Effect of Deployment and Harvest Date on Growth and High-Value Compounds of Farmed Alaria esculenta

Alaria esculenta is a brown seaweed farmed in many European countries for its biomass rich in useful bio compounds. This study aimed to identify the optimal growing season to maximise biomass production and quality. The seeded longlines of the brown seaweed were deployed in the southwest of Ireland in October and November 2019 and samples of the biomass were harvested in different dates, between March and June 2020. Biomass gain and composition, phenolic and flavonoid content (TPC and TFC) and biological activities (antioxidant and anti-hypertensive activities) of seaweed extracts prepared with Alcalase were evaluated. The biomass production was significantly higher for the line deployed in October (>20 kg·m-1). In May and June, an increasing amount of epiphytes was observed on the surface of A. esculenta. The protein content of A. esculenta varied between 11.2 and 11.76% and fat content was relatively low (1.8-2.3%). Regarding the fatty acids profile, A. esculenta was rich in polyunsaturated fatty acids (PUFA), especially in eicosapentaenoic acid (EPA). The samples analysed were very rich in Na, K, Mg, Fe, Mn, Cr and Ni. The content of Cd, Pb Hg was relatively low and below the maximum levels allowed. The highest TPC and TFC were obtained in extracts prepared with A. esculenta collected in March and levels of these compounds decreased with time. In general, the highest radical scavenging activities (ABTS and DPPH), as well as chelating activities (Fe2+ and Cu2+) were observed in early spring. Extracts from A. esculenta collected in March and April presented higher ACE inhibitory activity. The extracts from seaweeds harvested in March exhibited higher biological activity. It was concluded that an earlier deployment allows for maximising growth and harvest of biomass earlier when its quality is at the highest levels. The study also confirms the high content of useful bio compounds that can be extracted from A. esculenta and used in the nutraceutical and pharmaceutical industry.

Bivalve Shellfish Safety in Portugal: Variability of Faecal Levels, Metal Contaminants and Marine Biotoxins during the Last Decade (2011-2020)

Bivalves are a high-value product whose production has markedly increased, reaching 9863 tonnes in Portugal in 2021. Bivalves' habitats-lagoons, estuaries and coastal waters-are exposed to biological and anthropogenic contaminants, which can bioaccumulate in these organisms and pose a significant public health risk. The need to obtain a safe product for human consumption led to the implementation of standardised hygiene regulations for harvesting and marketing bivalve molluscs, resulting in routine monitoring of bivalve production areas for microbial quality, metal contaminants, and marine biotoxins. While excessive levels of biotoxins and metal contamination lead to temporary harvesting bans, high faecal contamination leads to area reclassification and impose post-harvest treatments. In this study, the seasonal and temporal variability of these parameters were analysed using historical data generated by the monitoring programme during the last decade. Moreover, the impact of the monitoring program on bivalve harvesting from 2011 to 2020 was assessed. This program presented a considerable improvement over time, with an increase in the sampling effort and the overall program representativeness. Finally, contamination risk, revising control measures, and defining recommendations for risk mitigation measures are given in the light of ten years' monitoring.

Effects of Industrial Boiling on the Nutritional Profile of Common Octopus (Octopus vulgaris)

Industrial cooking of common octopus (Octopus vulgaris) under well-established procedures is advantageous for current consumers, which demand healthy and convenient food. This work aimed to evaluate the effect of industrial water boiling, without the addition of salt, on the nutritional profile of common octopus. True retentions (TRs) were calculated for essential nutrients and toxic elements. After boiling, the moisture content decreased, resulting in a concentration of other constituents (protein, fat, fatty acids, majority of amino acids, phosphorus, zinc, and iodine). High TRs were obtained for some essential nutrients: 90.2% (eicosapentaenoic acid, EPA), 89.1% (docosahexaenoic acid, DHA), ≥74.6% (indispensable amino acids, IAA), and 86.8% (iodine). In both raw and boiled octopus, polyunsaturated fatty acids (252.2 and 425.1 mg/100 g), leucine (940.1 and 1613.4 mg/100 g), glutamate (1971.5 and 3257.1 mg/100 g), sodium (393.3 and 332.5 mg/100 g), and zinc (12.6 and 16.6 mg/kg) were, respectively, the most abundant fatty acids, IAA, dispensable amino acids, macro, and micro elements. Cadmium, lead, and mercury levels found in boiled octopus were 0.02, 0.10, and 0.08 mg/kg, respectively. The consumption of 150 g (usual portion) of boiled octopus is advisable because it contributes to significant daily intakes of EPA+DHA (>100%), selenium (75.6%), and iodine (12.4%), and 25% of the daily adequate intake of sodium for adults.

Chemical Composition, Nutritional Value, and Safety of Cooked Female Chaceon Maritae from Namibe (Angola)

Despite being highly appreciated and consumed, the nutritional value of Chaceon maritae from Namibe (Angola) had never been studied. In the present work, edible tissues (muscle, ovaries, and hepatopancreas) of boiled female C. maritae caught off Namibe coast in two distinct seasons were analyzed in terms of proximate chemical composition (fat, ash, protein, and moisture), fatty acid and amino acid profiles, cholesterol, essential minerals (macro and trace) and toxic elements. Results showed that, in both seasons, C. maritae muscle was a valuable source of protein, essential amino acids, polyunsaturated fatty acids, and essential elements, especially zinc, selenium, iodine, and copper. Ovaries and hepatopancreas are also good sources of protein, but were richer in fat, particularly when caught in October. Ovarian fat is rich in polyunsaturated fatty acids and that of hepatopancreas has higher values of monounsaturated and saturated fatty acids. Hepatopancreas and ovaries are also good sources of copper and, especially ovaries, of zinc. Moreover, in both seasons, all the edible tissues of C. maritae analyzed presented very low contents of heavy metals (mercury, cadmium, lead, and arsenic).

Environmental contaminants of emerging concern in seafood--European database on contaminant levels

Marine pollution gives rise to concern not only about the environment itself but also about the impact on food safety and consequently on public health. European authorities and consumers have therefore become increasingly worried about the transfer of contaminants from the marine environment to seafood. So-called "contaminants of emerging concern" are chemical substances for which no maximum levels have been laid down in EU legislation, or substances for which maximum levels have been provided but which require revision. Adequate information on their presence in seafood is often lacking and thus potential risks cannot be excluded. Assessment of food safety issues related to these contaminants has thus become urgent and imperative. A database (www.ecsafeseafooddbase.eu), containing available information on the levels of contaminants of emerging concern in seafood and providing the most recent data to scientists and regulatory authorities, was developed. The present paper reviews a selection of contaminants of emerging concern in seafood including toxic elements, endocrine disruptors, brominated flame retardants, pharmaceuticals and personal care products, polycyclic aromatic hydrocarbons and derivatives, microplastics and marine toxins. Current status on the knowledge of human exposure, toxicity and legislation are briefly presented and the outcome from scientific publications reporting on the levels of these compounds in seafood is presented and discussed.

Influence of bioaccessibility of total mercury, methyl-mercury and selenium on the risk/benefit associated to the consumption of raw and cooked blue shark (Prionace glauca)

This study aimed to identify the benefit and risk associated with raw and cooked blue shark consumption taking into account the bioaccessibility of Se, Hg and MeHg, by using in vitro digestion method. Selenium, Hg and MeHg levels were higher in cooked samples, particularly in grilled blue shark. Whereas Se bioaccessibility was above 83% in grilled samples, Hg and MeHg bioaccessibility was lower in grilled samples with values near 50%. In addition, all Se-Health Beneficial Values were negative and the molar MeHg:Se ratios were higher than one. The risk-benefit assessment yielded a maximum consumption of one yearly meal for raw or cooked blue shark, thus emphasizing the need to recommend the consumption of a wider variety of seafood species in a balanced and healthy diet.

Benefits and risks associated with consumption of raw, cooked, and canned tuna (Thunnus spp.) based on the bioaccessibility of selenium and methylmercury

The Se, Hg, and methylmercury (MeHg) levels in raw, cooked (boiled and grilled), and canned tuna (Thunnus spp.) were determined before and after an in vitro digestion, thereby enabling the calculation of the respective bioaccessibility percentages. A risk-benefit evaluation of raw and canned tuna on the basis of the Se and MeHg data was performed. Selenium bioaccessibility was high in tuna, though slightly lower in canned than in raw products. Mercury levels were high in raw and cooked tuna. Hg bioaccessibility percentages were low (39-48%) in the cooked tuna and even lower (<20%) in canned tuna. For the bioaccessible fraction, all molar Se:MeHg ratios were higher than one (between 10 and 74). A probabilistic assessment of MeHg risk vs Se benefit showed that while a weekly meal of canned tuna presents very low risk, raw, boiled, and grilled tuna consumption should not exceed a monthly meal, at least, for pregnant and nursing women.

Effect of sex, maturation stage and cooking methods on the nutritional quality and safety of black scabbard fish (Aphanopus carbo Lowe, 1839)

BACKGROUND

Black scabbard fish (Aphanopus carbo Lowe, 1839) is a deep-water fish resource that is highly appreciated in southern European countries and can accumulate high levels of mercury in the muscle. Currently, European legislation establishes limits for the presence of toxic contaminants in raw seafood, despite these products are generally cooked before consumption. In addition, there is still a lack of information concerning the nutritional quality and contaminants available in cooked products. Therefore, the aim of this study was to assess the effect of sex, maturation stages and three common cooking practices (steaming, grilling and frying) on the toxic elements (Hg, As, Cd and Pb) and nutritional value (chemical, elemental and fatty acid composition) of black scabbard fish.

RESULTS

Few variations occurred between sexes and maturation stages, particularly in fatty acid and elemental content. Concerning cooked black scabbard fish, the greatest differences occurred in fried and grilled samples, attaining higher Hg levels, whereas steamed fish composition was closer to raw black scabbard fish.

CONCLUSION

Raw and cooked black scabbard fish can be considered as a very good source of essential nutrients such as n-3 PUFA, proteins, macro and trace elements. Yet, when the fish is grilled, the Hg content may be above the limits set by EU. Considering the alterations occurred during the cooking processes, steaming seems the best procedure to cook this species.

Nutritional quality and safety of cooked edible crab (Cancer pagurus)

Edible crab (Cancer pagurus) is one of the most important crustaceans consumed in Southern European countries, either as boiled or steamed cooked product. So far, the majority of studies assessing health benefits and risks associated to seafood consumption have been carried out in raw products, despite being generally cooked before consumption, and mostly in muscle tissue. Therefore, the aim of this study was to assess the effect of steaming and boiling on the chemical safety and nutritional value of C. pagurus caught in spring and summer. Generally, chemical and elemental composition of brown meat (tissue in the body cavity comprising mainly gonads and hepatopancreas) differed significantly from muscle (white meat in claws and legs). Additionally, the same tissue revealed differences in chemical and elemental composition of raw and cooked C. pagurus, likely due to water leaching. In contrast, few variations between seasons were observed. The results revealed that the consumption of cooked edible crab muscle should be promoted, whereas brown meat ingestion should be done parsimoniously.