Urchins’ gonads are a highly prized delicacy in some countries and harvesting of these echinoderms has also been found beneficial in areas of great proliferation to allow restoration of kelp forests. Gonads quality depends on food availability and spawning cycle and the most important quality parameters are color, texture, and taste. Seasonal and geographical variations were investigated through the analysis of the biometrics, proximate composition, color, and pigments content of the Edible sea urchin Echinus esculentus gonads. Urchins were harvested from two different locations from Mid-Norway fjords in four seasons. These two locations are assumed to have different anthropogenic pressure. Therefore, marine pollution was also analyzed by determining the concentration of heavy metals and perfluorinated substances.
This study aimed to determine the best season and location for harvesting high quality gonads in terms of nutritional value (proteins, lipids, and fatty acids content), aspect (color and pigments content), and microbial composition. Moreover, the safety of gonads as food was also determined.
A negative correlation was found between gonad index and total body weight between seasons and locations. A statistically significant difference was noticed in the lipids content. However, no difference was reported for the other parameters of the proximate composition. In terms of fatty acid profile, a high concentration of PUFAs (33.3%-39.4%) mainly EPA ad DHA was determined followed by SFAs (22%-29.3%) especially palmitic acid (C16:0), and MUFAs (16%-17.3%).
The harvesting season had a greater impact on the microbial diversity than the geographical location. The microbial communities were mainly dominated by bacteria taxa belonging to Shewanellaceae, Vibrionaceae and Yersianiceae families in all seasons and locations.