Chitosan coatings enriched with active shrimp waste for shrimp preservation

An active coating solution composed of chitosan (Ch) and a shrimp protein-lipid concentrate (PCc), both obtained from Litopenaeus vannamei processing wastes, was applied to preserve shrimp during chilled storage. The addition of PCc increased the antioxidant capacity of the Ch coating, yielding a lower-viscosity mixture which, however, was viscous enough to adhere to the shrimp while maintaining its activity. The shrimp storage trial showed that the Ch coatings, especially when enriched with PCc (Ch-PCc), delayed microbial growth, mainly by extending the lag phase. Pseudomonas spp. appeared to be the predominant bacteria in the microbiota. H2S-producing organisms and luminescent colonies were especially sensitive to this active coating, with inhibition greater than 4 and 2 log cycle respectively, while the growth of lactic acid bacteria was not favored. The Ch-PCc coating delayed the onset of melanosis and did not confer any sensorially detectable color, taste or odor. It therefore shows promise as a means to improve the quality of shrimp during cold storage.