Sutchi catfish (Pangasius hypophthalmus) produced in the freshwater basins of Vietnam, available on the Italian market as frozen or thawed fillets, were studied for their nutritional quality and ...safety aspects. Proximate composition, mineral content, fatty acid profile, unsaponifiable components of the lipid fraction and drip loss during thawing at 5°C were determined on the fillets. Fillets were characterised by high moisture levels (80–85%) and low protein (12.6–15.6%) and lipid (1.1–3.0%) contents. Total lipids were characterised by low cholesterol levels (21–39mg/100g), high percentages of saturated fatty acids (41.1–47.8% of total fatty acid) and low percentages of polyunsaturated fatty acids (12.5–18.8% of total fatty acids), which were mainly represented by linoleic acid (44–59% of total polyunsaturated fatty acids). The mineral composition was characterised by a high sodium content (222–594mg/100g), probably partially due to the sodium tripolyphosphate (E 451) used to retain moisture. As regards safety aspects, the quality of the samples analysed was good, with low residue levels of mercury, organochlorine pesticides and polychlorinated biphenyls.
European perch (
Perca fluviatilis) harvested from three lakes of Central Italy were studied in different seasonal periods of a year to evaluate their nutritional quality and some safety aspects ...related to the pollution of the aquatic environment. The lakes considered, located in the Latium region, differed with respect to their volcanic (Bolsena and Bracciano Lakes) or artificial (Salto Lake) origin. Fillets of fish caught in the three lakes were characterised by good protein (17–19%) and mineral contents and low lipid levels (0.6–1.2%) throughout the year. Total lipids were characterised by low cholesterol levels (41.9–74.7
mg/100
g) and high percentages of total
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3 polyunsaturated fatty acids (27.7–33.8% of total fatty acids), in particular docosahexaenoic acid (14.2–25.3% of total fatty acids). The qualitative analysis of the stomach content of perch confirmed their predatory feeding behaviour. The chemical and nutritional profiles of perch from the three lakes were comparable except for rubidium and cesium levels, which were higher in the muscle tissues of perch from the volcanic lakes. These minerals may represent elements of traceability of the origin of fish. Low levels of organochlorine pesticides and polychlorinated biphenyls, well below the Italian and European action limits, were detected in the muscle tissue of perch from all three lakes.
•The lipid composition of fish is unique among all living species.•Fish consumption has relevant positive effects on human health.•Residues of OC pesticides are detectable in the entire fish food ...chain.•OC pesticides have adverse effects on human health included carcinogenesis.•Fish analyzed is safe as regards OCPs especially when the lipid content is below 2%.
A sampling campaign from 21 sites in Italy was carried out to investigate the presence of organochlorine pesticide residues in different fish species. Samples came from marine fishery and either from sea- or freshwater aquaculture. Fish feed used in some fish farms were also analyzed. Pesticides studied belong to Persistent Organic Pollutants widely used in the past such as DDT, chlordane, heptachlor, and others. To ensure good quality results and proper data validation the main existing guidelines in the field were applied. The instrumental technique was a Dual column–Dual detector Gas Chromatography (GC–ECD and Ion Trap GC–MS) which allowed that complementary data on the same sample were acquired. Results for fishery showed a wide range of concentrations depending from the area and species examined. DDT, the major OC pesticide detected, varied from 0.02 to 130.03ngg−1 edible portion. As regards the products of aquaculture we observed slightly lower average levels of pollutants in a more narrow range of concentration: this is probably due to fish feed used as shown by some measures performed in the present study. Organochlorine pesticide residues were detected in all samples examined but they were generally well below the existing tolerance or action levels. Also the estimated daily intakes are well below than those recommended by WHO. This is a good indication about OCPs in the areas investigated but some further considerations on fish safety must be taken into account. An example on how fishes may act as bioindicators is reported.
•The MS ortho effect was used for the first time in the analysis of PCBs in fish.•Other new observations on mass spectra have solved old problems often reported.•An accurate gas chromatographic setup ...was combined with these findings.•The seven indicators were analyzed via GC–MS in a simple but innovative way.
A simple instrumental procedure was developed to carry out the not simple analysis of PCBs in fish samples. PCBs with the same degree of chlorination (the isomers) are expected to be totally indistinguishable among them by all existing detectors and by all existing mass spectrometers, and there is no apparent solution in those frequent cases where two isomers chromatographically coelute. Generally such coelutions are solved by means of multidimensional GC, but it is a complex technique impractical for most laboratories. The present research focuses on the seven important “indicator PCBs” by using the mass spectrometer in an innovative way. The “mass spectrometric ortho effect” was usefully exploited in addressing coelutions between isomers. Other new important observations on mass spectra were decisive in solving the apparent problem arising from coelutions between higher chlorinated PCBs with the lower chlorinated ones when low-resolution MS is used. With the proposed procedure, the seven indicators are analyzed in a simple way and with a degree of accuracy never observed with the conventional gas chromatography. The method was applied to some Bluefin Tuna fish samples of big size suspected to have not negligible levels of PCBs due to the high position of this species in the food chain. The supposition was partly confirmed. On the basis of the results here obtained, the recently introduced EU Regulation on six of the seven indicators shows one critical point: in the present paper, an amendment to the Regulation is proposed. A number of important validation measures are reported.
This study investigated mercury contamination levels in eight commercially valuable crustacean species caught off the Central Adriatic and Tyrrhenian coasts of Italy. Total mercury levels were ...measured by Thermal Decomposition-Amalgamation-Atomic Absorption Spectrophotometry. Results showed a high variability among species with values ranging from 0.070 to 1.24 (mg kg
−1
wet weight). The lowest mercury levels were detected in caramote prawn (Penaeus kerathurus), warty crab (Eriphia verrucosa) and European spider crab (Maja squinado), decapods living in shallow waters. Levels exceeding the limits established by the European Commission were found in species living in close contact with bottom sediments: deepwater rose shrimp (Parapenaeus longirostris), blue and red shrimp (Aristeus antennatus) and Norway lobster (Nephrops norvegicus). For shrimps, the inter-individual variability observed was mostly related to the body size, indicating the accumulation of mercury with age. An estimation of the human intake of mercury associated to the consumption of the crustaceans sampled and its comparison with the Tolerable Weekly Intake are provided.
•The lipid content and profile of red mullet in spring and in autumn differed.•Total lipid levels were low in spring, the reproductive season, and high in autumn.•Red mullet from the two sites proved ...to be a good source of n-3 PUFA.•Cholesterol levels were low in red mullets from both sites and seasons.
Proximate composition, unsaponifiable lipid components (cholesterol, squalene, tocopherols, all-trans retinol, total carotenoids) and fatty acid profile were evaluated on red mullet (Mullus barbatus) caught in the Central Tyrrhenian and Central Adriatic seas (Italy). The study was conducted in spring, the reproduction period, and in autumn, the period of maximum recruitment and market demand for this species. Results showed that, in fish from both sites, protein (18.1–18.8g100g−1), nonprotein nitrogen (0.32–0.35g100g−1), ash (1.27–1.42g100g−1) and cholesterol (56.8–73.7mg100g−1) contents were almost stable. Total lipid levels were highly variable, with very low levels in spring (0.96–1.48g100g−1) and high levels in autumn (7.28–8.72g100g−1). On a total fatty acids basis, polyunsaturated fatty acids (PUFA) were significantly higher in spring (30–40% of total fatty acids), when fish was lean, than in autumn (20%), while monounsaturated fatty acids were significantly higher in autumn (35–38%) than in spring (18–29%). Saturated fatty acids were almost stable throughout the year (34–39% of total fatty acids). Red mullet from the two sites showed a good nutritional value; in particular they proved to be a good source of n-3 PUFA, which accounted for 75–80% of total PUFA, regardless of the fishing season. However, it was in autumn that red mullet exhibited the highest content of n-3 PUFA (>1000mg100g−1 wet fillet). The comparison of samples by geographical origin showed no difference in autumn, while slight differences were observed in spring.
Total mercury levels were measured in 42 commercial fish species caught off the Central Adriatic and Tyrrhenian coasts of Italy and in 6 aquaculture species. The study on wild fish covered species ...differing in living habitat and trophic level. The study on farmed fish covered marine and freshwater species from intensive and extensive aquaculture and their feed. Mercury levels were analysed by thermal decomposition-amalgamation-atomic absorption spectrophotometry. Total mercury concentrations in the muscle of wild fish showed a high variability among species (0.025-2.20 mg kg
−1
wet weight). The lowest levels were detected in low trophic-level demersal and pelagic-neritic fish and in young individuals of high trophic-level species. Levels exceeding the European Commission limits were found in large-size specimens of high trophic-level pelagic and demersal species. Fish from intensive farming showed low levels of total mercury (0.008-0.251 mg kg
−1
). Fish from extensive rearing showed variable contamination levels, depending on the area of provenience. An estimation of the human intake of mercury associated to the consumption of the studied fish and its comparison with the tolerable weekly intake is provided.
This study was aimed at evaluating the nutritional properties of bogue (
Boops boops) and horse mackerel (
Trachurus trachurus), fish species present throughout the Mediterranean and highly ...represented in the catch of the Italian trawl fishery. In Italy such fish species are scarcely known by consumers and are not sought-after on the market, especially when the fish are small. Proximates, unsaponifiables and fatty acid profile of bogue and horse mackerel caught by trawlers in different seasons of the year along the southern Adriatic coast of Italy were evaluated. Results showed that both species were characterised by good protein contents (18–20
g/100
g) and low lipid (1–2
g/100
g) and cholesterol (50–70
mg/100
g) levels at any season considered. Along with α-tocopherol (0.45–0.70
mg/100
g), δ-tocopherol was found at a lower level (0.04–0.09
mg/100
g) while no detectable amounts of the γ-isomer were observed in either species. The fatty acid profiles of horse mackerel and bogue exhibited a seasonal fluctuation. They were characterised by high proportions of polyunsaturated fatty acids (PUFA), ranging from about 30% of total fatty acids in summer to more than 40% of total fatty acids in spring and winter, and by high n-3/n-6 PUFA ratio values (4.4–6.8 for bogue, 7.4–8.2 for horse mackerel). On a quantitative basis, in bogue total n-3 PUFA amounted to 0.29–0.43
g out of 0.33–0.54
g of total PUFA per 100
g wet fillet. In horse mackerel total n-3 PUFA ranged between 0.37
g and 0.43
g/100
g and total PUFA between 0.41 and 0.49
g/100
g wet fillet. The atherogenic (0.46–0.63) and thrombogenic (0.22–0.38) indexes calculated on bogue and horse mackerel were comparable to those of fish species of higher commercial value. The nutritional properties of these underutilised species may be considered comparable to those of other low-fat fish species from the wild and also from aquaculture present on the Italian market and meeting consumers’ preferences.
In this study the effects of soybean and linseed oils on chemical and sensory characteristics of fillets were evaluated in the freshwater fish tench (
Tinca tinca L.). Five experimental diets, ...differing only in the relative amount of soybean and linseed oil, were formulated and the experiment was conducted on 360 sub-adult tench for 12 weeks. The fatty acid composition of muscle reflected that of the diets and significant correlations were observed. Diets containing higher amounts of
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6 fatty acids were responsible for an increased level of
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6 fatty acids in the fish flesh. Consequently, an increase in the relative amount of
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6-derived volatile aldehydes was also observed. These latter compounds are generally reported to contribute negatively to the general aroma of fish muscle and, consistently, the results of the sensory analysis showed a high value for the “off-flavour” attribute for fish fed the diet containing only
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6-rich soybean oil.
