From Raw to Cooked: Proximate Composition, Fatty Acids and Fat-Soluble Vitamins in Bluefish (Pomatomus saltatrix) from the Black Sea

Bluefish (<i>Pomatomus saltatrix</i>) is an important Black Sea species; however, quantitative data on how traditional household cooking affects its nutritional composition remain limited. This study assessed the effects of grilling, pan-frying, and smoking on the proximate composition, fatty acid profile, fat-soluble vitamins, antioxidant pigments, and cholesterol content of bluefish. Cooking led to moisture reductions of 7-18%, accompanied by increased total lipid content (26-80%). Crude protein content decreased in grilled and smoked fish and increased in pan-fried samples. Pan-frying resulted in the largest reduction in long-chain n-3 PUFA, with reductions of approximately 25.2% for EPA and 20.3% for DHA (in mg/100 g wet weight), probably due to higher temperature and absorption of other fatty acids from the cooking oil. Combined EPA + DHA levels ranged from 743 to 2223 mg/100 g (wet weight), with smoked fish showing the highest values. Vitamin E exhibited substantial losses during grilling but was largely preserved during smoking, whereas astaxanthin was undetectable in the grilled samples. Vitamin D₃ demonstrated moderate thermal stability. Overall, each cooking method induced distinct quantitative changes driven by moisture loss and changes in the relative proportions of individual fatty acids within the total lipids. Grilling and smoking were the most favorable for retaining long-chain n-3 PUFA and key micronutrients.