Acid-free chitosan coatings for cheese

Chitosan is a biodegradable polysaccharide extracted from several natural sources extensively studied in food packaging. However, conventional wet-processing in acetic acid hinders its applications as it may negatively affect the organoleptic properties of the products. In this study, we propose a novel procedure for developing chitosan coatings and films that eliminates the need for organic acid processing. Chitosan powders are first dissolved in HCl and neutralized to obtain a gel, then carbonic acid is used to dissolve the material in water by producing in situ CO2 gas. The reversible nature of water carbonation results in the easy removal of acid residues originating in an acid-free chitosan system. Chitosan films and coating performances have been compared with a state-of-the-art chitosan system as well as a polymeric coating employed in the dairy industry on Provolone cheese as a food model. Preliminary characterization includes water stability, barrier properties, rheology assessment, SEM analysis, and evaluation of optical transparency. Moreover, we evaluate the performance of the developed coatings on cheese for a storage time of up to 14 days, performing textural profile analysis and measuring the samples’ weight loss. This work demonstrates the advantages of this novel chitosan formulation in addressing key issues related to food quality and safety, thereby opening new possibilities for effective application in food packaging.