ABSTRACT

The efficiency of depuration on total heterotrophic fungi and nutritional composition in periwinkle {Tympanotonus fuscatus) was evaluated in this study. The total heterotrophic fungi counts at different time intervals (0 h, 24 h, 48 h, 72 h and 96 h) of depuration were 2.43 x 103 cfu/g, 1.84 x io3 cfu/g, 0.00 x io3 cfu/g, 0.00 x io3 cfu/g and 1.65 x 103 cfu/g respectively has significant difference (P<0.05). The fecal coliform bacteria count was not detected in this study. The proximate composition ofthe depurated periwinkles soft tissues was assessed. The crude protein, moisture and ash contents of 0 h, 48 h and 96 h of depurated soft tissues increased from 14.41 to 14.72%; 81.41 to 82.28% and 1.05 to 1.13% respectively while the fat, dry matter contents and carbohydrate decreased among all samples 0.64 to 0.45%; 18.59 to 17.73% and 2.49 to 1.43%. The results show that there was significant difference (P<0.05) in the moisture, dry matter, ash, and fat contents except for protein and carbohydrate (48 h and 96 h) has no significant difference (P>0.05). The periwinkle soft tissues in depuration tank were taken at time interval (0 h and 96 h) of depuration was analyzed for heavy metals concentration (Chromium, Cadmium and Lead). The initial metal concentration (0 h) was higher (0.97 mg/1) in the whole soft tissues for Cadmium. After 96 h depuration, Cadmium was significantly reduced to 0.11 mg/L Cr and Pb were not detected in this study due to seasonal fluctuation. The physicochemical attributes of periwinkles subjected to depuration process on daily basis for 3 days (0 h, 48 h, and 96 h) in tap water were determined. Salinity ranged from 4.2 to 5.71 mg/1, dissolved oxygen (4.82 to 5.89 mg/1), temperature (28.0 to 27.8°C), and pH (6.80 to 7.77). There was progressive increase in the parameters except for turbidity which was not detected. The act of depuration was found to be beneficial as depuration prior to consumption increased nutritional contents and reduced heavy metals which are toxic to the human body and microbe’s content on consumption