Abstract:

Out of 17 preservatives, previously found to be highly effective against Pseudomonas using a plate culture system, the
preservatives having little influence on the color, taste, morphology or elasticity of fresh grass carp belly were screened by sensory
evaluation. Results suggested that after treatment with gallic acid, citric acid, tannic acid, trimethyl phosphate, polylysine or phytic
acid, the color of fish belly remained normal, the flavor was maintained and no negative impact on morphology or elasticity was
seen. The quality change of grass carp belly with preservative treatments during cold storage was assessed. A first-order model
describing microbial growth was constructed based on the microbial growth curve. The bacteriostatic activity of preservatives was
quantitated by model parameters. This study showed that ε-polylysine was the best preservative for grass carp belly. It had less
impact on the quality of grass carp belly and exhibited stronger bacteriostatic activity than other preservatives. The shelf life of
fresh grass carp with ε-polylysine treatment and modified atmosphere packaging (50% CO2 + 50% N2) when stored at 4 ℃ was 13
days. In conclusion treatment with ε-polylysine can help maintain the shelf life of grass carp.

Key words: fresh-cut grass carp, antistaling agent, shelf life, ε-polylysine