Kinetics and thermodynamics of thermal inactivation of the antimicrobial peptide cerein 8A

Optimization of thermal processes relies on adequate degradation kinetic models to warrant food safety and quality. The knowledge on thermal inactivation kinetics of bacteriocins is necessary to allow their adequate use as natural biopreservatives in the food industry. In this work, the kinetics of thermal inactivation was studied for the previously characterized bacteriocin cerein 8A. Samples of cerein 8A were treated at different time-temperature combinations in the range of 0-30 min and 70-82 degrees C and the thermodynamic and kinetic parameters for bacteriocin inactivation were calculated. Results showed that inactivation followed a first-order reaction with k-values between 0.059 min(-1) and 0.235 min(-1). D- and k-values decreased and increased, respectively, with increasing temperature, indicating a faster bacteriocin inactivation at higher temperatures. Results suggest that cerein 8A is a relatively thermostable bacteriocin with a z-value of 21.98 degrees C and E-a of 105.7 kJ mol(-1). (C) 2008 Elsevier Ltd. All rights reserved.