Is there a risk of formation of glycidyl esters of fatty acids in meat

Glycidyl esters of fatty acids (GE) belong to the group of contaminants that are formed under high temperature conditions during the production of edible oils. Diacylglycerol (DAG) oil was found to contain significantly higher GE levels compared to other commercial edible oils and was therefore discontinued. Glycidyl esters of fatty acids (GE), such as glycidyl palmitate (C16:0-GE), glycidyl stearate (C18:0-GE), glycidyl oleate (C18:1-GE), glycidyl linoleate (C18:2-GE) and glycidyl linolenate (C18:3-GE), are present in diacylglycerol (DAG) oil in high concentration. The formation of GE can occur during cooking with all refined edible oils and processed foods made with these oils (Kuhlmann, 2011). contains a reactive epoxy site in its structure.

Glycidol has been reported for its genotoxicity and carcinogenicity (El Ramy et al., 2007), and according to a study by the National Toxicology Program, it is considered to be carcinogenic to rodents. The International Agency for Research on Cancer (IARC) has defined glycidol as a group 2A carcinogen ("probably carcinogenic to humans"). Therefore, human exposure is of concern because glycidol is ingested through GE-containing foods. Since edible meat and fish contain fatty substances, GE can be formed in meat and fish heated at a high cooking temperature.

In one scientific study (Inagaki et al. 2016), for the analysis of the presence of glycidyl esters of fatty acids (GE), 100 g of mixed meat was taken and patties were made. The size of each patty was 1.0 cm thick and 10 cm in diameter. A pan was used for grilling patty samples, where the meat was grilled over gas, and a grill where the meat was grilled over charcoal. The baking method in a Teflon-coated pan was carried out at a temperature of 150 ˚C (low temperature) and at a temperature of 250 ˚C (high temperature). Then, the meat patty samples were baked for a total of 20 minutes at a low temperature and 10 minutes at a high temperature without adding oil. To grill meat over a charcoal grill, approximately 1.0 kg of charcoal was placed at the bottom of the grill oven and a fire was lit. When all the flames died down, the coal was leveled with a rake. The patty samples were then grilled over charcoal for 5 minutes. The distance between the samples and the charcoal was about 2 cm. The average temperature of an open charcoal fire was around 400°C.

No GE was detected in pork and beef samples at a low cooking temperature (150°C) using a gas pan. At high temperature (250°C), GE were determined in pork samples roasted for 5 minutes (34.4 ± 1.5 ng) and 10 minutes (166.1 ± 6.8 ng/g) and beef samples roasted for 10 minutes (65.7 ± 6.2 ng/g). These results showed that the amount of GE formed in meat samples can increase with increasing temperature and cooking time. However, GEs were not detected in chicken cooked at a high temperature (250°C). The fat and water content in raw pork, beef and chicken meat samples was 0.15, 0.14 and 0.08 g fat/g, respectively 0.64, 0.65 and 0.70 g water/g. The fat content is lower and the water content is higher in raw chicken meat samples than in pork and beef samples.

The chicken meat samples may not have been able to be heated sufficiently from the inside under gas pan cooking conditions. Therefore, GE could not be formed in chicken meat samples.

The temperature of the charcoal grill was higher than the temperature of the gas pan. The grilling temperature range on the charcoal grill was from 350 °C to 600 °C. The average content of total GE in roasted pork samples was 1083.5 ± 602.9 ng/g. The average content of total GE in grilled beef samples was 669.5 ± 526.0 ng/g and the average content of total GE in grilled chicken meat samples was 1106.6 ± 475.3 ng/g.

From these results of roasted pork, beef, and chicken samples, the GE levels in the charcoal grilled meat samples were much higher than those in the gas pan roasted meat samples. This is because the grilling temperature on a charcoal grill was much higher than that of a gas pan. The temperature range was from 350°C to 600°C. GE formation in roasted meat samples can increase with increasing temperature, especially under very high temperature conditions such as charcoal grilling. The level of each GE in charcoal-grilled meat samples may also be proportional to the content of each fatty acid in raw meat samples. Therefore, GEs can be formed from any corresponding fatty acid directly under high temperature conditions. Charcoal grilling meat was inedible in terms of visual presentation, burn deposits, hardness and GE generation. However, roasting meat in a pan contributes to a healthier diet and reduces the risk of exposure to mutagens. Rice oil contains approximately 2 μg/g of GE, and 1 g of DAG oil has approximately 200 μg/g of GE. The concentration of GE in 100 g of patties grilled on charcoal is equivalent to the amount of GE in 1 g of DAG. Although the sale of DAG oil has been suspended, the results show that GE is contained in roast meat even without DAG oil or other refined oils.