The Presence of Bioactive Compounds in European Eel ( Anguilla anguilla ) Skin: A Comparative Study with Edible Tissue.

The presence of bioactive compounds in European eel ( Anguilla anguilla ) skin was studied. Proximate and lipid class compositions and analysis of the fatty acid (FA) profile (individual FAs; FA groups, i.e., saturated, monounsaturated, and polyunsaturated; FA ratios, i.e., polyunsaturated/saturated, ω3/ω6) were determined and compared to the composition of the eel muscle. As a result, higher ( p < 0.05) levels of proteins (271.6 g·kg -1 ), lipids (38.0 g·kg -1 ), ash (27.7 g·kg -1 ), and ω6 FAs were observed in the skin tissue. Contrary, the muscle tissue showed higher ( p < 0.05) moisture, ω3 FA, and ω3/ω6 ratio values. Regarding lipid classes, a higher ( p < 0.05) proportion of phospholipids (111.1 g·kg -1 lipids), free sterols (104.7 g·kg -1 lipids), α-tocopherol (274.0 mg·kg -1 lipids), and free FAs (43.6 g·kg -1 lipids) was observed in the skin tissue. No differences ( p > 0.05) between both tissues could be detected for triacylglycerol and FA group (saturated, monounsaturated, and polyunsaturated) values and for the polyunsaturated/saturated FA ratio. It is concluded that European eel skin, a by-product resulting from commercial processing, can be considered a valuable source for the food and pharmaceutical industries by providing value-added constituents such as proteins, lipids, ω3 FAs, phospholipids, and α-tocopherol.