Chitosan as an edible film for protection of seafood quality

• Main Author: Yatiyana Vidana Arachchilage, Janak Kamil
• Format: Thesis
• Language: English
• Published: Memorial University of Newfoundland 2000
• Subjects: atlantic cod; Gadus morhua; Snow crab
• Online Access: https://research.library.mun.ca/9082/; https://research.library.mun.ca/9082/1/Kamil_YatiyanaVidanaArachchilageJanak.pdf

Preservation of seafood quality against oxidation of highly unsaturated lipids, autolysis reactions and microbial activities is important. Chitosan, a deacetylated form of chitin, has been identified as a versatile biopolymer for a broad range of food applications. However, very little information is available about the use of chitosan as an edible coating material for preservation of seafood quality and virtually nothing is known regarding the effect of viscosity of chitosan on its preservative efficacy for seafood. Effect of chitosan coating for extension of shelf-life of two different fish species, Atlantic cod (Gadus morhua) as a lean fish, and herring (Clupea harengus) as a fatty fish, was evaluated during a 12-days storage at refrigerated temperature (4 ± 1°C). Three chitosan preparations from snow crab (Chinoecetes opilio) processing wastes, differing in viscosities and molecular weights, were prepared and used in this study. The apparent viscosity of chitosans was dependent on the deacetylation time of their chitin precursors and were 14, 57 and 360 cP for samples prepared over a 20, 10 and 4 h period, respectively. -- Prepared chitosan samples were used as edible coating material on the surface of the fish muscle and the quality of the coated samples were monitored. This was achieved by monitoring relative moisture loss (%) and peroxide value (PV), conjugated dienes (CD), 2-thiobarbituric acid-reactive substances (TBARS) and headspace (HS) volatiles, all which are related to lipid oxidation. Furthermore, total volatile basic nitrogen (TVB-N), trimethylamine (TMA) and hypoxanthine (Hx), which are related to chemical spoilage, as well as total plate count (TPC) related to microbial spoilage were monitored. A significant (p ≤ 0.05) reduction in relative moisture loss, by 37, 29, 29, 40, and 32%, over that of uncoated cod samples was observed for those coated with 360 cP chitosan after 4, 6, 8, 10, and 12 days of storage, respectively. Chitosan coating significantly (p ≤ 0.05) reduced lipid oxidation, ...