Fatty Acid Composition and Oxidative Stability of the Lipid Fraction of Skin-On and Skinless Fillets of Prussian Carp (Carassius gibelio)

SIMPLE SUMMARY: Examination of the proximate nutritional composition of Prussian Carp fish fillets revealed substances with health-promoting or functional properties for humans. High-value constituents, such as eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids, were higher in skin-on fillets than in skinned products, but nutritionally controversial compounds were higher in the former. Fortunately, the obtained values did not exceed the limits adopted for fresh fish and/or fish fit for consumption. This study implies that Prussian Carp can be used on a larger scale in the food industry, thereby facilitating control of the growing domestic population of this species. ABSTRACT: The aim of the study was to compare the fatty acid profile and content and the oxidative stability of the lipid fraction of Prussian Carp (Carassius gibelio) fillets with and without skin. Carp specimens were obtained in spring from a fish farm located in the Lublin Voivodeship. The research material consisted of skin-on (n = 12) and skinless (n = 12) fillets (hand-filleted). Their chemical composition (water, ash, protein, and fat content), calorific value, and nutritional quality index (NQI) were analysed, as well as their fatty acid content and profile. The oxidative stability of the lipids was assessed on the basis of the peroxide value (PV), thiobarbituric acid reactive substances (TBARS) value, and the content of the conjugated dienes and trienes (CD and CT), while determination of the degree of fat hydrolysis was based on the acid value (AV) and free fatty acids (FFA). The Carp fillet with skin contained significantly (p ≤ 0.01) more fat (by 2.69 pp) and calories (by 92.16 kJ∙100 g(−1)) than the skinless fillet, and over three times as much n-3 polyunsaturated fatty acids (n-3 PUFA), including eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids. In the skin-on fillet, the lipid oxidation and hydrolysis parameters were significantly higher, but did not deviate from the values specified for fresh fish and/or fish fit for consumption.