Glycidyl Fatty Acid Esters in Refined Edible Oils: A Review on Formation, Occurrence, Analysis, and Elimination Methods

Analysis of 3-MCPD and 1,3-DCP occurrence in mayonnaise: A probabilistic risk assessment of dietary exposure for Iranians

Mayonnaise is a commonly used oil-in-water emulsion food product. Due to their toxicological properties/genotoxicity and carcinogenicity, chloropropanols' oral exposure has raised concerns over the past decade. The present study reports the occurrence level of free forms of 3-chloropropane-1,2-diol (3-MCPD) and 1,3-dichloro-2-propanol (1,3-DCP) in mayonnaise samples and the risk of oral exposure to these chemicals through consumption of the analyzed samples. Mayonnaise (low- and high-fat, from 6 brands, totally 120 samples) were analyzed for 1,3-DCP and 3-MCPD by gas chromatography-mass spectrometry. The mean level of chemicals was higher in the high-fat samples, with no significant difference among the brands. Generally, 1,3-DCP level was significantly lower in both high-fat and low-fat samples compared to 3-MCPD. Hazard Index (HI) values calculated for oral exposure to 3-MCPD for Iranian adults using probabilistic methods, were less than 1.0, reflecting no major risk. In the Margin of Exposure scenario, low- and high-fat mayonnaise samples were of de minimis health concern at the 50th, 80th, and 95th centiles. Nevertheless, in order to safeguard consumer interests, it is imperative to implement online real-time methodologies for monitoring reactions that result in generation of thermal process contaminants such as 3-MCPD and 1,3-DCP, and to innovate novel technologies to minimize the occurrence of such chemicals while preserving both safety and sensory attributes.

Health risk assessment for dietary exposure to 3-monochloropropane-1,2-diol, 2-monochloropropane-1,2-diol, and glycidol for Italian consumers

3-Monochloropropane-1,2-diol (3-MCPD), 2-monochloropropane-1,2-diol (2-MCPD) and 2,3-epoxy-1-propanol (glycidol), in their free form or esterified to fatty acids, are food contaminants formed during the refinement of oils and fats. We conducted a survey to quantify the levels of these compounds in 130 food items, in order to assess the exposure to them in food and the consequent health risk for consumers. Food samples, including infant formula, were analysed by gas-chromatography mass spectrometry with the indirect method, and we used the latest open access food consumption database for the Italian population for a probabilistic assessment of exposure. We adopted an in silico approach to fill the gap for the toxicity of 2-MCPD. The occurrence values for the three contaminants in food were in most cases lower than or comparable to those reported in previous surveys. Exposure assessment for the most exposed individuals (95thpercentiles of consumers only) of different age groups, gave values below the tolerable daily intake recommended by the European Food Safety Authority for 3-MCPD and below the simulated or predicted toxicity thresholds for 2-MCPD, indicating a negligible risk due to dietary exposure to these contaminants. For glycidol, however, estimated exposure indicated a non-negligible increase in cancer risk, and a margin of exposure <25,000 for younger population groups, indicating a potential health concern.

Changes in stability, phytonutrients, 3-chloropropanol esters and glycidyl esters of peanut oil-based diacylglycerols during heat treatment

Diacylglycerol (DAG) is generally considered one of the precursors of 3-chloropropanol esters (3-MCPDE) and glycidyl esters (GEs). This study aimed to evaluate static heating and stir-frying properties of peanut oil (PO) and PO based 58% and 82% DAG oils (PDAG-58 and PDAG-82). Observations revealed that, phytonutrient levels notably diminished during static heating, with PDAG exhibiting reduced oxidative stability, but maintaining a stability profile similar to PO over a short period. During stir-frying, 3-MCPDE content initially increased and then decreased whereas the opposite was observed for GEs. Furthermore, as temperature, and NaCl concentration increased, there was a corresponding increase in the levels of 3-MCPDE and GEs, although remained within safe limits. When used in suitable concentrations, these findings underscore the potential of DAG, as a nutritionally rich and oxidatively stable alternative to conventional cooking oils, promoting the use of DAG edible oil in heat-cooked food systems.

Exposure to Dietary Glycidyl and 3-MCPD Fatty Acid Esters and Associated Burden of Cancer in Selected Asian and European Countries: A Review and Data Synthesis

This study evaluated the health implications and oncological impact of consuming glycidyl esters (GE) and 3-monochloro-1,2-propanediol esters (3-MCPDE) in selected Asian and European populations. Data on dietary GE and 3-MCPDE were compiled from 10 studies conducted in China, Taiwan, Poland, and Spain, identified through a systematic search in PubMed and ScienceDirect databases from 2012 to 2022. Studies on food supplements and analytical methods were excluded from the analysis. Health metrics for these nations, spanning 2015 to 2019, were sourced from the Institute of Health Metrics and Evaluation, among others. A Monte Carlo Simulation was employed for data analysis. The results showed that "grains and grain products" was the most consumed food category (260.45-395.35 g/day), whereas "food for infants and children" was the least consumed (0.01-0.09 g/day). Additionally, "fats from animal or plant origin" had the highest contamination levels. While 3-MCPDE exposures remained within safe limits, median GE exposure correlated with an incidence of colon cancer ranging from 3.66 × 10-8 to 0.744%, lung cancer from 0.00256 to 0.287%, and breast cancer from 0.0262 to 2.42% within the study areas. This translated to a total cancer burden of 6.69 to 1020 Disability-Adjusted Life Years (DALYs) per 100 000 individuals. The population in China recorded the highest DALY rate (1,020), followed by Spain (30.2), Poland (19.7), and Taiwan (6.69). Projections suggest an uptick in GE-related cancer cases and associated burdens in the coming decades attributed to demographic shifts, ageing populations, and dietary changes. The study underscores the urgency of mitigating GE and 3-MCPDE food contamination, bolstering public health awareness, and establishing safety guidelines.

Multiple Mechanisms of Haematococcus pluvialis-Derived Carotenoids to Inhibit Glycidyl Ester Formation in Rice Oil and a Chemical Model at High Temperatures

The common presence of glycidyl esters (GEs) in refined vegetable oils has been a concern for food safety. The present study aimed to investigate the inhibitory effects of three carotenoids derived from Haematococcus pluvialis microalga on GE formation in both rice oil and a chemical model during heating. The addition of astaxanthin (AS), lutein (LU), and β-carotene (CA) at 0.6 mg/g in rice oil can reduce GE formation by 65.0%, 57.1%, and 57.5%, respectively, which are significantly higher than those achieved by common antioxidants such as l-ascorbyl palmitate (39.0%), α-tocopherol (18.5%), tert-butyl hydroquinone (42.7%), and quercetin (26.2%). UPLC-Q-TOF-MS/MS analysis showed that two new compounds, that is, propylene glycol monoester and diester of palmitic acid, were formed in the CA-added chemical model, which provided direct experimental evidence for the inhibition of antioxidants including AS, LU, and CA against GE formation not only by indirect antioxidative action but also by direct radical reactions to competitively prevent the formation of cyclic acyloxonium intermediates. Furthermore, it was interestingly found that only AS could react with the GEs. The adduct of AS with GEs, astaxanthin-3-O-propanetriol esters, was preliminarily identified using Q-TOF-MS/MS in the heated AS-GE model, suggesting that reacting with GEs might represent another distinct mechanism of AS to eliminate GEs.

Occurrence of 3-monochloropropane-1,2-diol and glycidyl esters in artisanal vegetable edible oils

The safety of vegetable oils has come under intense scrutiny ever since the International Agency for Research on Cancer issued an alert on the carcinogenic properties of 3-monochloropropane-1,2-diol fatty acid esters (3-MCPDE) and glycidyl esters (GE). In this study, a total of 114 samples of artisanal palm oil (PO), palm kernel oil (PKO), and coconut oil (CO) were sourced from three regions in Ghana. The concentrations of 3-MCPDE and GE were quantified using the indirect method with gas chromatography-mass spectrometry. Subsequently, the statistical distribution functions of the concentrations of the esters were fitted using the Palisade @risk software. The relationships between the esters in the oils were determined using the Pearson correlation coefficient. The results showed no correlation (p > 0.05) between the concentrations of 3-MCPDE and GE. However, 18-60 % of the sampled PO contained 3-MCPDE above the European Commission's 2.5 mg/kg limit. In comparison, 24-35 % of the PO contained GE at levels exceeding the Commission's 1 mg/kg limit. Similarly, 25-35 % of PKO samples had GE concentrations above the limit. CO was the least contaminated oil, with little or no evidence of 3-MCPE and GE formation. Though the most frequently occurring (modal) concentrations of the esters were below the limits imposed by the Commission, it is the 95th percentile level of concentrations, especially for PO, that pose a health concern. Serious education and control must be exercised over the production of PO to enhance safety at the national and international markets.

Determination of chloropropanol esters and glycidyl esters in nutritional foods by gas chromatography-tandem mass spectrometry based on acid hydrolysis and solid-phase extraction

This study presents a method based on acid transesterification and the purification by solid-phase extraction (SPE) coupled with gas chromatography-tandem mass spectrometry for quantifying 3- and 2-monochloropropanediol esters (3-MCPDE, 2-MCPDE) and glycidyl esters (GE) in nutritional foods. The fat was extracted by liquid-liquid extraction with petroleum ether and diethyl ether after the sample was hydrolysed with ammonia. Then the extract was purified by a SPE cartridge filled with the aminopropyl sorbents. It was demonstrated that the optimal elution volume for 3-MCPDE, 2-MCPDE and GE greatly depended on the sample matrix and varied from 6 to 12 mL for four different kinds of food matrices. All three analytes in the sample solution could be fully collected in the first 10-12 mL of eluate. By this way, monoacylglycerols commonly present in the samples were fully removed. Therefore, the overestimation of GE quantification was effectively eliminated. The modified analytical procedure was fully validated in a single laboratory and has been recommended as a Chinese Food Safety National Standard. In addition, two derivatisation agents, heptafluorobutyrylimidazole and phenylboronic acid, were proved to be equivalent in method accuracy and precision for the quantification of three analytes.

Exposure to Chloropropanols and Their Fatty Acid Esters and Glycidyl Fatty Acid Esters in the Sixth Total Diet Study - China, 2016-2019

What is already known about this topic?

Chloropropanols, along with their fatty acid esters and glycidyl fatty acid esters (GEs), are prevalent contaminants in a variety of processed foods, posing potential health risks to humans.

What is added by this report?

In the Sixth China Total Diet Study (TDS), 3-monochloropropane-1,2-diol esters (3-MCPD esters) and GEs were identified as the predominant chloropropanols and their esters in composite food samples. Vegetables (47.0%) and cereals (15.4%) were the major contributors to exposure among the 12 food categories evaluated.

What are the implications for public health practice?

The Sixth China TDS highlighted concerns regarding potential health risks associated with dietary exposure to GEs. This study underscores the need for further attention in devising practical strategies to mitigate dietary exposure to GEs.

Determination of chloropropanol esters and glycidyl esters in instant noodles based on solid-phase microextraction with chitosan-β-cyclodextrin coated fiber

We developed a method for the determination of chloropropanol esters and glycidyl esters (GE) in instant noodles using solid-phase microextraction with chitosan-β-cyclodextrin (CS-β-CD) coated fiber coupled with gas chromatography-tandem mass spectrometry. The developed low-cost fiber coating can improve the sensitivity of the method. Immobilized enzymes can improve operational stability and reusability compared to free enzymes, thereby reducing costs. The adsorption isotherm was modeled using the Langmuir model, while the adsorption kinetics followed the pseudo second-order model. The limit of detection was 0.3 ng/L. The method exhibited satisfactory recoveries for the analytes, ranging from 80.2 % to 105.3 %, with relative standard deviations < 9.9 %. Furthermore, the results of the exposure assessment showed that chloropropanol esters do not pose unacceptable risks to different age groups. However, the margin of exposure for GE suggested a potential health risk for populations between the ages of 3 and 12 years old.

Determination of glycidyl fatty acid esters in edible vegetable oils by HPLC-ESI-QQQ-MS/MS combined with cryo-degreasing tandem dispersive solid-phase extraction

Glycidyl fatty acid esters (GEs) have been identified as food contaminants that can form during the processing and heating of edible oils. Their widespread occurrence raises potential concerns for consumers. This study aimed to develop a simple and effective analytical method for molecular recognition using mass spectrometry fragmentation patterns. Furthermore, it sought to simultaneously and quantitatively determine five common GEs in highly complex fatty matrices (oils) using high-performance liquid chromatography-triple quadrupole tandem mass spectrometry (HPLC-ESI-QQQ-MS/MS). An extraction method using acetonitrile was used, and the purification of the extract was optimized using cryo-degreasing-tandem dispersive solid-phase extraction (d-SPE) to eliminate fatty interferents. The method validation yielded recoveries ranging from 81.17% to 109.28% and the method precision was < 10.00%. The limits of quantification ranged from 0.08 to 0.21 ng/g, which is below the current legal limits. This approach may play a crucial role in ensuring food safety.

A comparison of the exposure system of glycidol-related chemicals on the formation of glycidol-hemoglobin adducts

Glycidol fatty acid esters that are present in foods are degraded in vivo to the animal carcinogen glycidol, which binds to the N-terminal valine of hemoglobin (Hb) to form N-(2,3-dihydroxypropyl)valine (diHOPrVal) adducts. The existence of other chemicals that are converted to glycidol is unknown. To determine the effect of different exposure conditions on the formation of diHOPrVal adducts, several glycidol-related chemicals (3-monochloropropane-1,2-diol; 3-MCPD, epichlorohydrin, glyceraldehyde, acrylic acid, and 1,2-propanediol) were evaluated using in vitro and in vivo (single/repeated dose) methods. In vitro, the reaction of 3-MCPD or epichlorohydrin with human Hb produced 17% and 0.7% of diHOPrVal, as compared to equimolar glycidol, respectively. Following a single administration of glycidol-related compounds to ICR mice, diHOPrVal formation was observed only in the epichlorohydrin-treated group after day 5 of exposure. After 14 days of repeated dosing, the amounts of diHOPrVal produced by epichlorohydrin and 3-MCPD in vivo were <1% of diHOPrVal produced by an equal molar concentration of glycidol. Furthermore, glyceraldehyde group produced 0.2% of diHOPrVal at the same molar concentration of glycidol equivalents, in which diHOPrVal formation could not be confirmed by the in vitro assay. The results indicate the usefulness of diHOPrVal as an exposure marker for glycidol; however, the contribution of its formation in vivo by exposure to various chemicals will be necessary to validate and interpret the results.

Mitigation of 3-monochloropropane 1,2 diol ester and glycidyl ester in refined oil - A review

The 3-Monochloropropane-1, 2-diol ester (3-MCPDE) and glycidyl ester (GE) are formed at high processing temperatures with the presence of respective precursors. Both are potentially harmful to humans, causing adverse health impacts including kidney damage, reproductive problems, and increased risk of cancer. The presence of 3-MCPDE and GE in palm oil is of particular concern because of its widespread use by the food industry. There are a variety of methods for reducing 3-MCPDE and GE. For example, water washing eliminates mostly inorganic chlorides that, in turn, reduce the formation of 3-MCPDE. 3-MCPDE has also been reduced by up to 99% using combinations of methods and replacing stripping steam with alcohol-based media. Activated carbon, clay, antioxidants, potassium-based salts, and other post-refining steps have positively lowered GE, ranging from 10 to 99%. Several approaches have been successful in reducing these process contaminants without affecting other quality metrics.

Multivariate modelling analysis for prediction of glycidyl esters and 3-monochloropropane-1,2-diol (3-MCPD) formation in periodically heated palm oil

Palm oil is a vegetable oil that is widely used for cooking and deep-frying because of its affordability. However, repeatedly heated palm oil is also prone to oxidation due to its significant content of unsaturated fatty acids and other chemical toxicants such as glycidyl esters and 3-monochloropropane-1,2-diol (3-MCPD). Initially, the physicochemical properties such as colour, viscosity, peroxide, p-anisidine and total oxidation (TOTOX) of periodically heated palm oil were investigated. Chemical profiling and fingerprinting of six different brands of palm cooking oil during heating cycles between 90 and 360 min were conducted using Fourier transform infrared (FTIR) and 1H Nuclear Magnetic Resonance (NMR) metabolomics. In addition, the multivariate analysis was employed to evaluate the 1H NMR spectroscopic pattern of repeatedly heated palm oil with the corresponding physicochemical properties. The FTIR metabolomics showed significant different of the chemical fingerprinting subjected to heating duration, which in agreement with the result of 1H NMR metabolomics. Partial least squares (PLS) model revealed that most of the physicochemical properties of periodically heated palm oil are positively correlated (R2 values of 0.98-0.99) to their spectroscopic pattern. Based on the findings, the color of the oils darkened with increased heating time. The peroxide value (PV), p-anisidine value (p-AnV), and total oxidation (TOTOX) values increased significantly due to degradation of unsaturated compounds and oxidation products formed. We identified targeted metabolites (probable carcinogens) such as 3-monochloropropane-1,2-diol (3-MCPD) and glycidyl ester (GE), indicating the conversion of 3-MCPD to GE in repeatedly heated oils based on PCA and OPLSDA models. Our correlation analysis of NMR and physicochemical properties has shown that the conversion of 3-MCPD to GE was significantly increased from 180 to 360 min cooking time. The combination spectroscopic techniques with physicochemical properties are a reliable and robust methods to evaluate the characteristics, stability and chemical's structure changes of periodically heated palm oil, which may contribute to probable carcinogens development. This study has proven that combination of NMR and physicochemical analysis may predict the formation of the probable carcinogens of heated cooking oil over time which emphasizing the need to avoid certain heating cycles to mitigate formation of probable carcinogens during cooking process.

The occurrence and probabilistic risk assessment of 3-MCPDEs and GEs in infant formulas from Chinese market employing Monte Carlo simulation technique

3-monochloropropane-1,2-diol esters (3-MCPDEs) and glycidyl esters (GEs) are food contaminants and have arisen continuous attention due to their toxicity, especially towards infants. Current risk assessment of these contaminants was mostly employing deterministic approaches, lacking quantitative characterization of the likelihood, incidence, or severity of the risks involved. Herein, 3-MCPDE and GE levels in 46 representative infant formulas (IFs) from Chinese market were determined by GC-MS/MS. Then, combining the occurrence data and consumption data from China National Food Consumption Survey, the Monte Carlo simulation-based probabilistic model for risk assessment of 3-MCPDEs and GEs in IFs from Chinese market was established. The results showed that all P90 (90th percentiles) hazard quotient values were below 1, demonstrating 3-MCPDEs didn't pose health risks to most populations aged 0-36 months old. However, for 0-12 months old groups, P10 (10th percentiles) margin of exposure values were all below 25000, indicating GEs may pose potential risks to 10% of this group. Uncertainty analysis revealed that the probabilistic model had considered uncertainties of model input and distribution, and realized refined assessment. This study is the first report on probabilistic assessment of 3-MCPDEs and GEs in IFs, which also provided references for the formulation of related regulatory limits in China.

Simultaneous mitigation of 3-monochloropropane 1,2 diol ester and glycidyl ester in edible oils: a review

The rising concern about the presence of 3-monochloropropane 1,2 diol ester (3-MCPDE) and glycidyl ester (GE) in food has prompted much research to be conducted. Some process modifications and the use of specific chemicals have been employed to mitigate both 3-MCPDE and GE. Alkalisation using NaOH, KOH, alkali metals or alkaline earth metals and post sparging with steam or ethanol and short path distillation have shown simultaneous mitigation of 51-91% in 3-MCPDE and of 13-99% in GE, both contaminants achieved below 1000 µg/kg. Some of the mitigation methods have resulted in undesirable deterioration in other parameters of the refined oil. When the processed oil is used in food processing, it results in changes to 3-MCPDE and GE. Repeated deep frying above 170 °C in the presence of NaCl and baking at 200 °C with flavouring (dried garlic and onion), resulted in increased 3-MCPDE. Repeated frying in the presence of antioxidants (TBHQ, rosemary and phenolics) decreased 3-MCPDE in processed food. The GE content in foods tends to decline with time, indicating instability of GE's epoxide ring.

Monoacylglycerol lipase from marine Geobacillus sp. showing lysophospholipase activity and its application in efficient soybean oil degumming

Enzymatic degumming is an essential refining process to improve oil quality. In this study, a monoacylglycerol lipase GMGL was derived from marine Geobacillus sp., and was found that not only took monoacylglycerol (MAG) as substrate, but also had activity toward lysophosphatidylcholine (LPC), lysophosphatidylethanolamine (LPE) and glycerolphosphatidylcholine (GPC). Binding free energy showed LPC and LPE could bind with enzyme stably as MAG. It presented great potential in the field of enzymatic degumming. The phosphorus content in crude soybean oil decreased from 680.50 to 2.01 mg/kg and the yield of oil reached to 98.80 % after treating with phospholipase A1 (Lecitase Ultra) combined with lipase GMGL. An ultrahigh-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) was developed to identify 21 differential phospholipids between crude soybean oil and enzymatic treatment. This work might shed some light on understanding the catalytic mechanism of monoacylglycerol lipase and provide an effective strategy for enzymatic degumming.

Development of physiologically based toxicokinetic models for 3-monochloropropane-1,2-diol and glycidol

3-Monochloropropane-1,2-diol (3-MCPD), glycidol, together with their fatty acid esters are commonly presented in various food and have shown carcinogenicity in various laboratory animals. Public health risk assessment of 3-MPCD and glycidol exposure relies on quantitative tools that represent their in vivo toxicokinetics. In order to better understand the absorption, distribution, metabolism, and excretion profiles of 3-MCPD and glycidol in male rats, a physiologically based pharmacokinetic (PBTK) model was developed. The model's predictive power was evaluated by comparing in silico simulations to in vivo time course data obtained from experimental studies. Results indicate that our PBTK model successfully captured the toxicokinetics of both free chemicals in key organs, and their metabolites in accessible biological fluids. With the validated PBTK model, we then gave an animal-free example on how to extrapolate the toxicological knowledge acquired from a single gavage to a realistic dietary intake scenario. Three biomarkers, free compound in serum, urinary metabolite DHPMA, and glycidol-hemoglobin adduct (diHOPrVal) were selected for in silico simulation following constant dietary intakes, and their internal levels were correlated with proposed external daily exposure via reverse dosimetry approaches. Taken together, our model provides a computational approach for extrapolating animal toxicokinetic experiments to biomonitoring measurement and risk assessment.

Stable Isotope Tracer to Reveal the Interconversion between 3-Monochloro-1,2-propanediol Ester and Glycidyl Ester during the Deodorization Process

In this study, the effects of the deodorization process on the interconversion between 3-monochloro-1,2-propanediol ester (3-MCPDE) and glycidyl ester (GE) using 3-MCPDE or GE standards containing deuterium-labeled palmitic acid (*P), oleic acid (*O), or linoleic acid (*L) were examined. Deuterium-labeled 3-MCPDE or GE was added to palm oil then deodorized at 250 °C for 20, 40, or 60 min. In the 3-MCPDE-spiked palm oil, the deuterium-labeled 3-MCPDE content decreased with deodorization time. Moreover, GE containing *P or *O was detected, but there was no GE containing *L in the 3-MCPDE-spiked palm oil. In the GE-spiked oil, GE containing *O or *L decreased with deodorization time, but the content of GE containing *P did not change over the time. Furthermore, deuterium-labeled 3-MCPDE was not detected in the GE-spiked oil. These results suggest that 3-MCPDE is converted into GE and that fatty acid species bound to 3-MCPDE or GE may affect their interconversion.

Pathways to Identify Electrophiles In Vivo Using Hemoglobin Adducts: Hydroxypropanoic Acid Valine Adduct and Its Possible Precursors

Analytical methods and tools for the characterization of the human exposome by untargeted mass spectrometry approaches are advancing rapidly. Adductomics methods have been developed for untargeted screening of short-lived electrophiles, in the form of adducts to proteins or DNA, in vivo. The identification of an adduct and its precursor electrophile in the blood is more complex than that of stable chemicals. The present work aims to illustrate procedures for the identification of an adduct to N-terminal valine in hemoglobin detected with adductomics, and pathways for the tracing of its precursor and possible exposure sources. Identification of the adduct proceeded via preparation and characterization of standards of adduct analytes. Possible precursor(s) and exposure sources were investigated by measurements in blood of adduct formation by precursors in vitro and adduct levels in vivo. The adduct was identified as hydroxypropanoic acid valine (HPA-Val) by verification with a synthesized reference. The HPA-Val was measured together with other adducts (from acrylamide, glycidamide, glycidol, and acrylic acid) in human blood (n = 51, schoolchildren). The HPA-Val levels ranged between 6 and 76 pmol/g hemoglobin. The analysis of reference samples from humans and rodents showed that the HPA-Val adduct was observed in all studied samples. No correlation of the HPA-Val level with the other studied adducts was observed in humans, nor was an increase in tobacco smokers observed. A small increase was observed in rodents exposed to glycidol. The formation of the HPA-Val adduct upon incubation of blood with glycidic acid (an epoxide) was shown. The relatively high adduct levels observed in vivo in relation to the measured reactivity of the epoxide, and the fact that the epoxide is not described as naturally occurring, suggest that glycidic acid is not the only precursor of the HPA-Val adduct identified in vivo. Another endogenous electrophile is suspected to contribute to the in vivo HPA-Val adduct level.

The Formation of 3-Monochloropropanediol Esters and Glycidyl Esters during Heat-Induced Processing Using an Olive-Based Edible Oil

With the prevalence of edible diacylglycerol (DAG) oil, which is beneficial to human, the generation of 3-monochloropropanediol esters (3-MCPDE) and glycidyl esters (GE) as well as the stability of physical properties during heat-induced processing still need to be explored. In this study, the experiment used olive-based edible oil with different contents of DAG (40, 60, and 80%) to make crackers and fry chicken. They were heated at 160 and 180 °C to determine the changes in 3-MCPDE and GE, the crackers’ hardness and gumminess, and the physical properties of the oil. During baking and frying, 3-MCPDE decreased, while the content of GE slightly increased with the prolonged heating duration. Finally, 3-MCPDE and GE were lower than 1.25 mg/kg and 1.00 mg/kg, respectively. The AV increased proportionally as duration increased and POV was below 0.30 g/100 g. In general, the changes in 3-MCPDE and GE were related to the heating temperature and duration, and not significantly (p > 0.05) related to the content of DAG.

The digestion of diacylglycerol isomers by gastric and pancreatic lipases and its impact on the metabolic pathways for TAG re-synthesis in enterocytes

The specific activities of gastric and pancreatic lipases were measured using triacylglycerols (TAG) from rapeseed oil, purified 1,3-sn-DAG and 1,2(2,3)-sn-DAG produced from this oil, as well as a rapeseed oil enriched with 40% w/w DAG (DAGOIL). Gastric lipase was more active on 1,3-sn-DAG than on 1,2(2,3)-sn-DAG and TAG, whereas pancreatic lipase displayed a reverse selectivity with a higher activity on TAG than on DAG taken as initial substrates. However, in both cases, the highest activities were displayed on DAGOIL. These findings show that DAG mixed with TAG, such as in the course of digestion, is a better substrate for lipases than TAG. The same rapeseed oil acylglycerols were used to investigate intestinal fat absorption in rats with mesenteric lymph duct cannulation. The levels of TAG synthesized in the intestine and total fatty acid concentration in lymph were not different when the rats were fed identical amounts of rapeseed oil TAG, 1,2(2,3)-sn-DAG, 1,3-sn-DAG or DAGOIL. Since the lipolysis of 1,3-sn-DAG by digestive lipases leads to glycerol and not 2-sn-monoacylglycerol (2-sn-MAG) like TAG lipolysis, these results suggest that the re-synthesis of TAG in the enterocytes can entirely occur through the "glycerol-3-phosphate (G3P)" pathway, with the same efficiency as the 2-sn-MAG pathway predominantly involved in the intestinal fat absorption. These findings shed new light on the role played by DAG as intermediate lipolysis products. Depending on their structure, 1,2(2,3)-sn-DAG versus 1,3-sn-DAG, DAG may control the pathway (2-sn-MAG or G3P) by which TAG are re-synthesized in the enterocytes.

Analysis of MCPD and Glycidyl Fatty Acid Esters in Refined Plant Oils by Supercritical Fluid Chromatography– High-Resolution Mass Spectrometry

2- and 3-chloropropane-1,2-diol (2- and 3-MCPD) and their fatty acid esters (2- and 3-MCPDEs) together with glycidyl fatty acids esters (GEs) belong to a group of process-induced contaminants. They are formed in high temperature environments and most commonly occur in refined vegetable oils. Since 2021, maximum limits for GEs and 3-MCPDEs have been enforceable in the EU, and the requirement for adequate analytical methods is constantly increasing. The aim of this study was to develop an efficient method to enable a rapid determination of nine 3-MCPDEs and seven GEs in vegetable oils within a single run employing supercritical fluid chromatography coupled to high-resolution tandem mass spectrometry (SFC–HRMS/MS). Contrary to a routine gas chromatography mass spectrometry method aimed at determination of the total MCPD pool, the sample throughput when using SFC–HRMS/MS was greatly increased, as the “dilute-and shoot” approach did not require any hydrolysis and derivatization. Additionally, the pattern of natural MCPDEs was characterized. The performance characteristics of this new method met the criteria required by Commision Regulation 2019/2093 for all target analytes.

Application of MOFs and natural clays for removal of MCPD and GEs from edible oils

The aim of this study was to investigate the removal of 3-monochloropropane-1,2-diol (3-MCPD) and glycidyl esters (GEs) from edible oils by using Metal Organic Frameworks (MOF) and natural clays. First, the model oil was treated with adsorbents and titanium (IV) butoxide-terephthalate MOF (Ti-MOF) and kaolin were selected as the best performing MOF along with natural clay, respectively, for the removal of 3-MCPD and GEs. The effects of treatment conditions were also investigated, 6.0% adsorbent level, 120 min treatment time and 95 ºC temperature were determined to be the best treatment parameters. Finally, palm oil samples were treated with Ti-MOF and kaolin under the selected conditions and removal of 3-MCPD and GEs was obtained at up to 27% and 58%, respectively. In conclusion, MOFs and natural clays showed good potential for the removal of 3-MCPD and GEs, and the efficiency of the treatment can be improved by modifying the adsorbents.

Effects of Deodorization on the Formation of Processing Contaminants and Chemical Quality of Sunflower Oil

Tocopherols and phytosterols are generally considered to be nutritionally beneficial, and 3-Monochloropropane-1,2-diol esters (3-MCPD esters), glycidyl esters (GEs) and trans fatty acids (TFAs) are generally considered to be harmful. The high temperature deodorization step is when these harmful 3-MCPD esters, GEs and TFAs are generated. Knowing how deodorization conditions affect levels of these substances is essential for designing refining processes that will produce nutritious, high quality edible oils. This study analyzed the changes of these components of sunflower oil at different temperatures (210, 230, 250 and 270°C) and times (60, 80, 100 and 120 min) during deodorization. Our research found that during the whole deodorization process (including undeodorized sunflower oil), the contents of 3-MCPD esters, GEs and TFAs all progressively increased, from 0.47 to 11.18 mg/kg, 0.24 to 18.42 mg/kg and 0.062% to 0.698%, respectively. However, the deodorization process significantly decreased the levels of tocopherols (from 535.94 to 240.26 mg/kg) and phytosterols (from 2803.58 to 1864.34 mg/kg). Meanwhile, the retention ratios of total tocopherols and total phytosterols also decreased from 96.29% to 44.83% and 92.29% to 66.50%, respectively.

Associations of 3-monochloropropane-1,2-diol and glycidol with prevalence of metabolic syndrome: Findings from Lanxi Nutrition and Safety Study

In this study, we investigated the association of 2,3-dihydroxypropyl mercapturic acid (DHPMA), a urinary biomarker of environmental and dietary exposure to 3-monochloropropane-1,2-diol and glycidol, with prevalent MetS in a Chinese middle-aged and elderly population. The urinary DHPMA concentrations were determined by ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) analysis and further calibrated by the urinary creatinine content. MetS cases were defined by the Adult Treatment Panel III criteria for Asian-Americans of National Cholesterol Education Program (NCEP/ATPIII). Multivariate-adjusted modified Poisson regression models were used to analyze the associations between the urinary DHPMA concentrations and MetS prevalence. Of the 1613 participants aged 45-75 years, we documented 552 (34.2%) MetS cases. After adjustment for potential risk factors, the relative risks (95% confidence intervals) of MetS prevalence across the increasing quartiles of DHPMA concentrations were 1.14 (0.93-1.39), 1.29 (1.06-1.56), and 1.50 (1.25-1.80), respectively, compared with the lowest quartile. We also observed strong positive association between urinary DHPMA concentrations and hypertriglyceridemia prevalence (P < 0.001 for trend). These positive associations remained unchanged in the subgroups stratified by general demographic, dietary and behavioral risk factors. These results suggested that urinary DHPMA was associated with higher prevalence of MetS among Chinese elderly people.

The role of endogenous versus exogenous sources in the exposome of putative genotoxins and consequences for risk assessment

The "totality" of the human exposure is conceived to encompass life-associated endogenous and exogenous aggregate exposures. Process-related contaminants (PRCs) are not only formed in foods by heat processing, but also occur endogenously in the organism as physiological components of energy metabolism, potentially also generated by the human microbiome. To arrive at a comprehensive risk assessment, it is necessary to understand the contribution of in vivo background occurrence as compared to the ingestion from exogenous sources. Hence, this review provides an overview of the knowledge on the contribution of endogenous exposure to the overall exposure to putative genotoxic food contaminants, namely ethanol, acetaldehyde, formaldehyde, acrylamide, acrolein, α,β-unsaturated alkenals, glycation compounds, N-nitroso compounds, ethylene oxide, furans, 2- and 3-MCPD, and glycidyl esters. The evidence discussed herein allows to conclude that endogenous formation of some contaminants appears to contribute substantially to the exposome. This is of critical importance for risk assessment in the cases where endogenous exposure is suspected to outweigh the exogenous one (e.g. formaldehyde and acrolein).

Refining Vegetable Oils: Chemical and Physical Refining

This review presents recent technologies involved in vegetable oil refining as well as quality attributes of crude oils obtained by mechanical and solvent extraction. Usually, apart from virgin oils, crude oils cannot be consumed directly or incorporated into various food applications without technological treatments (refining). Indeed, crude oils like soybean, rapeseed, palm, corn, and sunflower oils must be purified or refined before consumption. The objective of such treatments (chemical and physical refining) is to get a better quality, a more acceptable aspect (limpidity), a lighter odor and color, longer stability, and good safety through the elimination of pollutants while minimizing oil loss during processing. However, the problem is that refining removes some essential nutrients and often generates other undesirable compounds such as 3-MCPD-esters and trans-fatty acids. These compounds directly influence the safety level of refined oil. Advantages and drawbacks of both chemical and physical refining were discussed in the light of recent literature. Physical refining has several advantages over chemical one.

Palm Oil Processing and Controversies over Its Health Effect: Overview of Positive and Negative Consequences

Palm oil is the world's most commonly used vegetable oil and extracted both from fruit and seed of palm tree. However, its high saturated fatty acid content raised controversies over consumption of the oil. Few scientific findings suggest it as a risk factor for cardiovascular disease and increased consumer's awareness over healthy diet raised claim over it. So that, this article aimed to review literatures on palm oil extraction process and its positive and negative health consequences and besides suggest strategies for healthy diet. Literature search of relevant articles was conducted by using Google scholar, PubMed, Web of science, MEDLINE, World Health Organization library online catalogue, UNICEF library, Open access thesis and dissertations published between 2009 and 2021 explored. Study reports recommend that palmitic acid from vegetable source has less effect on blood total cholesterol and low density lipoprotein cholesterol level as compared to palmitic acid from animal source. In contrary tocotrienols of palm oil lowers blood bad cholesterol level by 7-38%. Moreover, palm oil triacylglycerol arrangement does not have a cardiovascular risk and evidences from available in vitro and in vivo studies are not sufficient enough to conclude palm oil as a causative agent for cardiovascular disease. For healthy diet consumers should avoid trans fatty acids, solid and semi solid oils. Finally, further studies recommended on mitigation strategies to minimize process induced toxicants of palm oil to acceptable level.

Dietary advanced glycation end-products, 2-monochloropropane-1,3-diol esters and 3-monochloropropane-1,2-diol esters and glycidyl esters in infant formulas: Occurrence, formulation and processing effects, mitigation strategies

Infant formula contains thermal processing contaminants, such as dietary advanced glycation end-products (dAGEs), glycidyl esters (GEs), 2-monochloropropane-1,3-diol esters and 3-monochloropropane-1,2-diol esters (MCPDEs). This systematic review aimed to gain insights into the occurrence of these contaminants in different types of infant formula, to understand potential effects of the formulation and processing of infant formulas on these contaminants, as well as into possible mitigation strategies. The occurrence of dAGEs in infant formula depends on the recipes and processing conditions. Hydrolyzed protein formulations promote dAGEs formation in infant formula since peptides are more prone to glycation than intact proteins, which is reflected in high dAGEs concentration in hypoallergenic infant formula. Different carbohydrates in recipes result into different glycation extents of infant formula: maltodextrin containing formulas contained less dAGEs than those with lactose. Concerning mitigation strategies, applying ultra-high-temperature (UHT) treatment during milk processing leads to less dAGEs formation than using in-bottle sterilization. Although data are limited, evidence showed that encapsulation of raw ingredients or the use of antioxidants or enzymes in recipes is promising. The occurrence of MCPDEs and GEs in infant formula fully depends on the vegetable oils used in the recipe. High levels of these contaminants can be found when relatively high amounts of palm oils or fats are used. The mitigation of MCPDEs and GEs should therefore be performed on fats and oils before their application to infant formula recipes. Data and knowledge gaps identified in this review can be useful to guide future studies.

Effects of Food Types, Frying Frequency, and Frying Temperature on 3-Monochloropropane-1,2-diol Esters and Glycidyl Esters Content in Palm Oil during Frying

3-Monochloropropanediol esters (3-MCPDE) and glycidyl esters (GE) have high toxicity and have drawn global attention because of their widespread occurrence in refined oils and oil-based foods. In this study, the effects of food type (potato chips and chicken breasts), frying frequency, and frying temperature on the formation of 3-MCPDE and GE in palm oil (PO) were investigated. The results showed that 3-MCPDE was formed easier in chicken breasts than potato chips. The GE content decreased in PO after it was used for frying potato chips and chicken breasts with or without NaCl. Frying frequency was an influencing factor in the formation of 3-MCPDE and the decrease in GE in PO. Frying temperature was positively correlated with GE degradation, while it had a bidirectional effect on the formation of 3-MCPDE. The formation kinetic equations indicated that 3-MCPDE and GE followed zero-order reactions in PO. The estimated activation energy (Ea) of 1,2-bis-palmitoyl-3-chloropropanediol (Pa-Pa, 41.05 kJ/mol) was lower than those of the other three types of 3-MCPDE; this is the first theoretical explanation for why PO contains more 3-MCPD than other edible oils. Among GEs, glycidyl oleate (Li-GE) was degraded more readily than other GEs.

The inhibitory effects of sesamol and sesamolin on the glycidyl esters formation during deodorization of vegetables oils

BACKGROUND

Glycidyl esters (GEs) have attracted worldwide attention for their potential harm to human health. The GEs in edible oils mainly form during the deodorization of the oil refining processes. We used sesamol and sesamolin to inhibit the formation of GEs in model corn oil (MCO), model palm oil (MPO) and model rice bran oil (MRO) during a deodorization process.

RESULTS

The results showed that, in the three model oils, the total GE content was in the following order from highest to lowest: MRO (1437.98 μg kg^-1 ) > MPO (388.64 μg kg^-1 ) > MCO (314.81 μg kg^-1 ). The inhibitory effect of the three antioxidants on the formation of GEs in the MCO was in the following order from strongest to weakest: tert-butylhydroquinone (TBHQ) > sesamol > sesamolin.

CONCLUSION

When the mass percentage of sesamol was 0.05%, its inhibition percentage on GEs was close to the inhibition percentage of 0.02% added TBHQ. The present study provides a foundation for understanding how to inhibit the formation of GEs in oils by adding sesamol during the deodorization process.

Occurrence of thermally induced glycidyl esters and 3-monochloropropane-1,2-diol esters in refined oils and pressed oils manufactured by different processes and associated with human health risks in Taiwan

Glycidyl esters (GEs) and 3-monochloropropane-1,2-diol esters (3-MCPDEs) are heat-induced contaminants mainly formed during oil refining. Information on the occurrence of these contaminants in pressed oils is still limited. In this study, 16 oilseeds pressed with a screw press and a hydraulic press had extremely low concentrations of GEs and 3-MCPDEs. Seed-roasting at high temperatures was the principal factor that significantly increased contents of GEs and 3-MCPDEs in pressed oils, in which higher precursor levels were observed. Occurrence data of GE and 3-MCPDE concentrations in refined oils (n = 25) and pressed oils (n = 26) marketed in Taiwan showed that hot-pressed oils had higher concentrations than their cold-pressed counterparts, and average concentrations of refined oils were > 10-fold higher than those of pressed oils. Risk assessment using the margin of exposure (MOE) approach indicated the presence of GEs in edible oils was of concern for food safety, especially for people who frequently use refined oils.