Discrepancies in the analysis of 3-chloropropane-1,2-diol (3-MCPD) esters can be explained by the hypothesis that in some refined oils significant amounts of fatty acid esters of glycidol (glycidyl esters) are present in addition to 3-MCPD esters. Glycidyl esters were separated from triacylglycerols by gel permeation chromatography (GPC) and detected by gas chromatography-mass spectrometry (GC-MS). Six samples of palm oil and palm oil-based fats were analyzed by GPC and GC-MS. In chromatograms of all samples, significant peaks, retention time and mass spectra in conformity with self-synthesized glycidyl palmitate and glycidyl oleate were detectable. Quantification of individual glycidyl esters was not possible because of a lack of pure standards. Concentration of ester-bound glycidol in different samples of fats and oils was estimated using an indirect difference method. Glycidyl esters could be detected only in refined, but not in crude or native, fats and oils. The highest concentrations were detected in palm oil and palm oilbased fats. In a palm oil sample, glycidyl ester concentration varied according to different deodorization parameters, temperature, and time, while 3-MCPD ester concentration was relatively constant, indicating that mitigation of glycidyl esters possibly may be achieved by optimizing refining parameters.

A method for the determination of total 3-chloropropane-1,2-diol (3-MCPD) in edible fats and oils was presented. 3-MCPD was released from 3-MCPD fatty acid esters by transesterification with NaOCH 3 / methanol. After derivatization with phenylboronic acid, 3-MCPD was determined by GC-MS. Deuterium-labeled 3-MCPD was used as internal standard. In a model experiment, it was shown that acidic hydrolysis with methanol/sulfuric acid, which is normally used for the release of 3-MCPD from its esters, can cause problems because under acidic conditions additional 3-MCPD can be formed. No additional 3-MCPD was formed using NaOCH 3 /methanol for transesterification. Eleven samples of cold-pressed and refined safflower oils were analyzed with this method. Levels of total 3-MCPD were in the range from ,100 up to 3200 mg/kg.

Quality of deep-fried food is inseparably attached to the quality of the used deep-frying oil. Taste, flavor, shelf life, consumer acceptance, and safety of fried food essentially depend on frying oil quality. Evaluation of frying oil quality therefore is an important issue for both frying operators and official food control agencies. Organoleptic evaluation is an essential step in the monitoring of frying fat quality. Several official laboratory methods are available to support the sensory evaluation. Total polar materials (TPM) and polymer TAGs (PTG) are the most reliable parameters for this purpose. Recommended and widely accepted limits are 24% for TPM and 12% for PTG. When oxidative alterations strongly predominate over thermal alterations, sensory defects can appear before TPM and PTG reach recommended values. In that case additional parameters like anisidine value, carbonyl value, or epoxy fatty acids should be considered. A number of physical and chemical rapid methods are available. Despite the limited informative value and the possibility of error of rapid tests, they are essential for fryer operators, because they deliver information about fat quality in real-time. Most reliable for most applications are quick tests measuring TPM. A unique and powerful tool for the simultaneous detection of multiple parameters corresponding to thermal and oxidative alterations is near infrared spectroscopy (NIRS), which will become more and more important in future.

Esters of 2 - and 3-monochloropropane-1,2-diol (MCPD) and glycidol esters are important contaminants of processed edible oils used as foods or food ingredients. This review describes the occurrence and analysis of MCPD esters and glycidol esters in vegetable oils and some other foods. The focus is on the analytical methods based on both direct and indirect methods. Methods of analysis applied to oils and lipid extracts of foods have been based on transesterification to free MCPD and determination by gas chromatography-mass spectrometry (indirect methods) and by high-performance liquid chromatography-mass spectrometry (direct methods). The evolution and performance of the different methods is described and their advantages and disadvantages are discussed. The application of direct and indirect methods to the analysis of foods and to research studies is described. The metabolism and fate of MCPD esters and glycidol esters in biological systems and the methods used to study these in body tissues studies are described. A clear understanding of the chemistry of the methods is important when choosing those suitable for the desired application, and will contribute to the mitigation of these contaminants.

Many studies and surveys concerning the ocurrence and exposure of free 3-MCPD have been performed in the last 30 years. Although a huge number of food samples, especially fats and oils, were analysed in the last 3 years, no systematic study about ester-bound 3-MCPD and the resulting exposure was performed up to now. In this paper published data of 3-MCPD esters in different foods are reviewed, with a focus on fats and oils and infant formula. Concerning fats and oils, only in refined products significant concentrations of 3-MCPD esters in a range from 0.25-15 mg/kg were present, with the highest levels found in palm oil. In infant formula, levels of esterlinked 3-MCPD were nearly unchanged in three surveys from April 2009 to May 2010, while levels of ester-linked glycidol decreased dramatically in this period. Based on analytical data of more than 200 refined fats and oils, an average daily intake of 1.5 mg 3-MCPD/kg bw/day, respectively, 0.9 mg glycidol/kg bw/day was calculated to result from consumer exposure to ester-bound 3-MCPD and glycidol.