An improved method for the measurement of 3‐monochloropropanediol esters by matrix solid‐phase dispersion supported liquid–liquid extraction

3‐Monochloropropanediol (3‐MCPD) esters are contaminants produced from the high‐temperature processing of edible oils. The accurate measurement of 3‐MCPD using an easy‐to‐follow and reliable method that uses a readily available instrument is important. Here, we report an acid transesterification heptafluorobutyrylimidazole (HFBI) derivatisation method for the accurate measurement of 3‐MCPD esters in edible oils. We developed a dispersed matrix solid‐phase supported liquid–liquid extraction (DMSP‐SLE) system to remove impurities. Both the transesterification and DMSP‐SLE conditions were optimised. A good linear relationship was obtained within the range of 0.05–10 mg kg^?1 (R² ≥ 0.999) in both blank solvent and an oil sample. The limit of detection was 20.36 μg kg^?1. The average recovery of the 3‐MCPD esters spiked at 0.5, 1.0 and 2.0 mg kg^?1 into a blank oil matrix was in a range from 105.09 ± 2.77% to 120.16 ± 10.88%. The method we developed was further confirmed by performing detection on a Food Analysis Performance Assessment Scheme (FAPAS) sample.     

3‐Chloropropane‐1,2‐diol (3‐MCPD) in Soy Sauce: A Review on the Formation,Reduction, and Detection of This Potential Carcinogen

Soy sauce, a dark‐colored seasoning, is added to enhance the sensory properties of foods. Soy sauce can be consumed as a condiment or added during the preparation of food. There are 3 types of soy sauce: fermented, acid‐hydrolyzed vegetable protein (acid‐ HVP), and mixtures of these. 3‐Chloropropane‐1,2‐diol (3‐MCPD) is a heat‐produced contaminants formed during the preparation of soy sauce and was found to be a by‐product of acid‐HVP‐produced soy sauce in 1978. 3‐MCPD has been reported to be carcinogenic, nephrotoxic, and reproductively toxic in laboratory animal testing and has been registered as a chemosterilant for rodent control. 3‐MCPD is classified as a possible carcinogenic compound, and the maximum tolerated limit in food has been established at both national and international levels. The purpose of this review is to provide an overview on the detection of 3‐MCPD in soy sauce, its toxic effects, and the potential methods to reduce its concentration, especially during the production of acid‐HVP soy sauce. The methods of quantification are also critically reviewed with a focus on efficiency, suitability, and challenges encountered in analysis.     

食用植物油中脂肪酸氯丙醇酯形成机制的研究进展

脂肪酸氯丙醇酯的污染是近年来国际上新出现的热点食品安全问题之一,尤其是脂肪酸3-氯-1,2-丙二醇酯（3-chlorine-1,2-propylene glycol ester,3-MCPD酯）污染问题更为突出。研究表明,食用植物油中3-MCPD酯主要形成于精炼过程,而未精炼的食用植物油几乎不含3-MCPD酯。欧盟国家已对食用植物油中3-MCPD酯的形成机制开展了相关研究。本文主要对食用植物油种类、可能的前体物质、精炼工艺与3-MCPD酯形成的关系加以综述。     

婴配食品中氯丙醇酯的污染来源及控制措施

氯丙醇酯类污染物主要形成于植物油精炼过程的脱臭工序,在食品加工过程中其含量也可能会变化。不同种类的油脂中污染物含量水平不同,不同工艺生产的同种油脂中污染水平也有较大差异,通过改善生产工艺可在较大程度上减少该污染物的含量。精炼植物油是婴配食品中脂肪的重要来源,在迚行产品配方设计时,不仅应考虑使其脂肪及脂肪酸在含量与结构上与母乳匹配,还应考虑可能引入的氯丙醇酯类污染物含量水平,尽可能从源头上减少此类污染物的带入。本文通过介绍氯丙醇酯的形成机制、婴配食品中脂肪来源及生产工艺及氯丙醇酯类污染物的主要类型,以确定该污染物的来源,幵提出可采取的延缓措施,从而帮助生产企业从理论和实践水平上控制此类污染物的暴露水平。     

植物油精炼过程中缩水甘油酯和3-氯丙醇酯的形成及脱除研究进展

缩水甘油酯(GEs)和3-氯丙醇酯(3-MCPDE)是植物油精炼过程中产生的主要污染物之一。GEs和3-MCPDE伴随食用油摄入人体后,经脂肪酶水解产生的缩水甘油和3-氯丙醇具有肾脏毒性和遗传毒性。植物油中GEs和3-MCPDE主要产生于油脂精炼脱臭工段,脱臭温度、脱臭时间对GEs和3-MCPDE的生成影响巨大。从油脂精炼加工过程中GEs和3-MCPDE的形成及脱除等方面进行了综述,指出脱色和脱臭工段可促进GEs和3-MCPDE的生成,当前可通过抑制及脱除其前体物质、优化植物油脱臭条件、脱除精炼油中的GEs及3-MCPDE等方式降低植物油中GEs和3-MCPDE含量。酶制剂具有安全、无污染等优点,通过酶法酯交换降低待脱臭油脂中的甘油二酯和甘油单酯,进而减少脱臭过程中GEs及3-MCPDE的生成是降低GEs和3-MCPDE的发展趋势。     

Toxicological assessment of 3-chloropropane-1,2-diol and glycidol fatty acid esters in food

Fatty acid esters of 3‐chloropropane‐1,2‐diol (3‐MCPD) and glycidol are a newly identified class of food process contaminants. They are widespread in refined vegetable oils and fats and have been detected in vegetable fat‐containing products, including infant formulas. There are no toxicological data available yet on the 3‐MCPD and glycidol esters, and the primary toxicological concern is based on the potential release of 3‐MCPD or glycidol from the parent esters by lipase‐catalyzed hydrolysis in the gastrointestinal tract. Although 3‐MCPD is assessed as a nongenotoxic carcinogen with a tolerable daily intake (TDI) of 2 μg/kg body weight (bw), glycidol is a known genotoxic carcinogen, which induces tumors in numerous organs of rodents. The initial exposure estimates, conducted by Federal Institute for Risk Assessment (BfR) under the assumption that 100% of the 3‐MPCD and glycidol are released from their esters, revealed especially that infants being fed commercial infant formula could ingest harmful amounts of 3‐MCPD and glycidol. However, the real oral bioavailability may be lower. As this gives rise for toxicological concern, the currently available toxicological data of 3‐MCPD and glycidol and their esters are summarized in this review and discussed with regard to data gaps and further research needs.     

油脂脱臭过程氯离子含量对3-氯丙醇酯和缩水甘油酯的影响

对油脂脱臭用直接蒸汽水源中氯离子含量和待脱臭油脂中氯离子含量进行检测分析,并采用不同氯离子含量的直接蒸汽对油脂进行蒸馏脱臭,检测脱臭前后油脂中3-氯丙醇酯（3-monochloro-1,2-propanediol ester,3-MCPD酯）和缩水甘油酯（glycidyl esters,GEs）含量及氯离子含量,研究油脂脱臭过程氯离子含量对脱臭油脂中3-MCPD酯和GEs的影响。结果表明：油脂脱臭用直接蒸汽中氯离子含量随其水源中氯离子含量增加而升高,水源中氯离子含量在对应饱和蒸汽中的保留率约为0.1%;当油脂脱臭用直接蒸汽水源中氯离子质量浓度达到50～200?mg/L时,脱臭油脂中3-MCPD酯含量大幅升高至低质量浓度氯离子水源（1～10?mg/L）脱臭油脂中含量的2.6?倍,但脱臭油脂中氯离子含量并未升高;待脱臭油脂中氯离子含量升高会导致脱臭后油脂中3-MCPD酯和GEs含量的升高。在待脱臭油脂中添加质量浓度为100?mg/L的氯化钠溶液0.5～5?mL时（相当于油脂中添加量1～10?mg/kg）,脱臭后油脂中3-MCPD酯和GEs生成量分别为4.49～7.84?mg/kg和14.88～19.84?mg/kg,是待脱臭油脂含量的5.5～9.5?倍和5.8～7.7?倍。因此,控制和减少油脂脱臭过程氯离子含量对降低脱臭油脂中3-MCPD酯和GEs含量有重要作用。     

食用油中3-氯-1,2-丙二醇酯的研究进展

3-氯-1,2-丙二醇酯是形成于食用油加工过程中的污染物质。在对食用油中3-氯-1,2-丙二醇酯文献分析的基础上,综述了食用油中3-氯-1,2-丙二醇酯的研究进展,主要包括氯丙醇类物质的结构类型;不同国家和地区的污染水平现状及限量标准;近期建立的检测方法;氯化物和脂类前体物质以及形成原理;精炼前、精炼中和精炼油到成品油3个阶段的控制措施。同时指出了现阶段主要存在的问题,并对今后研究的方向和重点进行了展望。旨在为完善有效控制油脂加工过程中3-氯-1,2-丙二醇酯的产生、保障油脂安全提供依据。     

承德市食用植物油中氯丙醇酯和缩水甘油酯污染水平与暴露风险评估

目的对承德市售食用植物油中氯丙醇酯和缩水甘油酯进行污染水平分析。方法样品加入适量内标液后,经碱水解脂肪,固相萃取柱脱水净化后,用七氟丁酰基咪唑进行衍生化处理,供气相色谱-质谱仪进样分析。结果在检测的市售的30份植物油样品中,3-氯丙醇酯、2-氯丙醇酯和缩水甘油酯的检出率为100%、93%(28/30)及83%(25/30)。3-氯丙醇酯及2-氯丙醇酯含量范围分别在0.15～1.06 mg/kg和0.03-0.66 mg/kg,缩水甘油酯含量范围在0.03～1.85 mg/kg。结论氯丙醇酯和缩水甘油酯污染在承德市食用植物油中广泛存在,检出率在80%以上,这意味着虽然通过食用植物油摄入氯丙醇酯和缩水甘油酯的健康风险不高,但仍然不能忽视这种风险。检测部门应加大对这两种物质的检测力度,以保障人民的健康安全。     

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

ABSTRACT

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.     

基于植物油中脂肪酸烷基酯含量变化鉴别废弃油脂

采用固相萃取柱净化,气相色谱-质谱联用法测定了6种植物油中脂肪酸烷基酯(包括脂肪酸甲酯和脂肪酸乙酯)的含量,并研究其在植物油煎炸、废弃及废弃油脂精炼等环节中的变化。结果发现,6种植物油中脂肪酸烷基酯的含量均低于30 mg/kg,而植物油在废弃过程中可能会形成大量脂肪酸乙酯,生成量与油脂是否烹饪及废弃物中乙醇含量有关。脂肪酸烷基酯在脱色工艺中不能被去除,但在脱臭中可被去除。因此,可以通过测定植物油中脂肪酸烷基酯含量发现废弃油脂,为废弃油脂的鉴别工作提供新的思路。     

Regioisomeric distribution of 9‐ and 13‐hydroperoxy linoleic acid in vegetable oils during storage and heating

BACKGROUND

The oxidative deterioration of vegetable oils is commonly measured by the peroxide value, thereby not considering the contribution of individual lipid hydroperoxide isomers, which might have different bioactive effects. Thus, the formation of 9‐ and 13‐hydroperoxy octadecadienoic acid (9‐HpODE and 13‐ HpODE), was quantified after short‐term heating and conditions representative of long‐term domestic storage in samples of linoleic acid, canola, sunflower and soybean oil, by means of stable isotope dilution analysis–liquid chromatography‐mass spectroscopy.

RESULTS

Although heating of pure linoleic acid at 180 °C for 30 min led to an almost complete loss of 9‐HpODE and 13‐HpODE, heating of canola, sunflower and soybean oil resulted in the formation of 5.74 ± 3.32, 2.00 ± 1.09, 16.0 ± 2.44 mmol L^–1 13‐HpODE and 13.8 ± 8.21, 10.0 ± 6.74 and 45.2 ± 6.23 mmol L^–1 9‐HpODE. An almost equimolar distribution of the 9‐ and 13‐HpODE was obtained during household‐representative storage conditions after 56 days, whereas, under heating conditions, an approximately 2.4‐, 2.8‐ and 5.0‐fold (P ≤ 0.001) higher concentration of 9‐HpODE than 13‐HpODE was detected in canola, soybean and sunflower oil, respectively.

CONCLUSION

A temperature‐dependent distribution of HpODE regioisomers could be shown in vegetable oils, suggesting their application as markers of lipid oxidation in oils used for short‐term heating. © 2017 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

应用脂肪酸甲酯快速筛选植物油中掺假地沟油

根据植物油和地沟油中脂肪酸酯存在方式的不同,建立植物油中地沟油掺假的快速筛选方法。植物油中脂肪酸是以甘油三酯的形式存在,地沟油中脂肪酸以脂肪酸甲酯的形式存在,利用气相色谱-质谱的全扫描模式,结合NIST 05标准谱库检索功能,对37 种脂肪酸甲酯进行测定。样品采用直接稀释-气相色谱-质谱全扫描分析脂肪酸甲酯,100 个植物油样品中均未检出脂肪酸甲酯;20 个地沟油样品中13 个检出肉豆蔻酸甲酯（C14∶0）、棕榈酸甲酯（C16∶0）和硬脂酸甲酯（C18∶0）等14 种脂肪酸甲酯,检出率为65%,且70%的检出脂肪酸甲酯的地沟油样品中脂肪酸甲酯种类多、含量较高。因此,若植物油样品脂肪酸甲酯种类多、含量高,则可判定为有地沟油掺假;若脂肪酸甲酯含量低或没有脂肪酸甲酯,则可以进一步用其他指标和方法进行检测,脂肪酸甲酯的检测方法可以作为地沟油掺假的快速粗筛方法。     

食用油中3-氯-1,2-丙二醇酯检测方法的研究进展

3-氯-1,2-丙二醇酯(3-MCPD酯)是油脂精炼过程中引入的又一潜在危害因子,它是3-氯丙醇与脂肪酸的酯化产物.目前3-MCPD酯测定方法的研究已成为当今食品安全检测的一大热点.本文综述了近几年来国内外食用油中3-MCPD酯的检测方法,包括酸催化酯交换间接测定法、碱催化酯交换间接测定法以及直接测定法,详细介绍了各种检测方法的研究现状及优缺点,并讨论了未来3-MCPD酯检测技术的研究发展方向,为今后我国建立食用油中3-MCPD酯标准分析方法提供参考和依据.     

玉米油精炼过程氯离子含量变化及其对3-氯丙醇酯和缩水甘油酯含量的影响

对取自安徽、河北、山东等地玉米油加工厂的玉米油毛油、待脱臭油和成品油中的氯离子、3-氯丙醇（3-monochloro-1,2-propanediol,3-MCPD）酯和缩水甘油酯（glycidyl esters,GEs）含量进行检测,并在实验室明确可控的条件下对玉米毛油进行精炼,检测精炼过程氯离子、3-MCPD酯和GEs含量,与玉米油加工厂实际精炼过程的含量变化情况进行对比分析,研究玉米油精炼过程中氯离子含量变化及其对3-MCPD酯和GEs含量变化的影响。结果表明：所检测的所有玉米油样品中均含有氯离子、3-MCPD酯和GEs,其中毛油中氯离子含量最高,为0.628～2.029 mg/kg,毛油中3-MCPD酯和GEs含量分别为0.547～1.083 mg/kg和0.246～0.721 mg/kg;待脱臭玉米油中氯离子含量为0.110～0.374 mg/kg,较毛油中含量明显降低,3-MCPD酯和GEs含量分别为0.933～1.422 mg/kg和0.246～0.432 mg/kg,3-MCPD酯较毛油中含量有所升高,GEs含量变化不明显。脱臭油中3-MCPD酯和GEs含量分别为3.523～4.541 mg/kg和1.501～13.584 mg/kg,较待脱臭油中含量大幅升高,其中一个油样中含量分别增加3.5 倍和32.1 倍,同时该油样中氯离子含量的降幅也最大（0.287 mg/kg）。对实验室精炼过程及工厂精炼过程的玉米油样品检测分析显示,无论是实验室精炼还是工厂实际生产,氯离子含量均随精炼过程逐渐减少,其中降幅最大的是水化脱胶和碱炼脱酸工序（降幅为76.1%～81.3%）;3-MCPD酯和GEs在水化脱胶、碱炼脱酸及吸附脱色过程的含量变化不大,经脱臭后含量大幅升高,同时伴随脱臭过程氯离子含量的降低,并且氯离子含量降幅越大3-MCPD酯的升幅越高。研究结果明确了玉米油精炼过程氯离子和3-MCPD酯及GEs含量的变化规律,以及待脱臭玉米油中氯离子含量对脱臭油脂中3-MCPD酯和GEs含量的影响,对玉米油精炼乃至其他植物油生产中3-MCPD酯和GEs的风险防范和控制都具有指导意义。     

Fatty acid esters of monochloropropanediol (MCPD) and glycidol in refined edible oils

Recently, fatty acid esters of monochloropropanediol (MCPD) and that of glycidol have been reported in refined edible oils. Since then a wealth of research has been published on the factors influencing the formation of these contaminants in foods. It can be noted that the predominant precursors in a given matrix will not necessarily be the same as in other matrices. Further, proven relationships in the past between precursors responsible for free MCPD or free glycidol formation will not necessarily be valid for their fatty acid-esterified counterparts. This review attempts to summarise the current status of the literature as it pertains to the reasons surrounding the manifestation of MCPD esters and glycidyl esters in oils and fats. Recent efforts to mitigate the levels of these contaminants were highlighted and put into the context of their respective reaction matrices. As more accurate occurrence data for MCPD esters and glycidyl esters in other foods are collected, more targeted mitigation experiments can be formulated with respect to the reaction matrices under investigation.     

Updated occurrence of 3-monochloropropane-1,2-diol esters (3-MCPD) and glycidyl esters in infant formulas purchased in the United States between 2017 and 2019

ABSTRACT

Fatty acid esters of 3-monochloropropane-1,2-diol (3-MCPD) and glycidol are potentially carcinogenic and/or genotoxic processing contaminants that are formed during the process of edible oil refining. Because of their toxicological properties, the presence of these compounds in refined oils and foods containing these oils, particularly infant formula, poses a potential food safety concern. For this reason, recent research efforts have focussed on the development of methods for the analysis of MCPD and glycidyl esters in infant formula in order to estimate levels of exposure. This work presents occurrence data for 3-MCPD and glycidyl esters in 222 infant formulas purchased in the United States between December 2017 and January 2019. The results of this study show a wide range of contaminant concentrations across four different manufacturers, with average bound 3-MCPD concentrations ranging from 0.035 µg g^?1 to 0.63 µg g^?1 and average bound glycidol concentrations ranging from 0.019 µg g^?1 to 0.22 µg g^?1. The data suggest that manufacturers B and C source palm oil produced with mitigation measures, leading to reduced amounts of 3-MCPD and glycidyl esters in their infant formulas. Additionally, comparison with a previously published study in our laboratory of the occurrence of 3-MCPD and glycidyl esters in infant formula purchased in the U.S. between 2013 and 2016 revealed that, since 2016, contaminant concentrations have decreased in products produced by manufacturers A, B, and C, while contaminant amounts in formulas from manufacturer D have slightly increased.     

食用油中3-氯丙醇酯的研究进展

氯丙醇酯污染是近年来国际上出现的食品安全热点问题之一,尤其是3-氯丙醇酯污染更为突出,各种食用油或油脂食品中都含有一定量的3-氯丙醇酯。总结了国内外对3-氯丙醇酯的研究现状,介绍了3-氯丙醇酯来源、毒理和安全性、可能的形成机制、检测方法、污染水平、控制措施和精炼过程中形成的影响因素等方面的内容,并提出了目前急需解决的问题。旨在推动我国油脂食品行业的健康发展。     

婴幼儿配方奶粉及其配料油脂成分中有害酯类的污染差异分析

建立油脂和奶粉中3-氯丙醇酯、2-氯丙醇酯和缩水甘油酯的气相色谱-质谱检测方法,测定植物油脂及婴幼儿配方奶粉中的酯类污染物含量,并开展3 种有害酯类在不同种类油脂中的污染差异分析,以及与奶粉脂肪含量的相关性研究。婴幼儿配方奶粉常用植物油配料种类中,棕榈油是污染水平最高的油脂品种;其次是菜籽油、大豆油、玉米油和食用植物调和油;葵花籽油、椰子油、核桃油、亚麻籽油污染水平较低;1,3-二油酸-2-棕榈酸甘油三酯（1,3-dioleic acid-2-triglyceride palmitate,OPO）结构油脂、食用植物调合油（含OPO）污染水平最低。95 份婴幼儿配方奶粉中88.4%检出3-氯-1,2-丙二醇酯（3-monochloropropane-1,2-diol ester,3-MCPDE）,含量范围为ND～0.231 mg/kg,平均值0.070 4 mg/kg,中位值0.064 5 mg/kg;42.1%检出2-MCPDE,含量在ND～0.034 mg/kg之间;缩水甘油酯的检出率为2.1%,含量为ND～0.019 mg/kg。10.5%的奶粉样本中3-MCPDE含量超过欧盟0.125 mg/kg的限量值。奶粉中3 种酯类污染物总量与奶粉脂肪含量之间存在显著正相关,Pearson相关系数为0.453。为保护婴幼儿的安全,生产厂家应谨慎选择原料油脂,在确保营养健康的基础上尽可能降低婴幼儿配方奶粉中有害酯类的污染。     

Change of fatty acid esters of MCPD and glycidol during restaurant deep frying of fish nuggets and their correlations with total polar compounds

This study examined the fatty acid esters of 2-monochloropropane-1,2-diol (2-MCPD), 3-monochloropropane-1,2-diol (3-MCPD) and glycidyl esters (GEs) in frying oils during fish nuggets deep frying. The 3-MCPD esters significantly increased in the first 12 h and then decreased, whereas 2-MCPD esters increased to a maximum at 24 h (0.69–0.81 mg kg⁻¹) and then decreased. The GEs decreased with frying time and degraded to approximately 0.05 mg kg⁻¹ after 36 h in all frying oils. The correlation results showed that the 3-MCPD esters had a positive correlation with 2-MCPD esters (R = 0.910), so 3-MCPD esters could be an indicator of the presence of MCPD esters in frying oils. Strong correlations were found between MCPD esters and the peroxide values and p-anisidine values, indicating that changes in MCPD esters may be related to oil oxidation. These results may improve our understanding of MCPD esters and GEs in frying oils and find ways to control them during frying.