Beef quality monitoring using immobilization lipase on modified polypropylene non-woven fabric based on time-temperature indicator

A lipase-based time-temperature indicator (TTI) was developed via the immobilization of lipase on polyethylene imine/glutaraldehyde/polypropylene non-woven fabric for the catalytic hydrolysis of glyceryl triacetate. pH of the reaction system gradually decreased and the color changed from green to orange or salmon pink. Four TTIs were selected by changing the concentration of glyceryl triacetate methanolic solution, the concentration of lipase-phosphate buffer solution, and the amount of phosphate buffer added, storing at 5-25 degrees C and measuring the coloration difference every 24 h. The Arrhenius activation energy (Ea) of obtained TTIs was calculated as 26.28, 47.98, 38.87, and 42.00 kJ/mol. For the application of TTIs to fresh beef monitoring, the kinetic properties of beef were studied and an Ea value of 37.60 kJ/mol was obtained. The similarity of these Ea shows accuracy in the prediction of beef quality with TTI color development.