Kriton Grigorakis

Organoleptic and chemical quality of farmed meagre (Argyrosomus regius) as affected by size

Two fish groups differing in size (average weighing 830±220 and 1600±350 g, respectively) were evaluated for their sensory, somatometric and chemical quality characteristics. No differences were found in the yields and fillet proximate composition of the two groups. Although taste panels indicated high acceptability for both groups, the large fish received significantly better hedonic rates for their overall acceptance. Differences were also observed in the fatty acid profiles of the two groups with the large fish having significantly higher 18:2n-6 and total n-6 contents. Their volatile compounds also differed, with small fish containing higher total amount, as well as more total aldehydes, furans and pyrazines. All these findings indicate size-dependent quality alterations, but also sufficient quality for small fish to be commercialised.

Sensory characterization, physico-chemical properties and somatic yields of five emerging fish species

Aquaculture plays an important role in supplying the fresh fish. However its production is dominated by only few long-established species that in turn limit the variety of available products in the market. Therefore, new fish species need to be properly introduced to create a diversification in the current market. In order to achieve this goal, it is important to know, understand and characterize their quality features so they can be addressed to local and global markets. Sensory, compositional, instrumental texture parameters and somatic properties of five emerging fish species, namely wreckfish, greater amberjack, grey mullet, meagre, and pikeperch, were examined for characterization purposes. Sensory references were specifically developed for the training of the assessors, both from a qualitative and quantitative perspective. Twenty two sensory descriptors were used for describing the samples. Several differences were observed among the measured parameters. Somatic measures revealed the filleting yield to be the most important of them. Regarding the compositional parameters, fat content was among the most relevant discriminating aspect between species, while hardness was among the most differentiating ones when dealing with texture. Greater amberjack was described with sour flavor, pikeperch was associated to an earthy flavor and grey mullet was characterized by bitter flavor. Sensory firmness was clearly distinctive for wreckfish, while meagre related to juicy texture. The analysis of the relationship between all parameters provided important correlations, especially those related to texture parameters, fat content, laminar structure and teeth adherence. The species in this study exhibited a wide range of physicochemical and sensory characteristics that show their potential for being further exploited when designing new products.

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

Abstract 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.