Analysis of MCPD and glycidol esters in food
Eurofins expands the application of the Zwagerman method to food
May 2023 (update). Since the beginning of 2023, the Eurofins Competence Centre for Organic Contaminants offers the analysis of monochloropropanediol (MCPD) and glycidyl esters in addition to fats and oils also in food by using the "Zwagerman method". In addition to the long-established "DGF method", the method portfolio thus includes another rapid method with the advantage of a direct determination of glycidol.
MCPD and glycidyl esters in brief
2-Monochloropropane diol esters (2-MCPD esters), 3-monochloropropane diol esters (3-MCPD esters) and glycidyl esters are contaminants that can occur during the refining of fats and oils. Their content in the final product depends on both the intensity of industrial processing and the raw material. Palm oils, for example, are particularly susceptible to the formation of MCPD esters due to their high diglyceride content.
During digestion, MCPD and glycidyl esters are converted into free MCPD and glycidol, respectively, which are considered carcinogenic. The tolerable daily intake (TDI) set by the European Food Safety Authority (EFSA) in 2018 is 2 µg/kg body weight per day (DOI: 10.2903/j.efsa.2018.5083).
Analysis of MCPD and glycidyl esters - Methods available
Due to the large number of possible fatty acid residues and their combination, MCPD and glycidyl esters are a complex group of substances. In the past, various indirect sum methods for the analysis of MCPD and glycidyl esters were developed, which are published as ISO or AOCS methods and find application in practice, such as the "DGF method", the "SGS method", the "Unilever method" and the "Zwagerman method".
The methods differ in the complexity of the sample preparation steps, the processing time required, the number of batches required per sample and thus the resulting equipment capacity, and last but not least the simplicity of automation. An essential difference is the determination of glycidol. The "DGF method" calculates the glycidol as a difference, whereas the other three methods mentioned include a direct determination of the glycidol.
"Zwagerman method" and other existing methods in comparison
The newly implemented "Zwagerman method" combines various methodological advantages: due to a short reaction time, it has advantages in the turnaround time, a single batch per sample reduces the necessary instrument capacity, and automation – as applied at Eurofins – is technically relatively easy. In addition, the "Zwagerman method" has the advantage of direct determination of glycidol. A complex validation study was successfully carried out for various oils and fats.
Method |
"DGF" |
"SGS" |
"Unilever" |
"Zwagerman" |
|
ISO method |
18363-1:2015 |
18363-2:2018 |
18363-3:2017 |
18363-4:2020 |
|
AOCS method |
Cd 29c-13 |
Cd 29b-13 |
Cd 29a-13 |
Cd 29d-20 |
|
Short TAT possible |
X |
- |
- |
X |
|
Simple automation possible |
X |
(X) |
(X) |
X |
|
Single batch / lower device capacity |
- |
X |
X |
x |
|
Direct determination of glycidol |
- |
X |
X |
X |
Table 1: Pros and cons of the existing methods for the analysis of MCPD and glycidyl esters
Further relevant matrices will be added to the application spectrum of the "Zwagerman method" at Eurofins in the course of the coming months. In addition to fats and oils and foodstuffs, the proven "DGF method" can currently be used for the analysis of all other matrices such as lecithins and emulsifiers.
Legal provisions for MCPD and glycidyl esters
Commission Regulation (EU) 2023/915 on the contaminants in foodstuffs sets maximum levels for glycidyl fatty acid esters and the sum of 3-MCPD and 3-MCPD esters in the following product groups:
- vegetable oils and fats
- fish oils and oils from other marine organisms
- vegetable oils and fats, fish oils and oils from other marine organisms destined for the production of baby food and processed cereal-based food for infants and young children
- infant formulae and follow-on formula (powdered and liquid)
- foods for special medical purposes (FSMP) for infants and young children (powdered and liquid)
At EU level, there are draft plans for setting maximum levels for additional food groups as well as for the emulsifier E471 (mono- and diglycerides of fatty acids).
In addition, maximum levels for free 3-MCPD in hydrolysed vegetable protein and soy sauce have been in place for several years.
Do you have further questions on the analysis of MCPD and glycidyl esters?
Please contact our expert Sabrina Hansen or your personal account manager – we are looking forward to enquiry!
