Carlos Cardoso

Quality Changes During Storage of Fish Sausages Containing Dietary Fiber

ABSTRACT Two groups of fish sausages were studied regarding quality changes during an 80-day storage experiment at 2°C. Formulations were identical with the exception of pork fat, 7.8%(w/w) in the control group, replaced by 5.2% (w/w) chicory root inulin and 2.6% (w/w) extra hake mince in the other. Control sausages were more elastic, cohesive, springy, and succulent, while substituted sausages presented higher gel strength and hardness. Both sausages presented an acceptable quality not only immediately after their production but also during storage at 2 ± 1°C. However, gel strength as well as textural and sensory hardness increased, and succulence showed a clear reduction during storage time. Moreover, for substituted sausages, saltiness and astringent aftertaste increased. Formulation had no effect on the microbial growth, which was low. However, microbiological changes occurred during storage time: growth of anaerobic spore-formers since the 45th and 43rd day for control and substituted sausages, respectively.

Evaluation of the risk/benefit associated to the consumption of raw and cooked farmed meagre based on the bioaccessibility of selenium, eicosapentaenoic acid and docosahexaenoic acid, total mercury, and methylmercury determined by an in vitro digestion model.

The bioaccessibility of total lipids, EPA, DHA, Se, Hg, and MeHg in raw and cooked meagre (Argyrosomus regius) was studied by using an in vitro digestion method. A risk-benefit assessment of raw and cooked meagre on the basis of the bioaccessibility data was carried out. The bioaccessibility of total lipids was generally high in raw and cooked meagre with exception of grilled fish. For EPA and DHA, bioaccessibility percentages were low never surpassing the 50% in raw, boiled, and grilled meagre. The bioaccessibility percentage of Se was equal or higher than 82% (grilling treatment). Likewise, for Hg and MeHg, high bioaccessibility values were determined with exception of grilled meagre, displaying lower values of 54% and 64%, respectively. The risk-benefit probabilistic assessment brought about a recommendation of a maximum consumption of two weekly meals for boiled or roasted meagre and three weekly meals for grilled meagre.

Survey into the seafood consumption preferences and patterns in the portuguese population. Gender and regional variability

With the purpose of achieving a deeper knowledge of one of the most important seafood markets in Europe, a survey into the seafood consumption preferences and patterns in the Portuguese population was carried out. A thorough, comprehensive, and simple questionnaire was developed. Consumers were asked to state their preferences towards fish products, their consumption frequencies, the average meal portion, and the usual culinary treatments. Respondents provided personal data: gender, age, geographical location, education level, weight, height, and health condition. This paper presents the first part of the studys results, focusing mainly on the gender and regional variables. Portuguese consumers prefer wild to cultured fish as well as fat to lean fish. Chilled fish is preferred over frozen, salted/dried, canned, and smoked fish, being the latter the least preferred. Soaked cod, hake, and canned tuna are the most eaten seafood products. Men prefer to a greater extent wild and smoked fish. Men consume more cephalopods and sardine and women eat more frequently hake, pink cusk-eel, and redfish. Coastal populations prefer wild fish. Algarve (southern Portugal) consumers exhibit a stronger tendency to wild and whole fish and consume more sardine and sole. Madeira archipelago consumers are particularly fond of black scabbard fish.

Improvement of Cold and Thermally Induced Gelation of Giant Squid (Dosidicus gigas) Surimi

Depending on the season of capture, giant squid (Dosidicus gigas) surimi processed by isoelectric precipitation presents low gel strength. Addition of microbial transglutaminase (MTGase) and application of high isostatic pressure (300 MPa) to improve physicochemical properties were assayed for purposes of making “suwari” gels and heated gels for use in restructured products which have a raw or cooked appearance. The physicochemical properties of both pressurized and unpressurized gels induced by application of 30°C/1 h improved when MTGase was added. In contrast, addition of MTGase was less effective in gels subsequently heated at 90°C/30 min after 30°C/1 h. High pressure treatment for 30 min at 300 MPa and 15°C helped to produce gels with better mechanical and water binding properties, whether treated for 30°C/1 h only or for 30°C/1 h plus 30-min heat treatment at 90°C. High pressure treatment also reduced lightness.

Methylmercury risks and EPA+DHA benefits associated with seafood consumption in Europe.

The intake of methyl-Hg and EPA + DHA through consumption of seafood in Europe as well as the associated probability of exceeding the provisional tolerable weekly intake (PTWI) and the recommended daily intake (RDI), respectively, were estimated by combining methyl-Hg and EPA + DHA contents in the five most consumed seafood species with hypothesized consumption distributions for eight European countries, chosen on the basis of size and representative significance. Two estimators were used: plug-in (PI) and tail estimation (TE). The latter was based on the application of the extreme value theory to the intakes distribution curves. Whereas contents data were collected from own database and published scientific papers, consumption data were obtained from statistical sources of the various countries. Seafood consumption levels varied considerably between countries, from 140 in the United Kingdom to 628.5 g/(person.week) in Iceland. The main consumed species were also different between countries. The probability of exceeding the methyl-Hg PTWI ranged from 0.04% in the United Kingdom to 9.61% in Iceland. Concerning the probability of exceeding the RDI of EPA + DHA, Iceland was third, after Portugal (66.05%) and Spain (61.05%) and the United Kingdom was the last (0.32%). While TE was most accurate for small probabilities, PI yielded best estimates for larger probabilities.

The emerging farmed fish species meagre (Argyrosomus regius): How culinary treatment affects nutrients and contaminants concentration and associated benefit-risk balance

The effect of cooking methods (boiling, grilling, and roasting) on the proximate and mineral composition, contaminants concentration and fatty acids profile was evaluated aiming to understand the benefits and risks associated to the consumption of the emerging farmed fish meagre (Argyrosomus regius). All the treatments led to lower moisture content. After grilling and roasting, the SFA, MUFA and PUFA contents increased. There was no degradation of EPA and DHA during the culinary processes. Significant retention of minerals in grilled and roasted meagre samples was registered. For Pb and Cd there were no concentration differences between culinary treatments and regarding raw fish. Whereas As level was higher in grilled meagre, total Hg and Me-Hg values were augmented in grilled and roasted meagre. The consumption of meagre is advisable due to the low and healthy fat, high selenium and protein content. Grilling would be the best culinary treatment due to the retention of protein, EPA, DHA and minerals. But as the risk of ingestion of Me-Hg content also increases, based on the risk assessment, intake should not exceed two weekly meals, provided that no other important Me-Hg food source is present in the diet. Otherwise, even this maximum threshold should be lower.

From fish chemical characterisation to the benefit-risk assessment--part A.

Proximate composition, fatty acid profile, cholesterol, α-tocoferol content and essential (K, Na, Cl, S, Mg, Ca, Zn, Cu, Fe, Mn, and Se) and contaminant element (Hg/MeHg, Cd, Pb, and As) levels in silver scabbardfish (Lepidopus caudatus), hake (Merluccius merluccius), and ray (Raja spp.) were investigated. Results showed that these species contain high protein, low cholesterol and energy levels, being its consumption recommended. Polyunsaturated fatty acids (PUFA) were the dominant group of the fatty acids, being 80% of the n-3 family. Attending to the dietary reference intakes (DRIs), these fish species are a good source of Se and the other minerals can give a relevant contribution to the DRIs in a balanced diet. More than one weekly meal of silver scabbardfish has to be avoided due to the organic mercury concentration. More accurate dietary recommendations require a probabilistic assessment, which will be the focus of this studys Part B.

Estimation of Risk Assessment of Some Heavy Metals Intake Through Black Scabbardfish (Aphanopus carbo) Consumption in Portugal

The intake of Cd, methyl-Hg, and Pb through consumption of black scabbardfish (BSF) (Aphanopus carbo) in Portugal as well as the associated probability of exceeding the respective provisional tolerable weekly intakes (PTWIs) was estimated. For this purpose, the contamination levels of heavy metals in this fish species were combined with constructed consumption scenarios or with a hypothesized consumption distribution. Whereas Cd and Pb posed no serious risk, the consumption of at least one portion of BSF per month as well as the hypothetical study in the Portuguese population produced nonnegligible probabilities of surpassing the PTWI for Me-Hg. Risk assessment for Portuguese consumers revealed a higher risk regarding Me-Hg, 1.19% and 1.81% with the plug-in (PI) and the tail estimation (TE) estimators, respectively. On the other hand, the risk for Cd and Pb was less than 1 in 100,000. TE was more realistic and accurate for Cd and Pb. Concerning Me-Hg, TE and PI estimators produced similar results. Furthermore, the limitations of a deterministic approach were shown.

Dietary DHA and health: cognitive function ageing

DHA is a key nutritional n-3 PUFA and needs to be supplied by the human diet. DHA is found in significant amounts in the retinal and neuronal cell membranes due to its high fluidity. Indeed, DHA is selectively concentrated in the synaptic and retinal membranes. DHA is deemed to display anti-inflammatory properties and to reduce the risk of CVD. Consumption of larger amounts of DHA appears to reduce the risk of depression, bipolar disorder, schizophrenia and mood disorders. Conversely, it has been shown that loss of DHA from the nerve cell membrane leads to dysfunction of the central nervous system in the form of anxiety, irritability, susceptibility to stress, dyslexia, impaired memory and cognitive functions, and extended reaction times. DHA plays an important role in ensuring a healthy ageing, by thwarting macular degeneration, Alzheimers disease, and other brain disorders at the same time as enhancing memory and strengthening neuroprotection in general. A reduced level of DHA is associated with cognitive decline during ageing. Different mechanisms for this fundamental DHA role have been put forward. Namely, neuroprotectin D1, a DHA derivative, may support brain cell survival and repair through neurotrophic, anti-apoptotic, and anti-inflammatory signalling. Many of the effects of DHA on the neurological system may be related to signalling connections, thus leading to the study of the related signalolipidomics. Therefore, the present review will focus on the influence of DHA deficiency upon ageing, with specific emphasis upon neurological disorders related to cognitive function and mental health.

Tocopherols in Seafood and Aquaculture Products.

Fish products contain various nutritionally beneficial components, namely, ω3-polyunsaturated fatty acids (ω3-PUFA), minerals, and vitamins. Particularly, tocopherols (α-, β-, γ-, and δ-tocopherol) can be provided by seafood and aquaculture products. Hence, this review shows the various aspects of tocopherols in seafood and aquaculture products. For tocopherol determination in these products, HPLC methods coupled with diode array detection in the UV area of the spectrum or fluorescence detection have been shown as sensitive and accurate. These newest methods have helped in understanding tocopherols fate upon ingestion by seafood organisms. Tocopherols pass through the intestinal mucosa mainly by the same passive diffusion mechanism as fats. After absorption, the transport mechanism is thought to consist of two loops. The first loop is dietary, including chylomicrons and fatty acids bound to carrier protein, transporting lipids mainly to the liver. The other is the transport from the liver to tissues and storage sites. Moreover, tocopherol levels in fish organisms correlate with diet levels, being adjusted in fish body depending on diet concentration. For farmed fish species, insufficient levels of tocopherols in the diet can lead to poor growth performance or to nutritional disease. The tocopherol quantity needed as a feed supplement depends on various factors, such as the vitamer mixture, the lipid level and source, the method of diet preparation, and the feed storage conditions. Other ingredients in diet may be of great importance, it has been proposed that α-tocopherol may behave as a prooxidant synergist at higher concentrations when prooxidants such as transition metals are present. However, the antioxidant action of tocopherols outweighs this prooxidant effect, provided that adequate conditions are used. In fact, muscle-based foods containing higher levels of tocopherol show, for instance, higher lipid stability. Besides, tocopherols are important not only from the nutritional point of view but also from the physiological one, since they are involved in many metabolic processes in the human organism. Moreover, synergistic interactions with selenium and ascorbic acid have been reported. It deserves attention that there is evidence tocopherols taken with food can prevent heart disease, while no such evidence was found for α-tocopherol as supplement. From this perspective, eating fish is advisable, since, for instance, a 100 g serving of salmon may provide nearly 14% of recommended dietary allowance.