The biochemical composition of fin whale blubber

Fin whale blubber is a heterogenous tissue containing 8.9–77.4% lipid, 3.1–33.8% protein, and 0.07–0.73% ash by wet weight. The blubber may be subdivided into three macroscopically distinct zones. The outermost zones contain up to twice the lipid content of the innermost zone adjacent to the muscle, which contains more protein. Anterior ventral blubber contains less lipid, more protein (of which 50% is collagen), and more ash than posterior dorsal blubber. Foetal blubber contains 1.2% lipid, 10.6% protein, and 0.93% ash by wet weight. Blubber lipid contains ca. 60% triacylglycerol and ca. 25–30% free fatty acid, compared with ca. 25% triacylglycerol and ca. 10% free fatty acid in foetal blubber lipid, which also contains ca. 40% phospholipid. The high free fatty acid component is certainly partly due to postmortem hydrolysis in samples analysed. Monounsaturated fatty acids comprise ca. 60% of blubber lipid; 16:0, 16:1, 18:1, 20:1, 22:1, and 22:6 predominate, similar to the dietary intake. The predominant fatty acids in the outermost and the innermost blubber zones are 22:1 and 16:0, respectively. This may have significance in energy storage and catabolic breakdown.