Active Films and Coatings Based on Propolis Extract and Chitosan: Physicochemical Characterization and Potential Application in Refrigerated Shrimps (litopenaeus Vannamei)

Melanosis is a bio-chemical reaction that reduces the acceptability of refrigerated shrimps. The current research aims to produce and characterize chitosan-based coatings added of propolis extract (PE), as well as to investigate the potential application of these materials to control the melanosis of refrigerated shrimps during storage (9 days). Shrimps are coated with chitosan solutions content different PE concentrations (0%, 5%, 10%, and 20%). Uncoated shrimps and shrimps coated with sodium metabisulfite are also investigated. The incorporation of PE modifies the crystalline structure of chitosan, reducing the water contact angle, and thermal stability of films. Shrimps coated with chitosan-based solutions containing 20% of PE display lower dark points in the cephalothorax and joints region, as well as better weight retention during storage. These results suggest that chitosan-based coatings containing PE can be an eco-friendly alternative to substitute sodium metabisulfite in refrigerated shrimps.