Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer reviewed journal
Publication Acceptance Date: 1/24/2010
Publication Date: 3/24/2010
Citation: Bilbao-Sainz, C., Avena Bustillos, R.D., Wood, D.F., Williams, T.G., Mchugh, T.H. 2010. Composite edible films based on hydroxypropyl methyl cellulose reinforced with microcrystalline cellulose nanoparticles. Journal of Agricultural and Food Chemistry. 58(6):3753-60. Interpretive Summary: One of the main purposes of using edible films in the food industry is to prevent water migration between the product and its surroundings as well as between different areas of the same product. HPMC is a cellulose derivative capable of forming edible films with good quality properties. However, the disadvantage of this compound is its affinity for water which makes it unsuitable as a moisture barrier. This study shows that the moisture barrier properties of the HPMC films can be improved by adding lipid-coated microcrystalline cellulose at the nano scale since the lipid coating reduce the affinity of the HPMC films for water.
Technical Abstract: It has been stated that hydroxypropyl methyl cellulose (HPMC) based films have promising applications in the food industry because of their environmental appeal, low cost, flexibility and transparency. Nevertheless, their mechanical and moisture barrier properties should be improved. The aim of this work was to enhance these properties by reinforcing the films with microcrystalline cellulose (MCC) at the nano scale level. Three sizes of MCC nanoparticles were incorporated into HPMC edible films at different concentrations. Identical MCC nanoparticles were lipid coated (LC) prior to casting into HPMC/LC-MCC composite films. The films were examined for mechanical and moisture barrier properties verifying how the addition of cellulose nanoparticles affected the water affinities (water sorption/desorption isotherms) and the diffusion coefficients. The expected reinforcing effect of the MCC was observed: HPMC/MCC and HPMC/LC-MCC films showed up to 53% and 48% increase, respectively, in tensile strength values in comparison with unfilled HPMC films. Furthermore, addition of unmodified MCC nanoparticles reduced the moisture permeability up to 40% and the use of LC-MCC reduced this value up to 50%. Water vapor permeability was mainly influenced by the differences in water solubility of different composite films since, in spite of the increase in water diffusivity values with the incorporation of MCC to HPMC films, better moisture barrier properties were achieved for HPMC/MCC and HPMC/LC-MCC composite films than for HPMC films.