Proximate and Mineral Composition of Raw and Boiled Tympanotonus fuscatus var. radula Sold in Markets in Nasarawa State, Nigeria

Abstract

Tympanotonus fuscatus var. radula are invertebrates commonly consumed in Nigeria and valued for their medicinal, nutritional and economic importance. In Nigeria, some people use the shelled Tympanotonus fuscatus var. radula periwinkle for cooking while others prefer the unshelled (flesh). This study investigated the proximate and mineral composition of raw and boiled T. fuscatus var. radula sold in selected markets in Nasarawa State, Nigeria. Raw samples of Tympanotonus fuscatus var. radula were bought from Keffi, Masaka, and Orange markets. The proximate composition was determined using standard analytical methods. Mineral analysis was determined by Atomic absorption spectrophotometry. Raw periwinkles had a high moisture content ranging from 68.76% to 70.31%, and protein contents ranging from 48.10% to 49.60%, with low lipid values (0.33% –1.62%). Boiling the periwinkles under laboratory conditions of 100℃ for 10 minutes gave moderate reductions in protein content (44.10% –46.00%) and mineral concentrations, as well as variable changes in moisture level (59.42% –69.00%). The result showed that raw and boiled samples with shells and without shells (flesh) have adequate crude protein, crude ash and crude fibre. It is low in crude lipid and carbohydrate. This makes it suitable as a food supplement and a good source of high animal protein.  The potassium, manganese, magnesium, zinc and iron values did not exceed the set standard safe for human consumption. The raw periwinkles contained appreciable levels of calcium (43.22–49.51 mg/100 g), magnesium (141.62–169.78 mg/100 g), potassium (22.22–39.64 mg/100 g), and iron (6.25–14.51 mg/100 g), insignificant reduction in value after boiling, especially for calcium and potassium. The varying values obtained from the different markets could be attributed to the effect of environmental conditions, such as harvesting methods and post-harvest handling. The periwinkle T. fuscatus var. radula is nutrient packed, low-fat food with the ability to improve dietary protein and micronutrient intake. The result of Investigation showcases the importance of processing in determining nutritional quality. Tympanotonus fuscatus var radula is especially recommended for consumption by diabetics and people with fat related issues.