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Physico-chemical and antilisterial properties of nisin-incorporated chitosan/carboxymethyl chitosan films

Zimet, Patricia, Mombrú, Álvaro W., Mombrú, Dominique, Castro, Analía, Villanueva, Juan Pablo, Pardo, Helena, Rufo, Caterina
Carbohydrate polymers 2019 v.219 pp. 334-343
Listeria monocytogenes, antibacterial properties, biopolymers, chitosan, composite films, composite materials, food safety, microstructure, nisin, packaging, physicochemical properties
The objective of this work was to investigate the effect of the addition of carboxymethyl chitosan on the structural properties and antilisterial activity of nisin-incorporated chitosan films. Chitosan and carboxymethyl chitosan solutions were prepared with different mass ratios and bacteriocin nisin was added (0, 1000 and 6000 IU/ml). Filmogenic solutions were cast, dried and their physico-chemical and antimicrobial properties were investigated. For the same chitosan/carboxymethyl chitosan mass ratio, the addition of NIS at 6000 IU/ml led to changes in the macro- and microstructure, as well as in physico-chemical properties of films. On the other hand, carboxymethyl chitosan had a plasticizing effect and enhanced the distribution of the bacteriocin within the biopolymer matrix. Moreover, nisin-incorporated blend films of chitosan and carboxymethyl chitosan were more effective against Listeria monocytogenes than their pure chitosan counterparts. This study showed that different formulations of nisin-incorporated composite films of chitosan and carboxymethyl chitosan may provide options for developing bioactive packaging to improve food safety.