Physico-chemical, microbiological and organoleptic assessment for the stored frozen products of tuna

The current study aimed to evaluate the physico-chemical, microbiological and organoleptic characteristics of proposed tuna (Thunnus thynnus) products during the storage under freezing conditions. Tuna products of burger, nuggets and fingers were prepared and stored at -18°C for six months. The above-mentioned characteristics were measured every two weeks as a time interval during the storage period. The moisture content significantly decreased over the storage time (3.11±0.83 g every two weeks). As a result, at the end of storage time (6 weeks), the loosing ratios in moisture content for burger, nuggets and fingers were 15.87, 16.03 and 15.84 (%), respectively. Heavy metals content in tuna was arranged in a descending order as iron> copper> lead> cadmium> mercury, with values being 27.7, 6.30, 2.035, 1.214, and 0.547 mg/kg fresh weight, respectively. There were no significant differences observed among the levels of the toxic metals (Hg, Pb and Cd) in raw tuna meat and its products. The results of microbiological analysis revealed that the total bacterial count and numbers of Salmonella sp. and E. coli were decreased over time under freezing condition. Except for firmness and gumminess, the texture characteristics of tuna products showed no significant changes during the storage period. The results concluded the stability and safety of tuna burger, nuggets and fingers under freezing conditions besides the high acceptability for these products between the consumers.