Differentiation between fresh and thawed chicken meats

Adulteration of fresh meat and its possible substitution with frozen and thawed meat represents a problem, since thawed meat has not only lower sensory qualities than fresh meat but also a lower price. Commercial enzymatic kits seem to be a solution to reveal such unfair practises and were applied to detect the activity of specific enzymes, citrate synthase, mitochondrial enzymes that are released from the organelles destroyed by frost. We determined, whether the meat of slaughtered chicken was fresh or frozen/thawed, and to provide convincing results. The absolute results vary with the type of meat and depend on the enzyme used. However, the enzyme activity in the exudates of frozen/thawed meat is always higher than in fresh meat. This value further increases with each subsequent freezing cycle. The determination of citrate synthase activity was done only in the exudate released from the examined meat samples. However, to determine the enzymes activity directly in unpacked meat, which have not released any exudate, is the subject of further research.