Trace element content of fish feed and bluegill sunfish (Lepomis macrochirus) from aquaculture and wild source in Missouri

Trace element content of fish feed and bluegill sunfish muscles (Lepomis macrochirus) from aquaculture and natural pond in Missouri were determined using the inductively coupled-plasma optical emission spectrometer (ICP-OES) and the direct mercury analyzer (DMA). Dietary intake rates of trace elements were estimated. Dogfish muscle (DORM-2) and lobster hepatopancreas (TORT-2) reference standards were used in trace element recovery and method validations. The average elemental concentrations (mg/kg diet, dry wt.) of fish feed were: As 1.81, Cd 2.37, Co 0.10, Cr 1.42, Cu 8.0, Fe 404, Mn 35.9, Ni 0.51, Pb 9.16, Se 1.71, Sn 20.7, V 0.09, Zn 118 and Hg 0.07. The mean elemental concentrations (μg/kg wet wt.) in bluegill muscles from both aquaculture and wild (in parenthesis) sources were: As 0.36 (0.06), Cd 0.28 (0.01), Co 0.0 (0.0), Cr 0.52 (0.05), Cu 0.38 (0.18), Fe 17.5 (2.43), Mn 0.18 (0.24), Ni 0.18 (0.04), Pb 1.03 (0.04), Se 0.34 (0.30), Sn 0.66 (0.42), V 0.02 (0.01), Zn 6.97 (9.13) and Hg 0.06 (0.24). Kruskal–Wallis chi square indicated significant differences in As, Cd, Co, Cr, Cu, Fe, Ni, Pb, Sn, V, Zn and Hg (P < 0.001), Se (P < 0.01) and Mn (P < 0.05) across the sampling locations. Dietary intake rates, estimated from weekly consumption of 228 g of aquaculture and wild bluegills, posed no health risks for approximately 85% of all samples.     

Metal concentration of wild edible mushrooms in Soguksu National Park in Turkey

Twelve varieties of fruiting bodies of wild edible mushrooms collected in 2002 from Soguksu National Park, Ankara, Turkey were analysed for Pb, Cd, Zn, Fe, Mn, Cu, Cr, Ni, and Co contents by inductively coupled plasma optical emission spectrometry (ICP-OES). Dried samples were dissolved by microwave digestion. The contents of trace metals in the mushroom samples were found in the ranges: 0.7–4.2, 0.31–54.2, 29–146, 138–1714, 10–77, 6–187, not detected–21.6, 0.7–4.2 and not detected–5.2 mg kg⁻¹ for Pb, Cd, Zn, Fe, Mn, Cu, Cr, Ni and Co, respectively. The levels of Pb and Cd analysed in all edible mushroom samples except Agaricus arvensis and Ramaria obtusissima for Cd were found to be lower than the legal limits.     

Effects of different cooking methods on the mineral contents of wild and farmed sea bream (Sparus aurata)

The effects of different cooking methods (steaming, boiling, oven cooking, grilling, frying in olive oil, frying in soybean oil, frying in corn oil and frying in sunflower oil) on mineral contents (Ca, Mg, K, Na, Fe, Zn, Cu and Mn) of wild and farmed sea bream (Sparus aurata) were determined. The moisture rate decreased significantly (P < 0.05) after boiling, grilling, oven cooking and frying but remains stable after steaming. The fat content increased with different frying treatments. The Ca, Mg, Na, K and Zn contents of wild and farmed sea bream cooked by almost all methods significantly decreased (P < 0.05). The Cu content in grilled wild and farmed sea bream increased significantly (P < 0.05). Losses of mineral content in fried sea bream were higher than those of fish cooked by other methods. On comparing the raw and cooked fish, the results indicated that cooking had considerable effect on the mineral contents.     

CHANGES IN QUALITY DURING STORAGE OF VACUUM-PACKED SEA BASS (DICENTRARCHUS LABRAX, Linnaeus, 1758) COOKED BY DIFFERENT METHODS

This work evaluates the chemical, microbiological and sensorial characteristics of vacuum-packed sea bass processed by different cooking methods under different time/temperature conditions and storage at 2C. The heat treatments applied in core were: 5 min, at 180C for frying, 30 mi, at 230C for baking, and 16 min at 2450 MHz for microwave cooking. Chemical, microbiological and sensory quality changes were investigated periodically. In all groups; the total viable and psycrophilic bacteria counts increased throughout the storage period of vacuum-packed sea bass. Total viable counts of fried, baked and microwave-cooked sea bass reached 6.06, 7.00, 7.24 log cfu/g, respectively, after 15 days. On day 15, the total volatile base nitrogen (TVB-N) value of microwave-cooked sea bass exceeded the allowable limit of 38.72 mg/100 g, whereas the TVB-N value of fried and baked sea bass reached 22.46 and 29.85 mg/100 g, respectively. Therefore, it can be concluded that frying at 180C for 5 min in core is the most effective cooking method to ensure the safety and extend the shelf life of fried sea bass, preserving its microbiological guality.

PRACTICAL APPLICATION

This study establishes the chemical, microbiological and sensory quality of vacuum-packed sea bass and emphasizes the relevance of the quality changes of the different cooked sea bass. Heat treatments and storage temperatures are very important to ensure the safety of the fish product.     

Formation of trans fatty acids in edible oils during the frying and heating process

To assess an impact of heated edible oils on intake of trans fat, the formations of trans fatty acids (TFAs) in cooking conditions was estimated by a frying and heating model system. For the frying model, sliced raw potatoes (10% of the frying oil (w/w)) were fried in commercially available canola oil at 160, 180 and 200 °C, and the 10 frying cycles were performed. The TFAs contained both in fried potatoes and in frying oils were measured by gas chromatography (GC). Lipids content of raw potatoes was about 0.1% (w/w) and TFAs in the raw potatoes were negligible. On the other hand, fried potatoes contained lipids at the level of 8.8%–9.2% and their fatty acid composition was mostly in correspondence with that of the frying oil. The TFAs amount of potatoes fried by the tenth frying operation was at the level of 0.99–1.05 g/100 g lipids. When 100 g potatoes fried in this process were consumed, the TFAs intake was estimated at less than 0.1 g. After 10 frying operations, TFAs content, acid values and peroxide values of the frying oils were measured and compared with those of corresponding heated canola oils without food. The amounts of trans 18:1 FAs contained both in the frying oil and in heated oil were less than the quantitative limit (0.047 g/100 g oil). The increases of trans 18:2 FAs and trans 18:3 FAs of the used frying oil were 0.02 g/100 and 0.05 g/100 g, respectively, compared with those of the fresh oil. trans 18:2 FAs accumulation in the heated oil was slightly less than that in the frying oil. To elucidate TFAs accumulation in various edible oils during cooking, six kinds of commercially available edible vegetable oils were heated to 180 °C in glass test tubes. Small changes in TFAs amounts were observed after four hours heating. These results suggested that an ordinary frying process using unhydrogenated edible oils has little impact on TFAs intake from edible oils.     

Effect of different cooking methods on lipid oxidation and formation of volatile compounds in foal meat

The influence of four different cooking methods (roasting, grilling, microwaving and frying) on cooking loss, lipid oxidation and volatile profile of foal meat was studied. Cooking loss were significantly (P < 0.001) affected by thermal treatment, being higher (32.5%) after microwaving and lower after grilling (22.5%) and frying (23.8%). As expected, all the cooking methods increased TBARs content, since high temperature during cooking causes increased oxidation in foal steaks, this increase was significantly (P < 0.001) higher when foal steaks were microwaved or roasted.     

Chemical and biochemical characterisation of an IGP ecotype chestnut subjected to different treatments

This study investigated and compared the polyphenols content, the antioxidant activity, the mineral and trace elements concentrations of raw chestnuts, chestnuts subjected to different cooking methods and cured chestnuts. The aim was to verify the quality of raw fruit and the changes induced from treatments, such as roasting, boiling and curing. The total polyphenol content and the antioxidant activity decreased in cured and heat-treated chestnuts, when compared to raw material, in the following order: cured > roasted > boiled shelled > boiled unshelled fruits. Specific phenolic compounds showed significant effects of cooking treatments, while the concentrations of minerals (Ca, K, Mg, and Na) and trace elements (As, Cd, Cu, Fe, Hg, Mn, Ni, Pb and Zn) also varied.     

Heavy metal levels in two fish species Leuciscus cephalus and Lepomis gibbosus

The concentrations of heavy metals (Cd, Co, Cu, Fe, Mn, Ni, Pb, Zn) were measured in muscle, gill and liver of two fish species (Leuciscus cephalus and Lepomis gibbosus) caught from Saricay, South-West Anatolia. Levels of metals varied depending on different tissues in species. The mean concentrations (μg g⁻¹ wet weight) of heavy metals in tissues of Leucis cephalus were as follows: Cd: 0.010–0.084, Co: nd–0.131, Cu: 0.193–2.611, Fe: 4.240–172.000, Mn: 0.112–24.230, Pb: 0.068–0.874, Zn: 6.350–28.550, and in tissues of Lepomis gibbosus were as follows; Cd: 0.008–0.082, Co: nd–0.233, Cu: 0.065–4.360, Fe: 11.200–125.000, Mn: nd–12.434, Pb: 0.070–0.920, Zn: 6.540–16.064. Ni was not determined in all organs studied.     

Minor and trace elements in different honey types produced in Siena County (Italy)

The concentrations of 23 chemical elements (Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, Mg, Mn, Na, Ni, Pb, Sb, Se, Sr, Th, Tl, U, Zn) were determined in 51 honey samples of different botanical origin produced in Siena County (Italy). K, Ca, Na and Mg were the most abundant elements, with mean contents of 1195, 257, 96.6 and 56.7 mg/kg, respectively. The Fe, Zn and Sr contents generally ranged from 1 to 5 mg/kg. Except for Ba, Cu, Mn and Ni, the trace element contents were below 100 μg/kg. The analytical data indicated a good level of quality of the honeys, especially with regard to the concentrations of toxic trace elements, such as As, Cd, Pb and Sb, and suggested a significant influence of the botanical origin on the element composition. Some local geological and geochemical features also seemed to affect the chemistry of the honey.     

Lipid characteristics in cooked, chill-reheated fillets of Indo-Pacific king mackerel (Scomberomorous guttatus)

Slices of Scomberomorous guttatus cooked by four different methods (microwave cooking, grilling, steaming and shallow fat frying) were kept chilled at 5 °C for 2 days, reheated by microwave and then evaluated for the changes in the lipid characteristics. The total lipid content for raw sample was 6.0 g/100 g which consist of 49.4 g/100 g saturated (SFA), 6.9 g/100 g monounsaturated (MUFA) and 43.8 g/100 g polyunsaturated fatty acids (PUFA). Upon cooking, the total lipids changed to about 7 (microwave), 11 (grilling), 5 (steaming) and 10 g/100 g (shallow fat frying). These changes are significant, with the exception of steam cooking. Cooking did not significantly affect the percentage of NPL, PL, SFA, MUFA and PUFA in the samples. Frying resulted in the change of the SFA/PUFA ratio more than other cooking methods. A significant (P < 0.05) decrease in the content of EPA was only found in the fried samples. A significant (P < 0.05) decrease in the content of DHA in all cooked samples were also obtained. The n-6/n-3 ratio did not change significantly in all cooked and reheated samples, except for shallow fat fried. Reheating did not significantly affect the NPL and PL contents of the fillets, except for microwave cooked samples. Cooking increases the FFA, PV and TBA of samples; reheating enhances the increase.     

Assessment of concentrations of toxic elements in aquaculture food products in Malaysia

Thirteen species of aquaculture food products, including fresh water and marine fish, prawns, and seaweed were collected from 37 aquaculture farms in Malaysia. Muscle and liver specimens from these species were tested for the presence of As, Cd, Cr, Cu, Hg, Pb, and Zn by using a heat vaporisation atomic absorption spectrophotometer and an inductively coupled plasma atomic emission spectrophotometer. Sea bass from each collected site were comparatively studied, where As concentrations were assumed to be caused by different culture system; and, Hg and Pb concentration were assumed to be due to anthropogenic activities in specific sites. The calculated estimated intake values of Malaysians for total As, Cd, Cr, Cu, Hg, Pb, and Zn in the muscle of the examined species were 3.713, 0.115, 0.113, 4.268, 0.211, 0.738 and 15.863 μg/kg b.w./day. None of the values exceeded the JECFA guideline values and would pose no health hazards for consumers.     

Assessing the quality of organic and conventionally-farmed European sea bass (Dicentrarchus labrax)

The biometric and nutritional traits of European sea bass from organic or semi-intensive conventional production systems at two commercial sizes (small and medium) were compared. The analysis included a total of 80 specimens. The biometric traits and the texture were not affected by the rearing system, whereas they changed significantly with fish size. The fillet fatty acid profile varied significantly, both with rearing system and sea bass size, depending on the fatty acid profile of the diets. The ratio of n − 3 to n − 6 polyunsaturated fatty acids was higher (p < 0.001) in organic than in conventional fish (1.60 vs. 0.54) and in small than in medium-sized sea bass (1.15 vs. 0.98). Near infrared reflectance spectroscopy (NIRS) successfully classified fillets according to sea bass size in both fresh-minced and freeze-dried samples (90% correct classification), whereas it only classified organic vs. conventional sea bass fairly well (65-75% correct classification) for freeze-dried fillets.     

Safety evaluation of the metals in some brands of nail polish in Nigeria

This article shows the concentrations of ten metals (Cd, Pb, Ni, Cr, Cu, Co, Fe, Mn, Zn and Al) measured in 30 different brands of nail polish in the Nigerian market in order to provide some relevant information on the safe levels of these products for consumers. The metal concentrations in the nail polish samples ranged from <0.15 µg/g Cd, <0.03 to 7.25 µg/g Pb, <0.03 to 40 µg/g Ni, <0.1 to 8.25 µg/g Cr, <0.03 to 590 µg/g Cu, <0.03 to 3.00 µg/g Co, <0.1 to 15,200 µg/g Fe, <0.05 to 458 µg/g Mn, <0.03 to 595 µg/g Zn and <0.25 to 13,600 µg/g Al. The concentrations of Ni, Cr, and Co were found above the suggested allergenic limit of 1 µg/g in 56, 33 and 17 % of the 30 brands, respectively, whereas Cd and Pb were detected at levels below their permissible limits as impurities in cosmetics as specified by Health Canada. The brands made in Nigeria contained lower concentrations of Ni, Cr, Cu, Co, Pb and Al than the imported brands.     

贵州喀斯特地区土壤-辣椒体系重金属元素的生物迁移积累特征

采集喀斯特地区(遵义虾子与贵阳花溪)的辣椒及种植土壤样品,利用电感耦合等离子体质谱仪和电感耦合等离子体原子发射光谱仪检测辣椒和土壤中13种重金属元素(As、Cd、Pb、Hg、Cr、Cu、Zn、Ni、Tl、Co、Sb、Sn、Mn)的含量,探讨土壤-辣椒体系重金属元素的生物迁移积累特征。结果表明:与HJ/T 332—2006《食用农产品产地环境质量评价标准》相比,土壤中Cd平均含量超标了9.33%,点位超标率为57.89%。与GB 2762—2012《食品中污染物限量》相比,遵义地区辣椒中Cd含量部分超标,超标率为85.71%,花溪地区2个辣椒样品Cr含量超标,分别超标了15.36%和12.18%。辣椒的13种重金属生物富集系数大小顺序为CdCuZnHgSnTlMnSbNiCoCrAsPb,辣椒Cd的生物富集系数为1.138,Pb的生物富集系数为0.001 9。辣椒中Co、Ni、Sn含量与土壤对应金属含量呈显著正相关(P0.05),其余重金属含量与土壤对应元素含量无显著相关性(P0.05)。食用辣椒途径的Cd和Cr每周重金属摄入量远小于世界卫生组织提出的专门针对敏感人群临时性每周人体可耐受摄入量,辣椒Cd、Cr超标不会对人体健康造成影响。在贵州喀斯特Cd高背景值地区种植辣椒应注重辣椒对Cd的富集。     

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. Copyright © 2011 Society of Chemical Industry     

Study on heavy metals levels and its risk assessment in some edible fishes from Bangshi River,Savar, Dhaka,Bangladesh

Concentrations of eight heavy metals (Pb, Cd, Ni, Cr, Cu, Zn, Mn, and As) in the muscles of ten species of fish collected from Bangshi River at Savar in Bangladesh were measured in two different seasons. The concentrations of the studied heavy metals, except Pb in Corica soborna, were found to be below the safe limits suggested by various authorities and thus gave no indication of pollution. The present study also showed that, Zn was the most and Cd was the least accumulated metal in the studied fish muscles. ANOVA analysis clearly revealed that there was a significant variation (CI = 95%) of the heavy metal concentrations in different fish species in the Bangshi River. Significant positive correlations between the heavy metal concentrations in fish muscles were also observed in both seasons. From the human health point of view, this study showed that there was no possible health risk to consumers due to intake of studied fishes under the current consumption rate.     

Effect of cooking method on the fatty acid profile of New Zealand King Salmon (Oncorhynchus tshawytscha)

Farmed New Zealand King Salmon (Oncorhynchus tshawytscha) was prepared according to common consumer techniques; raw, poached, steamed, microwaved, pan fried (no added oil), oven baked (no added oil) and deep fried (in sunflower oil). The fatty acid profile was investigated to determine the optimal preparation techniques to achieve both optimal sensory and nutritional qualities, in particular the levels of long chain polyunsaturated omega-3 fatty acids. The modified Bligh and Dyer method was used for lipid extraction and the Hartman and Lago method for FAMES preparation. Fatty acid composition was determined by gas chromatography. There were moisture and lipid losses during cooking amongst the different methods. The fatty acid profile showed only minor differences between the methods apart from an increase in PUFA in the deep fried salmon due to linoleic acid uptake from the frying oil. In all the cooking methods the omega-3 fatty acids were well preserved. However, deep fried showed the lowest amounts of omega-3 fatty acids. As the results showed good preservation of omega-3 fatty acids regardless of cooking method, there may be possible “internal protection” of omega-3 fatty acids in King Salmon that warrants future research.     

N-Nitrosothiazolidine and N-Nitrosothiazolidine-4-Carboxylic Acid in Smoked Meats and Fish

Various smoked meats including raw and fried bacon and both unsmoked and smoked (uncured) fish were analyzed for NThZ and NTCA. Most meat samples, bacons, and a few smoked fish contained traces of NThZ and considerably high (up to 13,700 ppb) levels of NTCA. Preliminary results indicated that raw bacons processed by old-fashioned direct smoking methods contained the highest (> 1,000 ppb) level of NTCA. Formation of NThZ from the NTCA present in smoked bacon increased with an increase in frying temperature as well as with frying time. NTCA level in the raw bacon and the cooking conditions seemed to be the most important factors involved in the formation of NThZ in the fried bacon. The reason for finding only insignificant levels of NThZ in smoked fish could not be established conclusively.     

Effect of boiling and frying on the content of essential polyunsaturated fatty acids in muscle tissue of four fish species

Frozen samples of common fish species, sea trout (Salmo trutta), from Norway and Siberia, herring (Clupea harengus pallasi), rock sole (Lepidopsetta bilineata) and cod (Gadus morhua maris-albi), collected from a wholesale market in Krasnoyarsk city (Siberia, Russia) were analyzed. Special attention was paid to long-chain essential polyunsaturated fatty acids: eicosapentaenoic, 20:5ω3 (EPA) and docosahexaenoic, 22:6ω3 (DHA). Heat-treatment (cooking and frying) did not in general significantly decrease the contents of EPA and DHA compared to raw fish species, except for a modest reduction in Norwegian trout during frying. Boiled trout appeared to be a more valuable fish dish for obtaining the officially recommended appropriate daily intake of EPA + DHA for humans. Herring and sole had intermediate values, while boiled cod had a comparatively low value.     

Mineral composition of edible seaweed Porphyra vietnamensis

Edible seaweed Porphyra vietnamensis growing along seven different localities of the Central West Coast of India was analyzed for mineral composition (Na, K, Ca, Mg, B, Pb, Cr, Co, Fe, Zn, Mn, Hg, Cu, As, Ni, Cd and Mo) by inductively coupled plasma atomic emission spectroscopy (ICP-AES). The concentration ranges found for each sample, were as follows: Na, 24.5–65.6; K, 1.76–3.19, Ca, 1.40–6.12; Mg, 4.0–5.90 (mg/g d wt); Pb, 0.01–0.15; Cr, 0.13–0.22; Co, 0.06–0.20; Fe, 33.0–298; Zn, 0.93–3.27; Mn, 4.22–10.00; Hg, 0.01–0.04; Cu, 0.54–1.05; As, 1.24–1.83; Ni, 0.02–0.25; Cd, 0.14–0.55; Mo, 0.02–0.03 and B, 0.02–0.07 expressed in mg/100 g dry weight. Mineral composition of P. vietnamensis was found relatively higher as compared to the land vegetables as well as to other edible seaweeds, and it is in concurrence with the recent macrobiotic recommendation for western countries. It could therefore be used as food supplement as a spice to improve the nutritive value in the omnivorous diet.