Sea urchin population harvest in the North Atlantic coast of Portugal was characterized in terms of gonad yield, nutritional composition and important market-related traits, over one reproductive cycle (March 2016 to March 2017). Most of the quality attributes showed a seasonal variation strongly dependent on sea urchin sex. Maximum gonad yield (18%) was observed in March 2017. A single spawning event occurred between May and July. Gonads are rich sources of protein (12–18% WW) with low fat content (≤6% WW), that increase during the gametogenic stages of recovery and growing (November-December). Polyunsaturated fatty acids were the dominant class in both sexes (4.2–14.7 mg.g⁻¹ WW), being preferentially accumulated in females. Total gonads carotenoid varied seasonally, with the highest level being observed in males during spawning season. Echinenone was the main pigment present in gonads, showing highest concentrations in males during spawning and gonad recovering. During the growing and early maturation period gonads were more reddish, yellowish and brighter, as well as more firm, irrespectively of the sex. Based on all seasonal changes affecting gonad yield and quality, the period between November and February seems the most suitable to harvest high quality gonads in the Atlantic coast of Portugal.

Synthetic vitamin E is commonly used in aquafeeds to prevent oxidative stress in fish and delay feed and flesh oxidation during storage, but consumers’ preferences tend towards natural antioxidant sources. The potential of vegetable antioxidants-rich coproducts, dried tomato (TO), carrot (CA) and coriander (CO) was compared to that of synthetic vitamin E included in diets at either a regular (CTRL; 100 mg kg⁻¹) or reinforced dose (VITE; 500 mg kg⁻¹). Natural antioxidants were added at 2% to the CTRL. Mixes were then extruded and dried, generating five experimental diets that were fed to European sea bass juveniles (114 g) over 12 weeks. Vitamin E and carotenoid content of extruded diets showed signs of degradation. The experimental diets had very limited effects on fish growth or body composition, immunomodulatory response, muscle and liver antioxidant potential, organoleptic properties or consumer acceptance. Altogether, experimental findings suggest that neither a heightened inclusion dose of 500 mg kg⁻¹ of vitamin E, nor a 2% inclusion of natural antioxidants provided additional antioxidant protection, compared to fish fed diets including the regular dose of 100 mg kg⁻¹ of vitamin E.

Paracentrotus lividus gonads are receiving increasing interest for their unique sensory attributes. However, the sensory profile of this highly demanded gourmet product has not yet been well described, and doing so may potentially benefit the gonads' marketability and acceptability. The main goal of this study was to build a sensory profile of sea urchin (Paracentrotus lividus) gonads, to evaluate differences between sex and harvest location. Eighty untrained panellists (regular consumers of seafood) were asked to evaluate four samples of raw sea urchin gonads (inside a sea urchin test), divided by sex and harvest location. The panellists evaluated overall liking and acceptance (Food Action Scale), followed by a Rate-All-That-Apply (RATA) ballot with a list of 22 sensory attributes divided into four dimensions: appearance (6), odour (6), texture (4) and taste (6). No significant effects of sex and harvest location were identified for liking, but a significant effect of the sex for the Food Action Rating Scale (FACT) was identified. Sensory profiling clearly separated gonads according to sex, with females being more appealing than males. Females were strongly correlated with a pleasant and intense tropical taste, as well as an overall appealing and grainy appearance and a pleasant tropical odour, while males had a slimy appearance and a milky white exudate. When compared with the Check-All-That-Apply (CATA) approach used in our previous study, the use of the RATA approach allowed to discriminate female gonads according to their origin, with those from Praia Norte being firmer, more resilient and more appealing than the ones from Carreço. This study reinforced the fact that female sea urchins tend to present an intense and pleasant tropical taste and a pleasant tropical odour, thus being more appealing to the panellists, contributing valuable information for future nutritional aquaculture studies aiming to enhance sea urchin gonads' attributes and, subsequently, their market valorisation.