POTASSIUM SORBATE PERMEABILITY of METHYLCELLULOSE and HYDROXYPROPYL METHYLCELLULOSE MULTI-LAYER FILMS

Abstract

Spoilage by microorganisms growing on food surfaces is the shelf-life limiting factor for many food products. Previous publications have shown that this shelf-life limitation can be overcome by edible coatings lowering the diffusion rate into the food of antimicrobial agents applied on food surfaces. A permeability cell has been used to evaluate the potassium sorbate barrier properties of polysaccharide based films. In this paper we examine the effect of film formation technique and film formulation on the permeability rate of methyl- and hydroxy-propyl methyl cellulose based films. Permeability constant determinations ranging from 10⁻⁹ to 10¹¹ (mg/s cm²)(cm)/(mg/cm³) indicate that surface resistance to microbial growth could be enhanced significantly. Scanning electron microscopy examinations showed that films were of uniform thickness. Morphological differences between films were consistent with permeability measurements.