Effect of Chitosan Edible Coating on the Biochemical and Physical Characteristics of Carp Fillet (Cyprinus carpio) Stored at −18°C

The effect of an edible coating (EC) with 1.5% chitosan as an additive, on common carp (Cyprinus carpio) fillet, was determined evaluating the biochemical, physicochemical, textural, microbiological, and nutritional characteristics periodically during its storage in the freezer (−18°C), observing a decrease in the rate of biochemical reactions related to degradation (p < 0.05), hydroperoxides content (HPC) (0.8324 nM hydroperoxides/mg of protein versus 0.5540 nM/mg with regard to the EC sample), as well as protein carbonyl content (PCC) (0.5860 nM versus 0.4743 nM of reactive carbonyl groups/mg of protein of noncoated material), keeping properties for a longer period of time, and a lower protein solubility (7.8 mg of supernatant protein/mg of total protein versus 6.8 mg/mg) and less loss of moisture (8% less, with regard to EC); for the nutritional characteristics of the fillet, lysine is the limiting aminoacid in the sample without EC, while leucine is the limiting aminoacid for the EC sample. According to microbial growth, the count was 2.2 × 10(5) CFU/g of sample in mesophiles versus 4.7 × 10(4) in the EC sample. The results indicate that the use of EC added with chitosan maintains the quality of the product regarding lipid and protein oxidation until fourth month of storage, maintaining moisture content without variation for at least 3 months, and inhibits microbial growth up to 2 logarithmic units, during five months of frozen storage.