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

Abstract

Abstract 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 m2/g). The ceZL exhibited a high relative activity within 4 °C – 40 °C and the activation energy (Ea) of coloration approached 26.28 kJ/moL for 80 μg/cm2 of ceZL-immobilized laccase. In dynamic temperature response experiments of ceZL using intermittent temperature changes between 4 °C and 25 °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 °C when 25 or 8 μg/cm2 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.