Determination of advanced glycation endproducts in cooked meat products

Abstract: Advanced glycation endproducts (AGEs), a pathogenic factor implicated in diabetes and other chronic diseases, are produced in cooked meat products. The objective of this study was to determine the AGE content, as measured by Nε-carboxymethyllysine (CML) levels, in cooked chicken, pork, beef and fish (salmon and tilapia) prepared by three common cooking methods used by U.S. consumers: frying, baking, and broiling. The CML was detected in all the cooked samples, but the levels were dependent on types of meat, cooking conditions, and the final internal temperature. Broiling and frying at higher cooking temperature produced higher levels of CML, and broiled beef contained the highest CML content (21.8 μg/g). Baked salmon (8.6 μg/g) and baked tilapia (9.7 μg/g) contained less CML as compared to the other muscle food samples.


Alex’s Notes: Advanced glycation endproducts (AGEs) are an interesting area of research. They are formed from a non-enzymatic reaction between reducing sugars (i.e. glucose) and free amino groups (i.e. amino acids). Research suggests that AGEs are implicated in aging, inflammation, and disease, although the mechanisms are not fully known, and dietary intake is a significant contributor of AGEs. Since we all cook our food (or I suppose I should say 99% of us do in case a raw foodie is reading this), it is worth looking at different cooking methods on AGE formation in meat.

The researchers bought beef rib round steak, pork top loin, skinless chicken breast, and tilapia and salmon fillets from a local market.

“Meat samples were prepared by pan frying at different desired surface temperatures, oven broiling at 232 °C (450 °F), and oven baking at 177 °C (350 °F). To eliminate foodborne illness, the internal cooking temperature was used according to recommendation of USDA-FSIS (1998): 63 °C (145 °F) for fish, 71 °C (160 °F) for pork, 74 °C (165 °F) for chicken, and 71 °C (160 °F, well done) for beef. To compare the AGEs levels in cooked meat with different degrees of doneness, the pork samples were fried to 63 °C (145 °F, medium), and the beef steak samples were also fried to 54 °C (130 °F, very rare), 63 °C (145 °F, medium), 71 °C (160 °F, well done) and 77 °C (170 °F, overdone). In order to compare the AGE contents in cooked meat by different frying methods, the beef samples were cooked to the same internal temperature of 71 °C (160 °F) by turning once (after 5 min) or multiple times (interval of 1 min). No salt, spice, and oil were used in the cooking procedures.”

First and foremost, all cooking methods increased AGE amount in all meat samples with the greatest AGE formation seen in broiling, followed by frying, and lastly baking. You can see the AGE levels (μg/g) in the table below.

Meat types



Raw (control)

Frying (out)

Frying (in)



Beef steak

2.05 ± 0.40

20.03 ± 0.83

3.13 ± 0.68

21.84 ± 0.28

14.31 ± 1.04

Pork top loin

1.98 ± 0.97

17.53 ± 1.48

1.09 ± 0.53

20.35 ± 1.64

12.53 ± 1.19

Chicken breast

1.48 ± 0.77

17.16 ± 1.43

2.99 ± 0.89

19.69 ± 0.78

13.58 ± 0.63


1.92 ± 0.61

12.20 ± 1.68

2.05 ± 0.63

12.23 ± 1.13

8.59 ± 1.07


1.07 ± 0.38

12.53 ± 1.19

3.43 ± 1.10

11.24 ± 1.25

9.72 ± 1.33

What the above makes clear is that AGEs are concentrated on the outside of the meat (comparing frying-out to frying-in) and that direct contact with the heat source creates more AGEs. The researchers took this a step farther to see the effects of cooking time on AGE formation by cooking the beef and pork to different degrees of “doneness.”  This is shown in the following table.

Cooked items

Internal temperature (°C)

Cooking temperature (°C)




Beef steak

54 (Very rare)

9.17 ± 0.58

9.87 ± 0.71


63 (Medium)

10.15 ± 1.43

10.52 ± 0.96


71 (Well done)

20.03 ± 0.82

16.30 ± 1.03


77 (Over done)

21.01 ± 1.92

16.56 ± 1.31


Pork top loin

63 (Medium)

13.29 ± 1.15

8.84 ± 0.66a


71 (Well done)

17.53 ± 1.48

17.44 ± 1.43b

Given the similarities of AGE amount between the degrees of doneness, it appears that internal temperature is the primary determinant of AGE formation until the meat is cook through (well done) at which point higher temperature take precedence.

Bottom line: If you want to minimize AGE formation then bake your meat whenever possible. If you are having a steak or other red meat, get medium or medium-rare (it tastes better anyway).

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