Lipids from visceral depot fat of Asian seabass (Lates calcarifer): Compositions and storage stability as affected by extraction methods

Abstract

Lipids from Asian seabass visceral depot fat (SVDF) were extracted using different methods including heating in air, heating under vacuum, autoclave and solvent extraction. Lipid extracted by heating under vacuum had the highest yield (67.33%) (p < 0.05). All extracted lipids had triglyceride (TG) as the major component, followed by phospholipid (PL). Oleic acid (C18:1 n-9) constituted as the most abundant fatty acid in all lipids, followed by palmitic acid (C16:0) and linoleic acid (C18:2 n-6), regardless of extraction methods. Docosahexaenoic acid (C22:6 n-3) and eicosapentaenoic acid (C20:5 n-3) accounted for 6.88–7.41 and 1.76–2.51%, respectively. During storage of 30 days at 30°C, lipids extracted by heating under vacuum or by solvent had the higher oxidative stability as indicated by the lower peroxide value (PV), thiobarbituric acid reactive substances (TBARS), conjugated diene (CD) and ρ-anisidine value (AnV). Lower increases in free fatty acid (FFA) content were also found in the samples obtained by those two methods. Extraction of lipid by heating under vacuum or solvent could lower the formation of volatile lipid oxidation products. Thus, extraction method had the profound impact on yield and storage stability of lipids from SVDF.

Practical applications: Asian seabass visceral depot fat is considered as the byproduct during butchering process. This fatty tissue can serve as the potential raw material for lipid production. Several methods have been used for extraction of lipids, in which yield and chemical compositions can be varied. Therefore, the appropriate extraction method should be implemented to increase the efficacy of lipid extraction and to obtain lipid with high quality and oxidative stability. As a consequence, Asian seabass viscera can be better exploited and fish lipid rich in n-3 fatty acids can be produced and used as nutraceutical or supplement.

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