Development of immobilized laccase-based time temperature indicator by electrospinning zein fiber

To increase the stability of enzymatic time-temperature indicator (TTI), laccase was immobilized on the electrospun zein fiber (ceZL) with high specific surface area (11.579 m(2)/g). The ceZL exhibited a high relative activity within 4 degrees C - 40 degrees C and the activation energy (Ea) of coloration approached 26.28 kJ/moL for 80 mu g/cm(2) of ceZL-immobilized laccase. In dynamic temperature response experiments of ceZL using intermittent temperature changes between 4 degrees C and 25 degrees C, irreversible inactivation did not occur, indicating the desirable tolerance and sensitivity of ceZL to temperature alterations. Approximately 6 or 26 days was required to reach the endpoint of coloration at 4 degrees C when 25 or 8 mu g/cm(2) of laccase was immobilized on ceZL, respectively. The regression equation derived from kinetic analysis was conducted and could be further utilized to design a suitable TTI to monitor food quality according to the color change of TTI by using ceZL.