Effect of irradiated chitosan on the rancidity of radiation-processed lamb meat

We report here the production of irradiated chitosan and its novel use as a natural antioxidant for minimising lipid peroxidation of radiation-processed lamb meat. Antioxidant activity of chitosan isolated from shrimp waste was determined by the beta-carotene bleaching assay and 1,1-Diphenyl-2-picrylhydrazyl (DPPH) scavenging activity. Irradiation of chitosan at 25 kGy dose of gamma radiation resulted in a six-fold increase in its antioxidant activity as compared to the non-irradiated chitosan as measured by DPPH assay. Similarly the reducing power of irradiated chitosan was 6-fold greater than autoclaved chitosan. The suitability of irradiated chitosan for controlling lipid oxidation of radiation-processed meat was also investigated. Irradiated chitosan when added to meat before radiation processing was found to be more effective in minimising lipid perioxidation than non-irradiated chitosan as measured by TBA number and carbonyl content. TBA values of irradiated meat containing irradiated chitosan decreased by 88% (leg) and 54% (rib) as compared to the corresponding sample without chitosan. Further development of post-processing rancidity was reduced by 39% (leg) and 59% (rib) in the samples treated with chitosan as compared to non-treated controls even after a week of storage at 0–3°C.