Nutritional evaluation of fish scale of selected saline and fresh water fish species

Abstract

Fish scale is the major waste materials of fish having different vital nutrients, proteins, and fatty acids. But unfortunately, it has not been drawn much attention due to want of available researches and information. So, the present research has been emphasized on the exploration of proximate compositions and fatty acid profile in two fresh water fish L. rohita and C. idella as well as saline water fish L. calcarifer and T. ilisha. All the experiments were carried out according to International Organization for Standardization (ISO) and Association of Official Analytical Chemists (AOAC). The individual percentage of fatty acid was identified and quantified, using Gas Chromatography-Flame Ionization Detector (GC-FID) and the prominent percentage of docosanoic acid was found as 25.96 ± 0.05%, 51.74 ± 0.04%, 56.58 ± 0.01%, and 32.88 ± 0.04% in L. rohita, C. idella, L. calcarifer, and T. ilisha, respectively. Besides, among the mono and poly unsaturated fatty acids, palmitoleic acid and linolenic acid were traced in higher amount respectively, in all fish species. The quality of fish scale oil was evaluated using saponification value, iodine value, ester value, acid value, percentage of free fatty acid, and percentage of glycerin that was found as 183.78 ± 0.34 mg KOH/g, 29.93 ± 0.21 mg I2/g, 175.31 ± 0.31 mg KOH/g, and 17.53 ± 0.24 mg KOH/g, in L. rohita, T. ilisha, L. rohita, and L. rohita, respectively. The proximate analyses showed that the maximum percentage of moisture (53.20 ± 0.23%) and lipid (1.42 ± 0.11%) was noticed in L. rohita whistle, the maximum percentage of ash (18.70 ± 0.27%) and protein (32.37 ± 0.26%) was found in T. ilisha. Furthermore, among the different minerals, calcium was found as higher amount than others minerals in all four species.