Application of chitosan coating with oregano essential oil on dry fermented sausage

Abstract

Chitosan film was produced from a highly viscous chitosan solution in acetic acid. Oregano essential oil was added to the film-forming solution, before casting it on a Petri dish. Film mechanical properties (thickness, tensile strength and elongation at break) and barrier properties (water vapour and oxygen permeability) were investigated. The film proved to be strong but brittle with good barrier properties to oxygen and poor barrier properties to water vapour. In second experiment, traditional dry fermented sausage "Petrovská klobása" (label of geographical origin) was coated with chitosan-oregano film-forming solution and stored in a chamber with controlled temperature (15 °C) and relative humidity (75%) for five months. Analyses of moisture content, colour, lipid oxidation as well as sensory analysis of taste and smell were conducted before coating and on 150th day of storage. Coating the sausage with chitosan film slowed down the moisture loss and retarded lipid oxidation, while there was no change in colour of the sausage. Coated sausage obtained better results from sensory evaluation of taste and smell. Results are encouraging for further optimization of natural active packaging as a way of preservation of "Petrovská klobása" sausage. © 2012 VÚP Food Research Institute, Bratislava.