Ash Contents of Trace Metals and Concentration of Oil in the Fresh Water Fish, Notopterus notopterus

Abstract

The ash content refers to the inorganic residue remaining by ignition or complete oxidation is a part of proximate analysis for nutritional evaluation and it is an important quality attribute for some ingredients such as minerals. The ash contents of trace macro, micro metals and whole-body oil concentration was determined in the locally available fresh water fish, Notopterus notopterus. This fish is available in large numbers in the aquatic bodies of Kalaburagi and is being consumed as food fish by local population. The ash content was determined by dry weight method and the contents of trace metals determined in the ash by processing for Atomic Absorption spectrometry (AAS). The total body oil concentration was analyzed by boiling the fish sample and oil was extracted. The total ash was found to be 10g/100 gm of fish and the trace metals in the ash was chromium, zinc, iron and lead, whereas copper, mercury and cadmium were not detected in the ash. The oil concentration in whole fish was at 2.85 ml. The free fatty acids (FFA) and acid value of the value of the oil was determined and found to be 1.78 (less than 2) and found suitable for edible purpose. The results indicate that the fish, Notopterus notopterus has lesser amount of trace metals and the fish body oil has been extracted with less quantity , may be because of lean body of the fish and it is found to be not a fatty fish. Since the fish has necessary nutritional compositions and this fish can be considered as food fish in the local area.