Cellulose derivative based active coatings: Effects of nisin and plasticizer on physico-chemical and antimicrobial properties of hydroxypropyl methylcellulose films

Bioactive composite coatings based on hydroxypropyl methylcellulose (HPMC), broad-spectrum food preservative nisin (Nisaplin (R)), and hydrophilic plasticizer glycerol were evaluated for mechanical, barrier (O-2, H2O), transparency and microbiological effectiveness. Incorporation of Nisaplin (R) into cellulose derivative, i.e. HPMC-based films strongly increased the film thickness due to salt crystallization while glycerol had normalized it by homogenous dispersibility. The tensile strength of composite films decreased, however ultimate elongation was increased significantly. The dynamic vapour sorption experimental data fitted by different models had shown lesser values of respective energy constants for composite films. The transparency and water permeability of HPMC films were negatively affected by the additives as an effect individual but conversely as combined effect for film transparency. Film bioactivity demonstrated efficacy against Listeria > Enterococcus > Staphylococcus > Bacillus spp. These cellulose derivative based active films may thus be a key approach towards eradicating post-process contamination of healthy foods. (C) 2010 Elsevier Ltd. All rights reserved.