POTENTIAL OF CHITOSAN-ALGINATE EDIBLE FILMS AS PACKAGING FOR FISH MEAT

Consumers, increasingly aware and informed, tend to demand safe products with proven quality, obtained from good manufacturing and risk control practices. In this context, research has been carried out aimed at replacing synthetic additives with more natural elements, less harmful to consumer health and the environment, whether chemical or microbiological changes. Some animal products like fishs are highly perishable foods, susceptible to rapid microbiological deterioration during storage. In this way, this work aims to develop active chitosan/alginate films incorporated with zinc oxide (ZnO) nanoparticles, aiming to provide an alternative for preserving and increasing the fish shelf life. Films were produced by casting. The polymer concentration in the filmogenic solutions was 1.5%w/v in the following proportions of alginate:chitosan: 100:0; 25:75; 50:50; 75:25 and 0:100. Chitosan solutions were prepared in 1%v/v aqueous acetic acid under magnetic stirring. The alginate was dissolved in distilled water at 60°C under mechanical agitation at 6,500 rpm. Thereafter, a crosslinking with calcium chloride at 1.0% w/w was performed. In all polymeric solutions, 30%w/w glycerol was added. The polymer solutions were poured in an acrylic plate and dried at 35°C for 48 h. The films were characterized regarding chemical, mechanical and barrier properties. All the evaluated formulations resulted in non-rigid and homogeneous films. Alginate and chitosan composite films were less transparent than the single films. Chitosan films were less water soluble than the alginate ones. Films with 100% alginate were completely water-soluble. The sorption degree was in line with the solubility results, i.e., the higher the proportion of chitosan, the lower the sorption degree. Elongation and tensile strength values ranged from 3.67 to 17.87% and 16.10 to 37.87 MPa, respectively. It was observed that the increase in alginate concentration led to an increase in the tensile strength and a reduction in elongation at break. Overall, films produced with more than 75% chitosan concentration showed better potential barrier and mechanical properties, mainly low water solubility and higher elongation at break, being suitable for use in formulations intended to produce edible films. It is expected that films with a higher concentration of chitosan have good potential to conduct the study of films incorporated with ZnO nanoparticles.