Inactivation of pectic lyases by light exposure in model systems and fresh-cut apple
Lara Manzocco, Andrea Dri and Barbara Quarta
Innovative Food Science & Emerging Technologies, Volume 10, Issue 4, October 2009, Pages 500-505
2009
บทคัดย่อ
UV-C light exposure caused the inactivation of pectin lyases from Aspergillusjaponicus and pectate lyase from apple under non-thermal conditions. Samples exposed to 20 W m−2UV-C light showed DL values, defined as the time needed for 90% enzyme activity reduction, around 20 min. However, an initial activation phase was observed for fungin pectin lyase, while UV-C light resistant forms of pectate lyase were identified in apple. Lyase inactivation occurred as a consequence of enzyme cleavage into fragments without catalytic activity having MW around 5 kDa. Fresh-cut apple slices exposed for a few minutes to UV-C light resulted significantly firmer than the untreated ones during 4 days of refrigerated storage, reasonably due to the decrease in activity of both endogenous and microbial lyases on the surface of the wound apple tissue.