Effect of essential oils and homogenization conditions on properties of chitosan-based films

[EN] The influence of essential oil type (basil and thyme), its content and the homogenization treatment on the physical properties of chitosan-based film-forming dispersions and edible films was studied. Two homogenization treatments were applied, without (H1) and with (H2) microfluidization (MF) at 165 MPa. H2 emulsions showed the smallest particle size with the highest zeta-potential and the lowest viscosity. Composite films with essential oils were softer, less rigid and more stretchable than pure CH films. MF intensified these changes. H2 films showed micro-cracks due to the weakening of the polymer chain interaction forces when oils are present, which affected their mechanical behaviour. MF increased WVP of pure CH films while oil incorporation was only effective to reduce WVP when they were incorporated at the lowest ratio and when high pressure was used in the homogenization of the film-forming dispersion. Gloss was reduced by the essential oil addition, whereas MF tended to yield glossier films.The authors acknowledge the financial support from the Spanish Ministerio de Educacion y Ciencia through Project AGL2010-20694, from Universidad Politecnica de Valencia through Project PAID-06-09-2834 and from Conselleria de Empresa, Universidad y Ciencia (Project GV/2010/082). Authors also thank Manuel Planes, Jose Luis Moya and Mercedes Tabernero of the UPV Electronic Microscopy Service for their assistance in the use of the SEM.Bonilla Lagos, MJ.; Atarés Huerta, LM.; Vargas, M.; Chiralt, A. (2012). Effect of essential oils and homogenization conditions on properties of chitosan-based films. Food Hydrocolloids. 26(1):9-16. doi:10.1016/j.foodhyd.2011.03.015S91626