Stability of methylcellulose-based films after being subjected to different conservation and processing temperatures.

Methylcellulose films with and without sorbitol addition were developed. The major objective of this study was to attempt insights into the stability of the methylcellulose-based film properties after having been subjected to freezing, storage or a combination of both procedures. The importance of the sorbitol concentration and process temperature was also to be elucidated. As-prepared film solubility decreased at 100 °C, as a result of the methylcellulose thermogelation property when the samples were exposed to high temperatures. By analyzing the film pattern behavior and its properties 0.25% w/v sorbitol concentration turned out to be an inflexion point. The moisture content as well as the mechanical and thermal properties made this fact evident. Moreover the elastic modulus (Ec) and glass transition temperature (Tg) did not undergo significant changes for higher plasticizer concentrations. The methylcellulose film properties remained more stable in the presence of sorbitol, which would act as a protective agent due to its hydrogen bonding capacity. This stability is crucial for film and coating applications in the food industry.