DETERMINATION OF NATURAL FORMALIN LEVEL IN SEA FISH COLLECTED FROM SOUTH-EAST COASTAL AREA OF BANGLADESH

Abstract

Formaldehyde is unethically used by some fishermen and fish vendors to preserve the fish and seafood from microbial spoilage. But this compound is produced from the enzymatic reduction of trimethyamine-N-oxide to formaldehyde and dimethylamine during frozen storage and detected by formaldehyde machine by mobile court and impose fine to local seller for that natural formalin content of fish. The present study was conducted to assess the quantitative analysis of natural formalin level in sea fish collected from south-east coastal area of Bangladesh by Ultra-high performance liquid chromatography (UHPLC) method. Most abundant fish species found in South-east Coastal Area of Bangladesh namely Loitta (Harpadon Nehereus), koral (Lates Calcarifur), Rupchanda (Pampus Chinensis), Hilsha (Tenualosa Ilisha), Poa (Pama Pama) and Maittya (Euthynnus Affinis) were collected from Chittagong (Fishery ghat), Sandwip, Hatiya and Cox’s Bazar. Freshly caught samples were evaluated for determination of formaldehyde concentration in UHPLC. Peak area from the UHPLC for each sample gives the corresponding formaldehyde concentration compare with the calibration curve. Mean formaldehyde content in different fishes collected from different locations of Bangladesh was estimated from the absorbance and molar concentrations of standard curve. From the present experiment it was evident that fishes viz. Loitta (Harpadon Nehereus), koral (Lates Calcarifur), Rupchanda (Pampus Chinensis), Hilsha (Tenualosa Ilisha), Poa (Pama Pama) and Maittya (Euthynnus Affinis) showed a range of 41.5±0.15811 to 54.28±0.54037 mg/kg formaldehyde at initial. After 2 hours the formaldehyde content were found in the ranges of 53.38±0.75961 to 57.18±0.52154 mg/kg. Based on the result of present study, there were significant differences in the concentration of natural formaldehyde between fish samples at initial and after 2 hours of storage at room temperature. The natural formaldehyde concentration of all fish sample except Koral-1 increases with elapsing of time at room temperature. The present study will differentiate the content of natural formaldehyde and adulterated formaldehyde in fish that is produced in fish muscle by enzymatic conversion of trimethylamine oxide breaks into formaldehyde and dimethylamine in equal parts after the fish dies.