In-vitro protein digestibility, total mineral and mineral bioavailability of periwinkle (rough and smooth), clam, whelk, and oyster were evaluated. Total ash content of clams and oysters were 2.87% and 2.92%, respectively. These value were significantly (p<0.05) higher than those of periwinkle (rough and smooth) and whelks. Percentage crude protein ranged from 12.01 - 18.84% with oyster and clams given significantly (p<0.05) higher values. Protein digestibility of the shellfish were 11.90, 8.62, 16.75, 16.64 and 13.88% for periwinkle rough, smooth, whelk, oyster and clam, respectively, with oyster and whelk showing significantly (p<0.05) higher value. A total of six essential minerals: Iron, calcium, magnesium, phosphorus, potassium, and sodium were determined. Potassium was significantly (p<0.05) higher in clam (1286.00 mg/100g) and low in periwinkle smooth (618.90 mg/100g). Whelk was significantly high in zinc and magnesium with values of 23.66 mg/100g and 721.60 mg/100g, respectively. Significantly (p<0.05) higher fraction of soluble Na (343.30mg/100g), K (1040.00 mg/100g), Fe (14.50 mg/100g) and Ca (185.60 mg/100g) were noticed in oyster, clam, periwinkle rough and periwinkle smooth, respectively. Whelk was significantly higher in soluble Zn (8.95 mg/100g) and Mg (718.00 mg/100g). Total calcium was found to be high in whelk (709.80 mg/100g) but only 58.80% was soluble after digestion with periwinkle rough recording the highest bioavailable calcium (84.30%).
The knowledge of the mineral bioavailability, protein content and digestibility of some selected shellfish can give indication of the nutritional advantage of shellfish in fortifying carbohydrate based diets as a step towards alleviating the problem of protein energy malnutrition. Knowledge from this study presents shellfish as source of high quality protein with all the dietary essential amino acids and essential minerals necessary for maintenance and growth of the human body.
Shellfish, Mineral bioavailability, Protein digestibility