline solution from the oil samples by deprotonation of the herbicides. Afterward, the deprotonated analytes are extracted into the prepared DES with the aid of tri-butyl amine (as an ion-pair agent) in the presence of acetic acid (as a pH adjustment agent and dispersive solvent). The validation parameters indicated that the method has low limits of detection (0.09-0.72ngmL-1) and quantification (0.30-2.3ngmL-1), an acceptable percision (relative standard deviation≤ 9.0%) and high extraction recoveries (85-94%), and enrichment factors (566-626). The method was used in the analysis of 35 edible oil samples to assessment the studied analytes and the presence of haloxyfop was confirmed in three corn oils.