Optimization of chitosan biofilm properties by addition of caraway essential oil and beeswax

Caraway essential oil and beeswax were added to chitosan in an attempt to design natural, biodegradable, bioactive (antioxidant and antimicrobial) packaging film with good barrier properties toward water vapor, as well as air oxygen. Results suggest that beeswax addition negatively affected mechanical properties and oxygen permeability (increased from 6.54 +/- 3.94 cm(3)/(m(2)24hbar) to 1903.17 +/- 94.87 cm(3)/(m(2)24hbar)), but lowered chitosan film sensitivity to ambient humidity, swelling in different pH, water solubility and water vapor transmission rate (decreased from 210.08 +/- 7.76 g/m(2) d to 32.48 +/- 6.79 g/m(2) d). Structural changes were only detected (using FTIR spectrometer) when beeswax was added to the film. Antioxidant activity of chitosan film was detected (28.96%, after 24 h) and it was significantly (p < 0.05) increased by the caraway oil addition (around 80% after 24 h). Produced films were effective antimicrobial agents against Escherichia coli and Staphylococcus aureus and recorded activity originated from chitosan molecule. (C) 2015 Elsevier Ltd. All rights reserved.