Chemical quality and sensory profile of the Mediterranean farmed fish shi drum (Umbrina cirrosa) as affected by its dietary protein/fat levels

Two groups of identically-reared shi drum, having received different diets (Group A: 45% protein and 16% fat and Group B: 48% protein and 12% fat), were compared for their yields and their chemical and sensory quality. They exhibited similar dressing and filleting yields, fat deposit and fillet composition. Differences were observed in the fillet fatty acids, with group B exhibiting higher 16:1ω-7, 16:1ω-9, 16:0, 18:0, and total saturate contents. Their fillet volatile compounds also differed (group A, in particular, contained higher levels of carbonyl-compounds). A triangle test revealed that the two shi drum groups were perceived as sensory different. A Check-All-That-Apply (CATA) test showed that group A (high dietary lipids) was perceived as having a significantly higher 'fish oil' aroma, hardness and elasticity, while group B was characterised mainly by higher 'sweet taste', higher 'hay' and 'fresh seaweed' aroma and 'crab/prawn' flavour.