water-soluble reactants can leach out of the product and collect
on the surface enhancing Maillard endproduct formation.
High
cooking temperature accelerates this process, which may
explain why high cooking loss correlates to the high levels of
CML.
We investigated the occurrence of CML in broiled meats
(Table 3).
There is no significant difference among beef, pork and
chicken (p > 0.05).
However, it is evident that there were lower
levels of CML in the broiled salmon and tilapia as contrasted to
the other meat items (p < 0.05).
The results of the baked samples
are also in Table 3, and the CML contents in the fish (salmon and
tilapia) ranked relatively lower compared to the muscle meat samples
(p < 0.05).
Among all the fried samples, the highest level of
CML was found in beef steak (20.03 lg/g), followed by pork
(17.53 lg/g) and chicken (17.16 lg/g). They were all significantly
higher than those in salmon (12.20 lg/g) and tilapia (12.53 lg/g).
The different chemical ingredients in the raw meat products
(Table 1) may be responsible for the differences of the CML levels
to some extent in our study.
Although we found less CML in fried fish than in fried muscle
meat, Chao et al. (2009) reported salmon had the highest level of
CML in fried fish and meat samples. Moreover, there were no significant
differences in CML between fried pork and chicken
(p > 0.05).
However, it was not in agreement with the report from
Hull et al. (2012), who pointed out more CML was found in pork
strips (0.61 mg/100 g) than in chicken strips (0.51 mg/100 g) and
beef steak (0.42 mg/100 g).
The inconsistent results may be due
to the different conditions of the raw samples (such as the thickness
of meat), the cooking utensils, and the degree of doneness.
We compared the results in different degrees of doneness of
fried beef and pork samples (Table 5).
For the beef samples, the
CML content increased significantly (p < 0.05) with increasing
degree-of-doneness from medium to well done (internal temperature
from 63 to 71 C) both in cooking temperature of 204 C (from
10.15 to 20.03 lg/g) and 160 C (from 10.52 to 16.30 lg/g).
We did
not found any dramatic differences for other change of the degree
of doneness of cooked samples (p > 0.05).
In pork samples, the CML
levels increased significantly (p < 0.05) with rising the internal
temperature from 63 to 71 C both in cooking temperature of
204 C (from 13.29 to 17.53 lg/g) and 160 C (from 8.84 to17.44 lg/g).