Biodegradable Active Films to Improve the Preservation of Regional Cheese During Refrigerated Storage

The aim of this work was to demonstrate that the use of biodegradable films activated with natamycin is effective for the preservation of regional cheeses. For this, starch and amylose films were prepared using only water as a plasticizer, gelatinizing at temperatures of 120 degrees C, and using two levels of antimicrobial. Moisture content, water solubility, WVP, mechanical properties, and biodegradability of all films were measured. The films obtained were ductile and homogeneous, and the active agent did not significantly change their mechanical properties, biodegradability, or solubility; however, it did reduce the WVP values, but this did not condition the applicability as a coating in any case. Visual observation, weight loss, antimicrobial migration, and microbiological analyses were carried out on cheese wrapped with films with and without natamycin and stored under different humidity and temperature conditions. Visual inspection showed the development of molds and yeasts on the surface of control cheeses and those covered with films without antimicrobial, while no developments were evident in the activated film. Weight loss was reduced by 5% for high humidity storage with the application of films, and for the levels tested, concentrations of natamycin were not detected in cheese mass. With the starch film and 10 mg/dm(2) of natamycin (M6), it was possible to delay the growth of molds and yeasts (1.05 logarithmic cycle reduction) and psychrophilic bacteria for the 30 days of study, allowing a better-quality preservation of food in the storage, using an eco-friendly and easy-to-develop material.

Automated summary

The aim of this study was to demonstrate the effectiveness of biodegradable films activated with natamycin for preserving regional cheeses. Starch and amylose films were prepared using water as a plasticizer and different concentrations of antimicrobial. The films exhibited good mechanical properties and biodegradability, and the addition of natamycin reduced water vapor permeability without compromising their applicability as coatings. Cheese wrapped with the activated films showed no development of molds and yeasts, and weight loss was reduced under high humidity storage conditions. The use of starch films with 10 mg/dm(2) of natamycin delayed the growth of molds, yeasts, and psychrophilic bacteria, providing better-quality food preservation.