Nutritional and Quality Attributes of Oil From Indian Oil Sardine (Sardinella longiceps) and Mixed Species of Fishes

The quality of fish oil depends primarily on the fish species used for oil manufacturing. There is a growing practice in the industry to use mixed fish species to produce fish oil, as an alternative to polyunsaturated fatty acid (PUFA)–rich fish species, which were largely utilized for dietary purposes. However, there are no studies made yet on the quality attributes of oil from mixed species. The study aims to compare the physical, chemical, and nutritional quality of fish oil extracted from body oil of Indian oil sardine (Sardinella longiceps) and the oil extracted from mixture of fishes like Indian oil sardine, Indian mackerel (Rastrelliger kanagurta), horse mackerel (Megalaspis cordyla), and ribbonfish (Lepturacanthus savala). The oil from Indian oil sardine exhibited lower viscosity (58 cP) and higher moisture content. Iodine value, saponification value, peroxide value, anisidine value, and free fatty acid values were significantly lower for the oil from Indian oil sardine. Palmitic acid was the predominant saturated fatty acid in both the oil samples, whereas docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) contents were the predominant PUFAs. DHA content was 12.66% in sardine oil compared to 14.33% in mixed fish oil. Lipid quality indices (index of thrombogenicity, health-promoting index, unsaturation index, fish lipid quality, polyene index, ratio of hypocholesterolemic to hypercholesterolemic, EPA + DHA, ∑PUFA/SFA, and n-3/n-6 fatty acids) were evaluated for both the oil samples. The study demonstrated that the oil from mixed fish species exhibited comparable nutritional indices to the oil from Indian oil sardine.

Practical Applications: The study addresses a major prevailing problem of excessive fishing pressure on the Indian oil sardine fishery as it sustains the fishmeal and oil industry. The use of Indian oil sardine alone for oil extraction leads to hampering the supply of this fish for human consumption. Utilizing mixed fish species for oil extraction is expected to limit the burden on Indian oil sardine fishery. Fish oil extracted from mixed species of fishes was determined to be healthier in terms of fatty acid profile, including omega-3 fatty acids and lipid quality indices. This strategy offers a sustainable solution to fulfill the nutritional requirements of the growing population as well as helps in reducing fish waste-related problem if the discards are also used for fish oil and fishmeal manufacturing. Outcome of the study is in line with the UNSDGs 3, 9, 12, and 14.