Rapid determination of trans-resveratrol in vegetable oils using magnetic hydrophilic multi-walled carbon nanotubes as adsorbents followed by liquid chromatography-tandem mass spectrometry

Current analytical strategies for the determination of resveratrol in foods

Resveratrol, a non-flavonoid polyphenolic compound, possesses various beneficial properties such as anti-cancer, anti-aging, anti-bacterial, and antioxidant effects. It is naturally produced by many plants in response to stimulation. However, the content of resveratrol in natural plants can vary significantly, ranging from micrograms to milligrams per kilogram. As the demand for resveratrol increases, the development of methods for extracting and quantifying resveratrol in food has become a rapidly growing field in recent years. This review aims to comprehensively summarize the progress made in resveratrol analysis in food over the past decade (2012-2022), with a specific focus on the latest advancements in extraction and detection technologies. The objective is to offer a valuable reference for further research and utilization of resveratrol in various food applications.

Recent Progress on Green New Phase Extraction and Preparation of Polyphenols in Edible Oil

With the proposal of replacing toxic solvents with non-toxic solvents in the concept of green chemistry, the development and utilization of new green extraction techniques have become a research hotspot. Phenolic compounds in edible oils have good antioxidant activity, but due to their low content and complex matrix, it is difficult to achieve a high extraction rate in a green and efficient way. This paper reviews the current research status of novel extraction materials in solid-phase extraction, including carbon nanotubes, graphene and metal-organic frameworks, as well as the application of green chemical materials in liquid-phase extraction, including deep eutectic solvents, ionic liquids, supercritical fluids and supramolecular solvents. The aim is to provide a more specific reference for realizing the green and efficient extraction of polyphenolic compounds from edible oils, as well as another possibility for the future research trend of green extraction technology.

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.

Screening of new psychoactive substances in human plasma by magnetic solid phase extraction and LC-QTOF-MS

The emergence of new psychoactive substances (NPSs) is an increasing challenge in forensic toxicology. There are many extraction methods in use to isolate NPSs in biological fluids, including protein precipitation (PPT), liquid-liquid extraction (LLE), and solid phase extraction (SPE). However, there is a need to develop an effective extraction method with a short extraction time and low consumption of solvent. To meet these requirements, magnetic solid phase extraction (m-SPE) was attempted to isolate 40 NPSs in human plasma in this study. Forty NPSs (13 synthetic cannabinoids, 13 phenethylamines, 4 tryptamines, 4 other substances, 3 aminoindanes, 2 piperazines, 1 phencyclidine-type substance) were spiked in plasma and analyzed by m-SPE using COOH-functionalized multi-walled carbon nanotubes with magnetic nanoparticles (COOH-mMWCNTs). A liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) method was used for screening and identification of 40 target compounds. Method validation including limits of detection, recovery, matrix effect, and precision was performed for all 40 -target compounds. The limits of detection (LOD) of the 40 analytes were between 0.002 and 0.084 mg/L. Extraction recovery ranged from 36.9% to 110.6% (average 87%). Matrix effects ranged from -29.0% (ion suppression) to 9.8% (ion enhancement). Both intra- and inter-day precision values were less than 27.5% (RSD%). The accurate mass of QTOF-MS enabled the identification of analytes by exact monoisotopic mass and isotopic pattern. m-SPE was applied to extract 40 NPSs, and revealed less time-consuming and laborious than conventional SPE. This method proved to be an advantageous procedure to extract NPSs from biological fluids.

A comprehensive review on different classes of polyphenolic compounds present in edible oils

Edible oils are used as a frying medium and in the preparation of several food products. They are mainly constituting triacylglycerols as major components, while other compounds are classified as minor constituents, which include polyphenols. This class of compounds plays an important role in the thermal stability and quality attributes of the finished industrial food products. In addition to other antioxidants, the desired thermal stability of edible is achieved by either fortification or mixing of edible oils. This comprehensive review was therefore aimed to review the different classes of polyphenolic compounds present in commonly consumed edible oils. The edible oils reviewed include soybean, olive, rapeseed, canola, sunflower, flaxseed, sesame, cottonseed, palm, almond, peanut, chestnut, coconut, and hazelnut oils. The identified classes of polyphenolic compounds such as simple phenols, hydroxybenzoic acids, phenylethanoids, hydroxycinnamic acid, esters of hydroxycinnamic acids, coumarins & chromans, stilbenes, flavonoids, anthocyanins, and lignans were discussed. It was observed that a single edible from different origins showed the varied composition of the different classes of phenolic compounds. Among the oils, soybean, sunflower, olive, and brassica oils received higher attention in terms of polyphenol composition. Some classes of phenolic compounds were either not reported or absent in one edible oil, while present in others. Among the different classes of phenolics, hydroxybenzoic acids, hydroxycinnamic acid and flavonoids were the most widely present compounds. Phenolic compounds in edible oils possess several health benefits such as antioxidant, antibacterial, anti-viral, anti-inflammatory, anti-tumour, antioxidants, cardioprotective, neuroprotective, anti-diabetic properties and anti-obesity.

Magnetic Solid-Phase Extraction of Drugs and Pesticides from Human Plasma Using COOH-mMWCNTs

Carbon nanotubes (CNTs) are useful for extracting chemical compounds due to their properties, such as surface area and the potential for chemical modification. Especially the formation of CNTs with carboxylic acid functional group makes them disperse in water-based samples and have strong interaction forces with cationizable analytes. Based on these features, carboxylic acid functionalized multi-walled CNTs (COOH-MWCNTs) have been used as extraction sorbents. CNT can also be gathered using an external magnet by forming complex with iron oxide (Fe3O4) magnetic nanoparticles (MNPs). In this study, COOH-MWCNTs with MNPs were subjected to magnetic solid-phase extraction (mSPE) in order to extract the targeted substances such as diphenhydramine, doxylamine, tramadol, escitalopram, zolpidem, diphenamid, paclobutrazol, hexaconazole, cyproconazole and mepronil from human plasma samples. The following five factors were optimized: (i) the ratio of COOH-MWCNTs to MNPs as a sorbent from 1:1 to 1:4; (ii) sorbent amount starting from 12.5 to 75%; (iii) sample pH tested pH 2 to pH 10 with 1 N hydrochloride and 1 N sodium hydroxide; (iv) agitating time from 0 to 4 min and (v) elution solvent. Limit of detection of 10 targeted substances in human plasma were in the range of 0.1-0.4 mg/L. The recovery of targeted substances (except diphenamid) in human plasma was 73.06-110.28% for intra-day and 83.00-107.70% for inter-day and the precision (relative standard deviation, %) in human plasma was 0.3-13.3% for intra-day and 2.9-15.6% for inter-day. The method was applied to nine authentic biological samples from overdose patients in the emergency room of Chungnam National University Hospital. The performance of mSPE was compared with the liquid-liquid extraction method using ethyl acetate. The results showed that the newly developed method in this study can be used for screening analysis in forensic and clinical toxicology.

Extraction of betacyanins from Hylocereus polyrhizus (dragon fruit) peel and further enrichment by adsorption

Mixtures of water and ethanol were tested for the extraction of betacyanins from Hylocereus polyrhizus peel to obtain natural colorants. In order to obtain betacyanins in a purified form, adsorption was carried out with two types of multi-walled carbon nanotubes (MWCNTs; pristine MWCNTs and carboxylated MWCNTs) and two macroporous resins (X-5 and AB-8). Carboxylated MWCNTs showed the highest adsorption capacity. On the basis of static adsorption test, carboxylated MWCNTs were selected for kinetic and isotherm studies. Langmuir and pseudo-first-order models could describe the process well. According to the Langmuir model, the maximum monolayer adsorption amount of carboxylated MWCNTs was 84.6 mg/g. After purification on a chromatographic column packed with carboxylated MWCNTs, the content of H. polyrhizus peel betacyanins in the pigment product was 4.62%.

Application of natural cotton fibers as an extraction sorbent for the detection of trans-resveratrol in adulterated peanut oils

The current study develops an effective, convenient, low-cost, and environmentally friendly method for determining trans-resveratrol (TRA) in peanut oils, the unique proportion of peanut oil, by employing natural cotton fibers without any pretreatment as extraction sorbent and an in-syringe extraction device. The primary factors affecting the extraction recovery are optimized in detail. The condition of 200.0 mg of cotton fibers, six push-pull times, 2.0 mL of n-hexane as washing solvent and 2.0 mL of ethanol as desorption solvent is selected as the best. The linear range is demonstrated to be 10-1000 ng/g with a satisfactory correlation coefficient (R² = 0.9995), while the limit of detection is calculated as 2.47 ng/g. In addition, the recoveries of TRA are obtained in the range of 93.8-104.4% with RSDs less than 5.5%. Finally, the developed method is successfully applied to determine TRA concentrations in commercial peanut oils and other edible oils.

Synergistic effects of layer-by-layer films for highly selective and sensitive electrochemical detection of trans-resveratrol

Trans-resveratrol (TRA) possesses a variety of pharmacological activities, making important to explore simple, inexpensive, and reliable analytical methods for identification and quantification of it. We report on the synergistic effects originated from layer-by-layer films of graphene (Gr)-gold nanoparticles (Au) and molecularly imprinted polymers (MIPs) modified glassy carbon electrode (GCE) for electrochemical detection of TRA. To construct the TRA electrochemical sensor (GCE|Gr-Au/MIPs), the films of Gr-Au, MIPs were step by step formed onto GCE via in-situ and controllable electrodeposition and polymerization processes. The compositions, morphologies, and electrochemical properties of obtained films were investigated by various methods. Under the optimized experimental conditions, the electrochemical sensor showed superior performance toward selective and sensitive determination of TRA with K₃[Fe(CN)₆] as electrochemical signal probe. The electrochemical sensor was applied to determine TRA in real samples with good accuracy and recovery, verifying the broad and practical application prospects for foods and medicines analysis.

Determination of Aflatoxin B1 and B2 in Vegetable Oils Using Fe3O4/rGO Magnetic Solid Phase Extraction Coupled with High-Performance Liquid Chromatography Fluorescence with Post-Column Photochemical Derivatization

In this study, magnetic graphene nanocomposite Fe3O4/rGO was synthesized by facile one-pot solvothermal method. The nanocomposite was successfully used as magnetic solid phase extraction (MSPE) adsorbents for the determination of aflatoxins in edible vegetable oils through the π-π stacking interactions. MSPE parameters including the amount of adsorbents, extraction and desorption time, washing conditions, and the type and volume of desorption solvent were optimized. Under optimal conditions, good linear relationships were achieved. Limits of detection of this method were as low as 0.02 µg/kg and 0.01 µg/kg for aflatoxin B1 and B2, respectively. Finally, the magnetic graphene nanocomposite was successfully applied to aflatoxin analysis in vegetable oils. The results indicated that the recoveries of the B-group aflatoxins ranged from 80.4% to 106.0%, whereas the relative standard deviations (RSDs) were less than 8.1%. Owing to the simplicity, rapidity and efficiency, Fe3O4/rGO magnetic solid phase extraction coupled with high-performance liquid chromatography fluorescence with post-column photochemical derivatization (Fe3O4/rGO MSPE-HPLC-PCD-FLD) is a promising analytical method for routine and accurate determination of aflatoxins in lipid matrices.

Multispecies Adulteration Detection of Camellia Oil by Chemical Markers

Adulteration of edible oils has attracted attention from more researchers and consumers in recent years. Complex multispecies adulteration is a commonly used strategy to mask the traditional adulteration detection methods. Most of the researchers were only concerned about single targeted adulterants, however, it was difficult to identify complex multispecies adulteration or untargeted adulterants. To detect adulteration of edible oil, identification of characteristic markers of adulterants was proposed to be an effective method, which could provide a solution for multispecies adulteration detection. In this study, a simple method of multispecies adulteration detection for camellia oil (adulterated with soybean oil, peanut oil, rapeseed oil) was developed by quantifying chemical markers including four isoflavones, trans-resveratrol and sinapic acid, which used liquid chromatography tandem mass spectrometry (LC-MS/MS) combined with solid phase extraction (SPE). In commercial camellia oil, only two of them were detected of daidzin with the average content of 0.06 ng/g while other markers were absent. The developed method was highly sensitive as the limits of detection (LODs) ranged from 0.02 ng/mL to 0.16 ng/mL and the mean recoveries ranged from 79.7% to 113.5%, indicating that this method was reliable to detect potential characteristic markers in edible oils. Six target compounds for pure camellia oils, soybean oils, peanut oils and rapeseed oils had been analyzed to get the results. The validation results indicated that this simple and rapid method was successfully employed to determine multispecies adulteration of camellia oil adulterated with soybean, peanut and rapeseed oils.

Chronic consumption of fructose in combination with trans fatty acids but not with saturated fatty acids induces nonalcoholic steatohepatitis with fibrosis in rats

PURPOSE

Consumption of Western diet high in fat and fructose has been attributed to the recent epidemic of nonalcoholic fatty liver disease (NAFLD). However, the impact of specific fatty acids on the progression of NAFLD to nonalcoholic steatohepatitis (NASH) is poorly understood. In the present study, we investigated the chronic effects of consumption of fructose in combination with saturated fatty acids (SFA) or trans fatty acids (TFA) on the development of NAFLD.

METHODS

Male Sprague-Dawley rats were randomly assigned to six isocaloric starch/high fructose (44% of calories), high fat (39% calories) diet containing either starch-peanut oil, fructose-peanut oil, fructose-palmolein, fructose-clarified butter, fructose-coconut oil or fructose-partially hydrogenated vegetable oil and fed for 24 weeks. Palmolein, clarified butter and coconut oil were used as the source of SFA whereas partially hydrogenated vegetable oil was used as the source of TFA. Peanut oil was used as the reference oil.

RESULTS

Long-term feeding of fructose in combination with SFA or TFA induced hepatic steatosis of similar extent associated with upregulation of stearoyl CoA desaturase-1. In contrast, fructose in combination with TFA induced NASH with fibrosis as evidenced by upregulation of hepatic proinflammatory cytokine and fibrogenic gene expression, increased hepatic oxidative stress and adipocytokine imbalance. Histopathological analysis revealed the presence of NASH with fibrosis. Further, peanut oil prevented the development of NAFLD in fructose-fed rats.

CONCLUSION

Fructose in combination with TFA caused NASH with fibrosis by inducing oxidative stress and inflammation, whereas, fructose in combination with SFA caused simple steatosis, suggesting that the type of fatty acid is more important for the progression of NAFLD.

Quality assessment of juice prepared from different varieties of currant (Ribes L.)

In the Slovak Republic currants are traditionally grown species of small fruits mainly in house gardens. Although currently their area is very small compared to the other types of fruit. We can see the importance of growing this genus (Ribes L.) in its good adaptability to climate conditions, in small growing demands and in stable production of nutritionally highly valuable fruit. Currant berries as well as fresh currant juice are characterized by the presence of whole complex of antioxidant active substances. The aim of this study was to evaluate the nutritional quality of currant juice prepared from various species and varieties of genus Ribes (L.). based on the content of their total polyphenols, anthocyanin dyes and antioxidant activity. In work we used varieties Blanka, Primus, Viktória, Heinemannova neskorá, Red Lake, Treny, Jonkheer van Tets, Fertödi, Titania, Triton and Öjebyn. Contents of evaluated components were assessed spectrophotometrically. Total polyphenol content of monitored samples determined by the Folin-Ciocalteu method reached values from 1897.43 mg GAE.dm-3 DM to 3712.21 mg GAE.dm-3 DM. The highest one was in juice from variety Primus and the lowest from variety Blanka. In white varieties of currant, the presence of anthocyanin dyes was immeasurable. In varieties of red and black currant anthocyanin dye content achieved values from 1947.64 mg.dm-3 DM (Jonkheer van Tets) to 4161.07 mg.dm-3 DM (Heinemannova neskorá). The antioxidant activity determined by the FOMO method reached values from 4130.42 mg AA.dm-3 DM to 6571.69 mg AA.dm-3 DM. We recorded the highest antioxidant activity in juice of variety Fertödi and the lowest of variety Primus.

Use of Pollen Solid-Phase Extraction for the Determination of trans-Resveratrol in Peanut Oils

In this study, a simple and convenient method for the determination of trans-resveratrol (TRA) in peanut oils based on pollen grain solid-phase extraction (SPE) was developed. Pollen grains were used as normal-phase SPE sorbent to separate TRA from peanut oils for the first time. As a naturally occurring material, pollen grains exhibited an excellent adsorption capacity for polyphenolic compounds due to their particular functional structures such as hydroxyl groups, saturated and unsaturated aliphatic chains with aromatics. Their stable compositions as well as adequate particle size (30-40 μm) also make them suitable for SPE. Several parameters influencing extraction performance were investigated. Coupled with high-performance liquid chromatography-ultraviolet detection (HPLC-UV), a green purification method for fast determination of TRA in peanut oils using pollen grain cartridges as sorbents was established. The linearity range of the proposed method was 10-2500 ng · g(-1) with a satisfactory correlation coefficient (r(2)) of 0.9999. The limit of detection (LOD) for TRA in peanut oils was 2.7 ng · g(-1), and the recoveries in spiked oil samples were from 70.2% to 98.4% with the relative standard deviations (RSDs) less than 4.9% (intraday) and 5.2% (interday). This method was successfully applied to the analysis of TRA in several peanut oils with different brands from local market as well as other kinds of vegetable oils.