Direct Determination of MCPD Fatty Acid Esters and Glycidyl Fatty Acid Esters in Vegetable Oils by LC-TOFMS

Risk assessment of 3-MCPD esters and glycidyl esters from the formulas for infants and young children up to 36 months of age

Esters of 2-monochloropropane-1,2-diol (2-MCPD), 3- monochloropropane-1,2-diol (3-MCPD), and glycidol are present in infant formulas, follow-on foods and similar compositions. They arise mainly from the vegetable oil content and may cause harmful effects in consumers. The contents of these substances in formulas were determined indirectly by converting the esters to the free form, followed by derivatization and analysis by gas chromatography-tandem mass spectrometry (GC-MS/MS). The validation results demonstrate that the method had sufficient specificity and adequate accuracy. The limits of detection (LOD) and limits of quantification (LOQ) for each of 2-MCPDE, 3-MCPDE, and GE were 1.5 and 5 µg/kg, respectively. Formula intake by children up to 36 months of age was surveyed, and the data was used to assess the risks due to 3-MCPD esters (3-MCPDE) and glycidyl esters (GE). The mean exposure dose of 3-MCPDE for different age groups ranged from 0.51 to 1.13 µg/kg bw per day. The corresponding mean GE exposure ranged from 0.031 to 0.069 µg/kg bw per day. Neither mean values nor the percentile 95% values of 3-MCPDE exposure doses exceed the recommended provisional maximum tolerable daily intake (PMTDI).

Occurrence and risk assessment of 3-monochloropropanediols esters (3-MCPDE), 2-monochloropropanediol esters (2-MCPDE), and glycidyl esters (GE) in commercial infant formula samples from Malaysia

The presence of 3-monochloropropanediol esters (3-MCPDE), 2-monochloropropanediol esters (2-MCPDE) and glycidyl esters (GE) in infant formula products has raised serious concerns. They incorporate vegetable oils, particularly palm-based oils, which are well-known to contain large amounts of these process contaminants. An analysis was conducted on infant formula samples (n = 16) obtained from the Malaysian market to determine the levels of 3-MCPDE, 2-MCPDE and GE using gas chromatography-mass spectrometry (GC-MS). The method was validated, with a limit of quantification (LOQ) on instrument of 0.10 µg/g for all analytes. The median concentrations of 3-MCPDE, 2-MCPDE and GE in infant formula in this study were 0.008 µg/g, 0.003 µg/g and 0.002 µg/g respectively. The estimated dietary intakes calculated from consumption of infant formula show higher exposures to infants within the age group of 0 to 5 months, highest for GE (1.61 µg/kg bw/day), followed by 3-MCPDE (0.68 µg/kg bw/day) and 2-MCPDE (0.41 µg/kg bw/day) compared to the age group of 6 to 12 months. Only one sample, relating to GE exposure is a potential risk for both age groups with MOE value below 25,000.

Occurrence of glycidyl esters in infant formula products on the Canadian market between 2015 and 2019

Glycidyl fatty acid esters (GEs) are processing contaminants formed during refining steps of vegetable oils. 'In vivo' hydrolysis of GEs releases potentially carcinogenic and genotoxic glycidol (2,3-epoxy-1-propanol). Occurrence of GEs in vegetable oils used for infant formula manufacturing may pose a potential health concern for formula-fed infants. Refined oils are commonly used as the main fat ingredient in formula manufacturing. For this study, different infant formula products (powders, concentrates and ready-to-feed formula products) were purchased and analysed in 2015 (35 samples) and 2019 (33 samples). Seven individual GEs were analysed by LC-MS/MS via direct approach by stable isotope dilution analysis, and total bound glycidol concentrations were calculated. Concentrations of bound glycidol in reconstituted formula reached maxima of 40.3 ng/g in the 2015 samples and 31.5 ng/g in the samples collected in 2019, with respective means of 8.7 ng/g and 6.7 ng/g. The analysed bound glycidol concentrations are comparable with concentration ranges from other studies, but are higher than observed in studies from the European market. Temporal trend data show a reduction of bound glycidol concentrations in 2019. GE concentrations were compared across different manufacturers.

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.

Methods, principles, challenges, and perspectives of determining chloropropanols and their esters

Chloropropanols and their esters are a group of food contaminants that have various toxicities to the human body. Research and control to chloropropanols and their esters is important to food safety. Therefore, the sensitive, accurate, precise, and effective determination of chloropropanols and their esters is highly essential to study their concentration, formation, and mitigation. The indirect method, commonly applied in the determination of chloropropanols and their esters, is based on the cleavage of ester bond, extraction, and derivatization. The conventional indirect method will still be the mostly used method in the near future due to its good sensitivity and feasibility, although its parameters need to be chosen and optimized according to sample stuffs and chloropropanol concentrations. Meanwhile, direct method and other quantitative methods should also be developed for special applications, such as studying the profile of chloropropanol esters and rapid screening protocol. The challenges and future perspectives of these methods are discussed in this review. This review can provide a reference on the selection, designation, and modification of methods for determining chloropropanols and their esters.

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.

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).

Simultaneous determination of monochloropropanediol esters and glycidyl esters in vegetable oils by acidic transesterification-gas chromatography-mass spectrometry

建立了一种气相色谱-质谱同时测定植物油中3-氯丙二醇酯、2-氯丙二醇酯和缩水甘油酯的方法。称取0.25 g样品,依次加入内标工作液、四氢呋喃和酸性溴化钠溶液,50 ℃水浴反应15 min,加入6 g/L碳酸氢钠溶液终止反应,使用正己烷提取,上层液经氮气吹干后用四氢呋喃溶解。随后加入1.8%(v/v)硫酸-甲醇溶液于40 ℃恒温水浴中反应16 h,加入饱和碳酸氢钠溶液终止反应。样液再经过净化、衍生、提取、氮吹后,以1 mL正己烷定容,过膜,进样测定。采用毛细管气相色谱柱DB-5MS(30 m×0.25 mm×1 μm)分离,程序升温,电子轰击电离(EI)源检测,在选择离子扫描模式下,以保留时间和特征离子信息进行定性分析,内标法定量。结果表明,3-氯丙二醇酯、2-氯丙二醇酯和缩水甘油酯在0.01~0.80 mg/L范围内线性关系良好,相关系数(r²)均在0.999以上,方法的检出限(S/N=3)和定量限(S/N=10)分别为25、25、20 μg/kg和75、75、60 μg/kg。选取4种不同基质类型的样品,在低、中、高3个不同添加水平下的平均回收率为89.0%~98.7%,相对标准偏差(RSD)在2.05%~7.81%之间。采用该方法测定了市售112份植物油样本,其中有84份样本检出3-氯丙二醇酯、2-氯丙二醇酯和缩水甘油酯。与已建立的国家标准方法(GB 5009.191-2016)和行业标准方法(SN/T 5220-2019)相比,该方法所采用的酸性酯交换法可避免副反应(碱性条件下3-氯丙二醇、2-氯丙二醇及3-溴丙二醇向游离态缩水甘油转化)的发生,同时该方法也弥补了国家标准和行业标准无法对3-氯丙二醇酯、2-氯丙二醇酯和缩水甘油酯同时进行测定的缺失。该方法实验操作更高效,结果更准确、重复性更好,对我国植物油中3-氯丙二醇酯、2-氯丙二醇酯和缩水甘油酯污染水平的控制、检测标准的制定和生产工艺的优化具有一定的理论和现实意义。

Non-Target Detection of Diversity of Volatile Chlorine Compounds in Frying Oil and Study on the Influencing Factors of Their Formation

Headspace-gas-chromatography ion-mobility spectrometry (HS-GC-IMS) proved the diversity of volatile chlorinated compounds (VCCs) in frying oil in this work. First, the VCCs were obtained by headspace by heating the frying oil at 80 °C for 30 min. Then, those compounds were separated by GC capillary column in the first dimension and by IMS in the second dimension, respectively. And at last, those compounds were detected in negative ion mode for non-targeting. The study results indicated that VCCs' formation depends on the contents of NaCl and water, heating temperature and time, and the types of oil. The refining process does not affect the detection of VCCs, indicating the durability of such targets as indicators for assessing deep-frying oil. Using HS-GC-IMS, the VCCs were detected to evaluate 16 authentic refined deep-frying oils from the market with an accuracy of 100%.

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.

A summary of 2-, 3-MCPD esters and glycidyl ester occurrence during frying and baking processes

Monochloropropanediol (MCPD) esters and glycidyl esters (GE) are the process contaminants found in frying and baking, except the refining process. The free form MCPD and glycidol are released from their parent esters via lipase hydrolysis while they are carcinogen and genotoxic carcinogen, respectively. MCPD esters and GE are formed endogenously during vegetable oil refining process. Then, their concentration were experimented during subsequent food processing methods, especially frying and baking. This review discussed the occurrence of 2-, 3-MCPD esters and GE during frying and baking processes. Process temperature, process duration, presence of precursors, and their combined effects are highly related to MCPD esters and GE formations. An elevated temperature and processing time can increase the formation of these contaminants until an optimum rate and then followed by the decomposition. Also, other factors such as the presence of chloride ions, moisture, and partial acylglycerol can further facilitate MCPD esters and/or GE formation.

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Frying and baking trigger formation of MCPD esters and GE.

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MCPD esters and GE are formed endogenously during refining process.

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The concentration of MCPD esters and GE elevated during thermal processing.

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Temperature, process duration, and precursors cause MCPD esters and GE formations.

Occurrence of 3-monochloropropane-1,2-diol (3-MCPD) esters and glycidyl esters in infant formulas from Germany

Fatty acid esters of 3-monochloropropane-1,2-diol (3-MCPD), 2-monochloropropanediol-1,3-diol (2-MCPD), and glycidol are heat-induced processing contaminants formed during the deodorisation step of edible oil refining. Because these compounds are potentially carcinogenic and/or genotoxic, their presence in refined oils and fats and foods containing these oils/fats poses possible health concerns. In particular, formula-fed infants may be exposed to these compounds due to their presence in commercial infant formulas. For this reason, in 2018, the European Union established maximum limits for glycidyl esters in oils/fats and infant formulas and recently, as of January 2021, implemented regulations for the sum of free 3-MCPD and 3-MCPD fatty acid esters as well. This work involved the analysis of 3-MCPD and glycidyl ester contents in 45 infant formula products purchased from German supermarkets in 2019. The data produced in this study showed that average contaminant concentrations across all manufacturers were exceptionally low, with 100% of the products analysed falling below the current EU regulation for glycidyl esters in powdered formulas and 96% of the products analysed meeting the recently implemented regulation for the sum of free and bound 3-MCPD. In addition, a comparison of the 2019 data set to occurrence data collected for German formulas purchased in 2015 showed that average bound 3-MCPD and glycidol concentrations have decreased (from 0.094 to 0.054 µg g^-1 and from 0.010 to 0.006 µg g^-1, respectively), likely indicating that additional/improved mitigation measures for reducing contaminant concentrations in infant formulas have been implemented over the 4-year period. The data collected in this occurrence study are suitable for estimating levels of exposure to these compounds for German infants.Abbreviations: 2-MCPD: 2-monochloropropane-1,3-diol; 3-MCPD: 3-monochloropropane-1,2-diol; ARA: arachidonic acid; CE: collision energy; CXP: collision cell exit potential; DHA: docosahexaenoic acid; DP: declustering potential; EP: entrance potential; EPA: eicosapentaenoic acid; EtOAc: ethyl acetate; IPA: isopropanol; LC-MS/MS: liquid chromatography-tandem mass spectrometry; MeOH: methanol; MTBE: methyl tert-butyl ether; SPE: solid-phase extraction.

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.

First Determination of Glycidyl Ester Species in Edible Oils by Reverse-Phase Ultra-Performance Liquid Chromatography Coupled with an Evaporative Light-Scattering Detector

In this work, a new ultra-performance liquid chromatograph-evaporative light-scattering detector (UPLC-ELSD) method for quantitation of glycidyl esters (GE) contents in edible oils is presented. The method features complete separation of five GE species within 20 min by a C18 column and gradient elution with a mobile phase consisting of 85% and 2.5% methanol aqueous solutions. The coefficients of regression (R²) were all ≥0.9999 for the linear-quadratic regression curves of GE species in a concentration range of 5~80 μg/mL. The intraday and interday recoveries (%) of GE species in solvent were in a range of 81.3~107.3%, and the intraday and interday coefficients of variation (CVs, %) were all ≤8.6%. The average recovery (%) of GE species spiked in extra-virgin olive oil samples ranged from 88.3~107.8% and the intermediate precision (CV, %) of ≤14% indicated acceptable accuracy and precision. The method exhibited limit of quantification (LOQ) for each GE species (0.6 μg glycidol equivalents/g oil). The method was applied to determine GE concentrations of six commercial oil samples, and total glycidol equivalents were consistent with data obtained by GC-MS method. This UPLC-ELSD method could be adopted for precursory screening and research purposes to improve food safety when MS detectors are unavailable.

Determination of glycidyl esters and 3-MCPD esters in edible oils by sample pretreatment with the combination of lipase hydrolysis and modified QuEChERS for GC-MS analysis

Glycidyl esters (GEs) and 3-chloroprapane-1,2-diol esters (3-MCPDEs) are processing contaminants in refined edible oils that have raised concerns globally owing to their potentially carcinogenic properties. Official analytical methods for GEs and 3-MCPDEs, such as AOCS Cd 29a-13 and AOCS Cd 29b-13, require up to 16 h for chemical hydrolysis. Also, parallel experiments should be conducted to correct for the conversion of analytes during hydrolysis in AOCS Cd 29b-13. For AOCS Cd 29c-13 with the shortest operating time, the reaction time (3.5-5.5 min) and temperature of alkaline hydrolysis should be carefully controlled, implying the accuracy may be influenced by human errors. Here, we propose a novel method based on Candida rugosa lipase hydrolysis and direct detection of free form GEs, glycidol, which was achieved by sample preparation with modified QuEChERS, to prevent side reactions in previous approaches, and also to shorten the overall sample preparation time. Glycidol was directly analyzed without halogenation and derivatization, whereas 3-MCPD required derivatization for analysis by GC-MS. Our method showed good accuracy and precision in terms of repeatability, intermediate precision, and reproducibility (inter-laboratory precision). The limit of detection (LOD) and limit of quantification (LOQ) for glycidol were 0.02 and 0.1 mg/kg, which is sufficient for practical applications. The proposed method was further compared with AOCS Cd 29c-13 by determination of GEs content in commercial oil samples and spiked samples. Our method with a streamlined procedure seems to possess potential advantage of reduced errors from operational factors. This proposed method based on direct detection of glycidol may serve as a simplified alternative for routine analysis of GEs and 3-MCPDEs in edible oils.

In-house validation of accelerated solvent extraction-gas chromatography-mass spectrometry for the determination of bound 3- and 2-monochloropropanediols (MCPD) and glycidol in food products

The study aimed to establish the detection method for bound 3-, 2-MCPD, and glycidol using accelerated solvent extraction (ASE) and gas chromatography mass spectrometry (GC-MS). The ASE was modified for reduced solvent volume and process time to extract lipid from the chocolate spread, infant formula, potato chips, and sweetened creamer. The solvent selected for ASE was a mixture of iso-hexane and acetone at 100°C with the lipid and analyte recovery ranging from 96.9% to 98.6% and 84.1% to 107.5%, respectively. The derivatisation of analytes was adopted from the AOCS method Cd29a-13 for GC-MS analysis. The results showed that the coefficient of determination (R²) of all analytes was >0.99. The limit of detection (LOD) was 0.1 mg kg^-1 expressed in lipid basis for both bound 3- and 2-MCPD and 0.2 mg kg^-1 expressed in lipid basis for bound glycidol. The limit of quantitation (LOQ) was 0.3 mg kg^-1 expressed in lipid basis for both bound 3- and 2-MCPD and 0.6 mg kg^-1 expressed in lipid basis for bound glycidol. A blank spiked with 3-monochloropropanediols fatty acid esters (MCPDE) and 2-MCPDE (0.3, 2.1, and 7.2 mg kg^-1) and glycidol esters (0.6, 4.7, and 16.6 mg kg^-1) were chosen for accuracy and precision tests. The recoveries were 91.7% to 105.9%. Both repeatability and within-laboratory reproducibility of the analysis were within the acceptable level of precision ranging from 1.7% to 16%. This is the first time that a full validation procedure extending to both accuracy and precision tests has been carried out for sweetened creamer and chocolate spread. Overall, the combined protocol of ASE and AOCS Cd29a-13 was successfully validated for both solid and liquid food samples with lipid content from 10% to 30%.

A Revisit to the Formation and Mitigation of 3-Chloropropane-1,2-Diol in Palm Oil Production

Process-based contaminants in food—particularly in vegetable oils—have been a topic of interest due to their potential health risk on humans. Oral consumption above the tolerable daily intake might result in health risks. Therefore, it is critical to correctly address the food contaminant issues with a proper mitigation plan, in order to reduce and subsequently remove the occurrence of the contaminant. 3-monochloropropane-1,3-diol (3-MCPD), an organic chemical compound, is one of the heat- and process-induced food contaminants, belonging to a group called chloropropanols. This review paper discusses the occurrence of the 3-MCPD food contaminant in different types of vegetable oils, possible 3-MCPD formation routes, and also methods of reduction or removal of 3-MCPD in its free and bound esterified forms in vegetable oils, mostly in palm oil due to its highest 3-MCPD content.

Monitoring of heat-induced carcinogenic compounds (3-monochloropropane-1,2-diol esters and glycidyl esters) in fries

3-Monochloropropane-1,2-diol (3-MCPD) esters and glycidyl esters (GE) are heat-induced contaminants which form during oil refining process, particularly at the high temperature deodorization stage. It is worth to investigate the content of 3-MCPD and GE in fries which also involved high temperature. The content of 3-MCPD esters and GE were monitored in fries. The factors that been chosen were temperature and duration of frying, and different concentration of salt (NaCl). The results in our study showed that the effect was in the order of concentration of sodium chloride < frying duration < frying temperature. The content of 3-MCPD esters was significantly increased whereas GE was significantly decreased, when prolong the frying duration. A high temperature results in a high 3-MCPD ester level but a low GE level in fries. The present of salt had contributed significant influence to the generation of 3-MCPD. The soaking of potato chips in salt showed no significant effect on the level of GE during the frying. The oil oxidation tests showed that all the fries were below the safety limit. Hence, the frying cycle, temperature and the added salt to carbohydrate-based food during frying should be monitored.

Mass Spectrometry for Analysis of Changes during Food Storage and Processing

Many physicochemical changes occur during food storage and processing, such as rancidity, hydrolysis, oxidation, and aging, which may alter the taste, flavor, and texture of food products and pose risks to public health. Analysis of these changes has become of great interest to many researchers. Mass spectrometry is a promising technique for the study of food and nutrition domains as a result of its excellent ability in molecular profiling, food authentication, and marker detection. In this review, we summarized recent advances in mass spectrometry techniques and their applications in food storage and processing. Furthermore, current technical challenges associated with these methodologies were discussed.

Contamination of some foodstuffs marketed in Italy by fatty acid esters of monochloropropanediols and glycidol

Fatty acid esters of 3-monochloropropanediol (3-MCPD), 2-MCPD and glycidol (Gly) are food-processing contaminants that cause concerns about possible adverse health effects. The present study evaluates the contamination levels of the three ester classes in 130 samples of foodstuffs marketed in Italy covering 10 food categories, namely margarines, oils, roasted coffee, breakfast cereals, salted crackers, cookies, infant biscuits, rusks, breads and potato crisps. The analytical method employed is a so-called indirect method that entails MCPD/glycidol cleavage from their esterified forms, cleanup, derivatisation and GC-MS analysis. The MCPDs and glycidol concentrations (from esters) were found to be equal or a little higher than the levels reported in previous studies conducted in other European countries and described in the literature. 3-MCPD was the predominant compound in all foodstuffs analysed with the exception for rusks where Gly levels were slightly higher. Considering the sum of MCPD and Gly esters, the most contaminated foodstuffs were seed oils, followed by margarines and cookies, whereas roasted coffee, bread, rusks, cornflakes and infant biscuits were less contaminated with MCPDs and Gly concentrations often below LOQ or LOD values. Refined olive oil, potato chips and salted crackers showed contamination levels intermediate between the two above groups. The results of this study also confirm that the use of palm oil as an ingredient or frying medium is an important cause of increase of the levels of MCPD and Gly esters, especially in salted crackers, rusks and potato crisps. Finally, the Italian intake of 3-MCPD due to the various foods analysed has been calculated and related to TDI. The MoE for Gly was also estimated.

Rapid assessment of total MCPD esters in palm-based cooking oil using ATR-FTIR application and chemometric analysis

The technique of Fourier transform infrared spectroscopy is widely used to generate spectral data for use in the detection of food contaminants. Monochloropropanediol (MCPD) is a refining process-induced contaminant that is found in palm-based fats and oils. In this study, a chemometric approach was used to evaluate the relationship between the FTIR spectra and the total MCPD content of a palm-based cooking oil. A total of 156 samples were used to develop partial least squares regression (PLSR), artificial neural network (nnet), average artificial neural network (avNNET), random forest (RF) and cubist models. In addition, a consensus approach was used to generate fusion result consisted from all the model mentioned above. All the models were evaluated based on validation performed using training and testing datasets. In addition, the box plot of coefficient of determination (R²), root mean square error (RMSE), slopes and intercepts by 100 times randomization was also compared. Evaluation of performance based on the testing R² and RMSE suggested that the cubist model predicted total MCPD content with the highest accuracy, followed by the RF, avNNET, nnet and PLSR models. The overfitting tendency was assessed based on differences in R² and RMSE in the training and testing calibrations. The observations showed that the cubist and avNNET models possessed a certain degree of overfitting. However, the accuracy of these models in predicting the total MCPD content was high. Results of the consensus model showed that it slightly improved the accuracy of prediction as well as significantly reduced its uncertainty. The important variables derived from the cubist and RF models suggested that the wavenumbers corresponding to the MCPDs originated from the -CH=CH₂ or CH=CH (990-900 cm^-1) and C-Cl stretch (800-700 cm^-1) regions of the FTIR spectrum data. In short, chemometrics in combination with FTIR analysis especially for the consensus model represent a potential and flexible technique for estimating the total MCPD content of refined vegetable oils.

Fatty Acid Esters of 3-Monochloropropanediol: A Review

Fatty acid esters of 3-monochloropropane-1,2-diol (3-MCPD esters) are a new group of processing-induced chemical toxicants with possible nephrotoxicity and testicular toxicity. 3-MCPD esters have been detected in many food categories, including refined edible oils, bread, coffee, and infant formula. 3-MCPD esters have also been detected in human breast milk, indicating their possible absorption and distribution in human organs and tissues. 3-MCPD esters have become a food safety concern, and in 2013 the European Food Safety Authority estimated a tolerable daily value (TDI) of 2 μg/kg body weight (BW) for the amount of free 3-MCPD. This review summarizes the available information on 3-MCPD ester research, including the analytical methods, exposure biomarkers, absorption and metabolism, toxicities, formation mechanisms, and mitigation strategies as well as the occurrence of 3-MCPD esters in human foods. This review may serve as a scientific foundation for advancing our understanding of 3-MCPD esters and their food safety concerns.

Comparison assessment between SIM and MRM mode in the analysis of 3-MCPD ester, 2-MCPD ester and glycidyl ester

The detection of 3- and 2-MCPD ester and glycidyl ester was transformed from selected ion monitoring (SIM) mode to multiple reaction monitoring (MRM) mode by gas chromatography triple quadrupole spectrometry. The derivatization process was adapted from AOCS method Cd 29a-13. The results showed that the coefficient of determination (R²) of all detected compounds obtained from both detection mode was comparable, which falls between 0.997 and 0.999. The limit of detection and quantification (LOD and LOQ) were improved in MRM mode as compared to SIM mode. In MRM mode, the LOD of 3- and 2-MCPD ester was achieved 0.01 mg/kg while the LOQ was 0.05 mg/kg. Besides, LOD and LOQ of glycidyl ester were 0.024 and 0.06 mg/kg respectively. A blank spiked with MCPD esters (0.03, 0.10 and 0.50 mg/kg) and GE (0.06, 0.24 and 1.20 mg/kg) were chosen for repeatability and recovery tests. MRM mode showed better repeatability in area ratio and recovery with relative standard deviation (RSD %) < 5% for 2-, 3-MCPD ester at 0.5 mg/kg and GE at 1.2 mg/kg. Quantification of 22 food samples from different category were performed by repeated injections in both detection modes. Briefly, the contaminants from crude palm oil, mustard and olive oil were present in minute amount which below the LOD or LOQ in both detection modes. Sample from chocolate and infant formula products showed certain level of MCPD esters and GE, and their detection was more precisely quantitated based on MRM mode. Besides, margarine products showed a higher level of contaminations due to the high fat content in these products. MRM mode detection was proven to provide precise data with low RSD % in different food matrices. MRM mode detection was robust and selective for MCPD esters and GE analyses, it should be applied to determine the concentration of MCPD esters and GE contaminations in food.

Rapid and Green Separation of Mono- and Diesters of Monochloropropanediols by Ultrahigh Performance Supercritical Fluid Chromatography-Mass Spectrometry Using Neat Carbon Dioxide as a Mobile Phase

This study demonstrates the effect of column selectivity and density of supercritical carbon dioxide (SC-CO₂) on the separation of monochloropropanediol (MCPD) esters, known as food toxicants, using SC-CO₂ without addition of cosolvent in ultrahigh performance supercritical fluid chromatography-mass spectrometry (UHPSFC-MS). This study shows that over 20 2-monochloropropanediol (2-MCPD) and 3-monochloropropanediol (3-MCPD) mono- and diesters are separated on a 2-picolylamine column in less than 12 min. The presence and position of a hydroxyl group in the structure, the number of unsaturated bonds, and the acyl chain length play a significant role in the separation of MCPD esters. The flow rate, backpressure, and column oven temperature, which affect the density of the mobile phase, were shown to have a substantial impact on retention, efficiency, and selectivity. The developed method was successfully applied for the determination of MCPD esters in refined oils and showed a close to excellent green analysis score using the Analytical Eco-Scale.

Identification of 3-MCPD esters to verify the adulteration of extra virgin olive oil

The adulteration of olive oil is an important issue around the world. This paper reports an indirect method by which to identify 3-monochloropropane-1,2-diol (3-MCPD) esters in olive oils. Following sample preparation, the samples were spiked with 1,2-bis-palmitoyl-3-chloropropanediol standard for analysis using gas chromatograph-tandem mass spectrometry. The total recovery ranged from 102.8% to 105.5%, the coefficient of variation ranged from 1.1% to 10.1%, and the limit of quantification was 0.125 mg/kg. The content of 3-MCPD esters in samples of refined olive oil (0.97-20.53 mg/kg) exceeded those of extra virgin olive oil (non-detected to 0.24 mg/kg). These results indicate that the oil refining process increased the content of 3-MCPD esters, which means that they could be used as a target compound for the differentiation of extra virgin olive oil from refined olive oil in order to prevent adulteration.

Assessment of critical steps of a GC/MS based indirect analytical method for the determination of fatty acid esters of monochloropropanediols (MCPDEs) and of glycidol (GEs)

Fatty acid esters of 2- and 3-chloropropanediol (MCPDEs) and fatty acid esters of glycidol (GEs) are commonly monitored in edible fats and oils. A recommendation issued by the European Commission emphasizes the need of generating data on the occurrence of these substances in a broad range of different foods. So far, analytical methods for the determination of MCPDEs and GEs are fully validated only for oils, fats and margarine. This manuscript presents the assessment of critical steps in the AOCS Cd 29a-13 method for the simultaneous determination of MCPDEs and GEs in the fat phase obtained from bakery and potato products, smoked and fried fish and meat, and other cereal products. The trueness of the method is affected by the additional formation of 3-MBPD esters from monoacylglycerols (MAGs), which are frequently present in food. The overestimation of GE contents for some samples was confirmed by the comparison of results with results obtained by an independent analytical method (direct analysis of GE by HPLC-MS/MS). An additional sample pre-treatment by SPE was introduced to remove MAGs from fat prior to the GEs conversion, while the overall method sensitivity was not significantly affected. Trueness of the determination of GEs by the modified analytical procedure was confirmed by comparison with a direct analysis of GEs. The potential impact on accuracy of results of the final sample preparation step of the analytical procedure, the derivatization of free forms MCPD and MBPD with PBA, was evaluated as well. Different commercial batches of PBA showed differences in solubility in a non-polar organic solvent. The PBA derivatization in organic solvent did not affect precision and trueness of the method due to the isotopic standard dilution. However, method sensitivity might be significantly compromised.

Novel fast analytical method for indirect determination of MCPD fatty acid esters in edible oils and fats based on simultaneous extraction and derivatization

A novel method for indirect determination of MCPD esters levels in lipid samples has been developed. The method is based on combination of extraction and derivatization in the same sample preparation step. It is achieved by the application of diethyl ether as extraction solvent for isolation of analytes released from esterified forms from the water phase and as dilution solvent for solid PBA – the derivatization agent. It is a noteworthy improvement of recommended indirect approaches available in the literature because such steps as sample clean-up, multiple liquid–liquid extractions, and preconcentration are excluded in the proposed solution. In this way, the developed procedure is shortened and simplified. Such an approach also minimizes the utilization of organic solvents; therefore, it is in accordance with the principles of “green analytical chemistry.” In spite of the fact that the step of sample clean-up is omitted, no deterioration in GC-MS system performance was observed. Equivalence testing of the developed procedure and AOCS cd 29b-13 official method (SGS) has been conducted. It was concluded that results obtained by both methods do not significantly differ statistically. The procedure has been applied to determination of MCPD esters concentrations in lipid fractions isolated by accelerated solvent extraction technique from such foodstuffs as bakery products, salty deep-fried snacks, and instant products. In all investigated samples, the level of bound MCPD was elevated. Additionally, for both procedures, the environmental impact (with the use of analytical Eco-scale) and uncertainty budget have been assessed and compared.

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

Glycidyl fatty acid esters (GEs), one of the main contaminants in processed oils, are mainly formed during the deodorization step in the refining process of edible oils and therefore occur in almost all refined edible oils. GEs are potential carcinogens, due to the fact that they readily hydrolyze into the free form glycidol in the gastrointestinal tract, which has been found to induce tumors in various rat tissues. Furthermore, glycidol has already been identified as a "possible human carcinogen'' (group 2A) by the Intl. Agency for Research on Cancer (IARC). Therefore, significant effort has been devoted to inhibit and eliminate the formation of GEs. The aim of this review is to provide a comprehensive summary on the following topics: (i) GE occurrence data for different edible oils and oil-based food products, (ii) precursors of GEs, (iii) factors influencing the formation of GEs, (iv) potential reaction mechanisms involving the leaving group and reaction intermediates, and (v) analytical methods, including the indirect and direct methods. More importantly, the various elimination methods for GEs in refined edible oils are being reviewed with focus on 3 aspects: (i) inhibition and removal of reactants, (ii) modification of reactive conditions, and (iii) elimination of GE products.

Extraction and Liquid Chromatography-Tandem Mass Spectrometry Detection of 3-Monochloropropanediol Esters and Glycidyl Esters in Infant Formula

A method was developed for the extraction of fatty acid esters of 3-chloro-1,2-propanediol (3-MCPD) and glycidol from infant formula, followed by quantitative analysis of the extracts using liquid chromatography-tandem mass spectrometry (LC-MS/MS). These process-induced chemical contaminants are found in refined vegetable oils, and studies have shown that they are potentially carcinogenic and/or genotoxic, making their presence in edible oils (and processed foods containing these oils) a potential health risk. The extraction procedure involves a liquid-liquid extraction, where powdered infant formula is dissolved in water and extracted with ethyl acetate. Following shaking, centrifugation, and drying of the organic phase, the resulting fat extract is cleaned-up using solid-phase extraction and analyzed by LC-MS/MS. Method performance was confirmed by verifying the percent recovery of each 3-MCPD and glycidyl ester in a homemade powdered infant formula reference material. Average ester recoveries in the reference material ranged from 84.9 to 109.0% (0.6-9.5% RSD). The method was also validated by fortifying three varieties of commercial infant formulas with a 3-MCPD and glycidyl ester solution. Average recoveries of the esters across all concentrations and varieties of infant formula ranged from 88.7 to 107.5% (1.0-9.5% RSD). Based on the validation results, this method is suitable for producing 3-MCPD and glycidyl ester occurrence data in all commercially available varieties of infant formula.

Decomposition products of glycidyl esters of fatty acids by heating

In this study, decomposition products of glycidyl palmitate (GP) of fatty acids heated at high temperature such as deep frying were investigated. When GP and tripalmitin (TP) were heated at 180 and 200 °C, they were decreased with heating time. The weight of GP was less than that of TP, although both GP and TP were converted to polar compounds after heating. The decomposition rate of GP was higher than TP. Both GP and TP produced considerable amounts of hydrocarbons and aldehydes during heating. Aldehydes produced from GP and TP included saturated aldehydes with carbon chain length of 3-10, while hydrocarbons consisted of carbon chain length of 8-15. It was observed that major hydrocarbons produced from GP during heating were pentadecane. Moreover, the level of carbon dioxide (CO₂) released from GP was higher than that of TP. It was suggested that fatty acids in GE might be susceptible to decarboxylation. From these results, GP might be quickly decomposed to hydrocarbons, aldehydes and CO₂ besides polar compounds by heating, in comparison with TP.