Effects of deodorization temperature and time on the formation of 3-MCPD, 2-MCPD, and glycidyl esters and physicochemical changes of palm oil

Chlorinated paraffins as chlorine donors for the formation of 2- and 3-chloropropanediols in refined vegetable oils

The knowledge of chloropropanediols (MCPD) fatty acid esters formation pathways is an important condition for these processing contaminants mitigation. This study aimed to assess the potential of a group of lipophilic environmental contaminants, polychlorinated alkanes, commonly known as chlorinated paraffins (CPs), to contribute to the formation of MCPD esters. Laboratory-scale model systems representing vegetable oils contaminated with both a technical mixture of short-chained CPs and individual short-chained CPs were designed and subjected to heat treatment (230 °C, 2 h) to simulate the deacidification and deodorisation processes. A substantial increase in MCPD content (up to 3.4 times the control levels) was observed in systems spiked with a technical mixture. MCPD formation seems to correlate very well with the concentration of CPs in these systems. Based on the generated data, we can conclude that the processing of vegetable oils contaminated with CPs might contribute to elevated concentrations of MCPD.

Fatty acid esters of 3-monochloropropane-1,2-diol and glycidol in palm oil: A review on current industrial-scale mitigation strategies, challenges and perspectives

Glycidyl ester (GE) and 3-monochloropropane-1,2-diol ester (3-MCPDE) are food contaminants formed during edible oil refining. Due to their potential human carcinogenicity, the European Commission has established regulatory limits for vegetable oil, including palm oil. While laboratory-scale studies have shown promising reductions, large-scale implementation remains challenging. This review examines current mitigation technologies for palm oil, evaluated from lab to plant scale, and explores the challenges of large-scale implementation. Effective methods, such as crude palm oil washing, bleaching with non-hydrochloric acid-activated bleaching earth, dual-temperature deodorisation, and double refining, have been successfully tested at pilot scale or larger. Particularly, crude palm oil washing is widely adopted to reduce 3-MCPDE, whereas double refining effectively targets GE. However, a combination of strategies is required to simultaneously reduce 3-MCPDE and GE. These measures often lead to increased costs, oil loss and wastewater generation, with potential impacts on product quality. Furthermore, maintaining crude palm oil quality through good harvesting and milling practices is essential for consistent mitigation results. Continued research is necessary to improve mitigation methods for greater cost efficiency and reduced environmental impact, with large-scale studies needed to validate lab-scale findings and facilitate industry adoption.

An integrated multi-omics analysis of the effects of the food processing-induced contaminant 2-monochloropropane-1,3-diol (2-MCPD) in rat heart

Many foods including edible oils contain 2-monochloropropane-1,3-diol (2-MCPD), a processing-induced chemical contaminant. Cardiotoxic effects have been shown to result from oral 2-MCPD exposure in rodents, but the underlying mechanisms of action remain poorly understood. We undertook a comprehensive multi-omics approach to assess changes at the transcriptomic, proteomic, and oxylipin levels in heart tissues from male F344 rats that were exposed to 0 or 40 mg/kg BW/day of 2-MCPD in the diet for 90 days, in a regulatory compliant rodent bioassay. Heart tissues were collected for RNA sequencing, quantitative PCR analysis, proteomic analysis via two-dimensional gel electrophoresis and mass spectrometry, and targeted lipidomic profiling by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Transcriptomic and proteomic data analyses revealed upregulation of immune/inflammatory response processes and downregulation of energy metabolism and cardiac structure and functions. Among differentially expressed gene-protein pairs, coronin-1A, a key leukocyte-regulating protein, emerged as markedly up-regulated. Oxylipin profiling highlighted a selective suppression of docosahexaenoic acid-derived metabolites, suggesting a disruption in cardioprotective lipid pathways. These findings suggest that 2-MCPD disrupts homeostasis through inflammatory activation and suppression of metabolic and cardiac function. This research provides insights into 2-MCPD's cardiotoxicity, emphasizing the need for further studies to support hazard characterization.

Chloropropanols and Their Esters in Food: An Updated Review

Chloropropanols, their fatty acid esters, and glycidol and its fatty acid esters (GEs) are process contaminants in foods that pose potential health risks. These contaminants typically arise during the deodorization process of vegetable oils, particularly in high concentrations within oils like palm oil and products derived from them, such as margarine, baked goods, pastries, and infant formula. Chloropropanol esters and GE can hydrolyze under the influence of lipases, forming chloropropanols. Elevated temperatures during food production can lead to the release of free 3-chloro-1,2-propanediol (3-MCPD) or free 2-chloro-1,3-propanediol (2-MCPD) in products containing both fat and salt. The exposure to these contaminants, especially for infants and young children, raises concerns about potential health hazards. While extensive research has focused on 3-MCPD, 2-MCPD, and GE, knowledge regarding other chloropropanols such as 1,3-dichloro-2-propanol (1,3-DCP), 2,3-dichloro-1-propanol (2,3-DCP), and their fatty acid esters remains limited. This review aims to provide a comprehensive overview encompassing formation mechanisms, analysis methods, toxicological implications, occurrence patterns, exposure levels, mitigation strategies, and legislative considerations concerning these contaminants.

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.

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.

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.

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.