Smoking Methods and their Effects on Nutritional Value of African Catfish (Clarias gariepinus)

Abstract

African catfish (Clarias gariepinus) is very popular with fish farmers and consumers, and commands a very high commercial value in Nigeria markets. The fresh fish sample collected from the fish farmer was smoked in a smoking kiln using sawdust, rice bran and melon husk while electric oven was used as the control. In the study proximate, mineral and amino acid compositions of the smoked fish samples were evaluated using standard analytical techniques. The crude protein content of the smoked fish samples ranged from 15.18% in sawdust heat treatment to 63.23% in electric oven heat source with CV% of 10.68 while crude fat range values were 9.47 – 16.44% (CV% = 18.80). The most highly concentrated mineral was sodium (7.00 – 9.95 mg/100g sample) and strictly followed by magnesium (5.45 – 7.45 mg/100g sample). Lead and cadmium were not at the detectable range of AAS. The total essential amino acid (TEAA) with histidine in the smoked fish samples ranged from 40.25 g/100g crude protein in rice bran to 70.09 g/100g protein in sawdust heat sources while lysine had the highest concentrations (7.02 – 7.78 g/100g protein). The calculated isoelectric point (pI) and predicted protein efficiency ratio (P–PER) were (4.99 – 6.91) and (2.30 – 2.52), respectively while first limiting amino acid (LAA) was isoleucine for electric oven and sawdust heat sources, and valine for melon husk and rice bran smoking. The number of essential amino acids where supplementation may be required in the smoked fish samples using four different heat sources was three each. Generally, all the fish samples were found to be good sources of essential minerals and amino acids.