Freshness Index (K Value)

Decomposition of ATP is an important biochemical postmorten change in muscles of fish and shellfish. During this process, ATP, ADP, and AMP decompose quickly to form a build-up of inosine and hypoxanthine. As this corresponds well with a decline in freshness, the ratio of the quantity of inosine and hypoxanthine to the total quantity of ATP and related substances is called the K value and used as an index representing freshness of fish meat.

Sample : ATP, ADP, AMP, IMP, Hypoxanthine, Inosine