Patent ID: 7736866

Claim:
A time temperature indicator for indicating temperature change over time, comprising an immobilized enzyme, wherein the enzyme is an amidase, a lipase, a glycosylase, a carboxylic esterase or an ether hydrolase, and a substrate of the enzyme, said substrate being a pigment precursor selected from the group consisting of (a) a compound of general formula (I) wherein R is an unsubstituted or substituted, aliphatic or aromatic residue and (b) a compound of general formula (II) wherein wherein R″ is an unsubstituted or substituted, aliphatic or aromatic residue or wherein the reaction of the substrate catalyzed by the enzyme produces a reaction product in a time and temperature dependent manner and wherein the formation of the reaction product can be detected by monitoring a physical characteristic of the substrate and/or the product which is linked to its concentration.