Thermal characteristics of flaxseed (Linum usitatissimum L.) proteins

Thermal characteristics of ion-exchange protein fractions from dehulled delipidated meal of four flaxseed cultivars grown at three locations were evaluated by differential scanning calorimetry (DSC) to examine genotypic and environmental effects. DSC was performed in a “dry” state on four, 0.28, 0.35, 0.45 and 0.50 M NaCl lyophilized protein fractions. Flaxseed proteins exhibited two thermal events between 83 and 115 °C with distinct shoulders present in the 0.45 and 0.50 M fractions of all cultivars. Cultivar and location effects were significant for the first thermal transition (_Td1$T_{{\mathrm{d}}_1}$) of the 0.28 and 0.35 M fractions, and the second transition (_Td2$T_{{\mathrm{d}}_2}$) of the 0.35, 0.45 and 0.50 M fractions. The enthalpy of the first transition ΔH₁ of the 0.35 and 0.50 M fractions was cultivar dependent, while that of the second transition ΔH₂ was cultivar and location specific for the 0.35, 0.45 and 0.50 M fractions. The 0.28 and 0.45 M fractions displayed the lowest and highest thermal transition temperatures, respectively. All protein fractions consisted of reversing and nonreversing thermal events as assessed by modulated DSC. Flaxseed cultivars, when grouped by thermal characteristics of protein fractions, can be differentiated by principal component analysis.     

FASS法测定苗族传统食品鱼酱酸中的锌、铜、镉、铅含量

对传统鱼酱酸及银鱼鱼酱酸中的锌、铜、镉、铅进行测定.以FASS法测定样品中的锌、铜、镉、铅,通过正交试验优化仪器最佳工作条件,采用湿法消解样品.传统鱼酱酸和银鱼鱼酱酸中锌的含量分别是5.7794mg/kg和4.4834mg/kg,铜的含量分别是0.7224mg/kg和1.2808mg/kg,2种鱼酱酸均未检出镉和铅.FASS法测定鱼酱酸锌、铜、镉、铅操作简便,灵敏度较高,检出限较低;鱼酱酸中有较高含量的锌和一定含量的铜,是具有较高营养价值的发酵调味品.     

Contents of macro and microelements in fresh and frozen dill (Anethum graveolens L.)

The level of ash and its alkalinity and the contents of potassium, sodium, magnesium, iron, phosphorus, zinc, copper, cadmium, and lead, were determined in green dill (leaves and whole plants, about 20 cm in height, harvest time). The two usable parts were frozen using variable pretreatments (blanching or no blanching) and different storage temperatures (−20 and −30 °C). Analyses were conducted after 0, 3, 6, 9, and 12 months of refrigerated storage. Fresh leaves contained more ash, magnesium, iron, phosphorus, zinc, cadmium and lead but less sodium and copper than whole plants, while the contents of potassium and calcium were similar. Blanching significantly reduced the level of ash and its alkalinity and of potassium, calcium, magnesium, phosphorus, zinc, copper, cadmium, and lead, both in the usable parts of the plant, and of sodium in whole plants and of iron in leaves. During the storage period, changes in the contents of the analysed constituents did not depend on the usable part or storage temperature, being statistically significant only for the contents of iron and copper in the two usable parts of frozen non-blanched dill.     

Molecular basis of cadmium toxicity

Cadmium has been shown to manifest its toxicity in human and animals by mainly accumulating in almost all of the organs and kidney is the main target organ where it is concentrated mainly in cortex. Environmental exposure of cadmium occurs via food, occupational industries, terrestrial and aquatic ecosystem. At molecular level, cadmium interferes with the utilization of essential metals e.g. Ca, Zn, Se, Cr and Fe and deficiencies of these essential metals including protein and vitamins, exaggerate cadmium toxicity, due to its increased absorption through the gut and greater retention in different organs as metallothionein (Cd-Mt). Cadmium transport, across the intestinal and renal brush border membrane vesicles, is carrier mediated and it competes with zinc and calcium. It has been postulated that cadmium shares the same transport system. Cadmium inhibits protein synthesis, carbohydrate metabolism and drug metabolizing enzymes in liver of animals. Chronic environmental exposure of cadmium produces hypertension in experimental animals. Functional changes accompanying cadmium nephropathy include low molecular weight proteinuria which is of tubular origin associated with excess excretion of proteins such as beta 2 microglobulin, metallothionein and high molecular weight proteinuria of glomerular origin (excretion of proteins such as albumin IgG, transferrin etc.). Recent data has shown that metallothionein is more nephrotoxic to animals. Cadmium is also toxic to central nervous system. It causes an alterations of cellular functions in lungs. Cadmium affects both humoral and cell mediated immune response in animals. Cadmium induces metallothionein in liver and kidney but under certain nutritional deficiencies like protein-calorie malnutrition and calcium deficiency, enhanced induction and greater accumulation of cadmium metallothionein has been observed.     

Effects of geographical origin and variety on vitamin and mineral composition of hazelnut (Corylus avellana L.) varieties cultivated in Turkey

The effects of variety and geographical origin on vitamin and mineral composition of eight different varieties of hazelnut cultivated in the Black Sea Region of Turkey were studied. The mean contents of niacin, vitamin B₁, vitamin B₂, vitamin B₆ and α-tocopherol were 1.81±0.28, 0.30±0.07, 0.10±0.01, 0.240±0.05, and 35.53±3.82 mg/100 g, respectively. The mean contents of iron, zinc, copper, magnesium, manganese, calcium, potassium and sodium were 2.32±0.21, 1.95±0.25, 0.65±0.29, 144±14.86, 6.09±4.17, 83.5±5.14, 637±105.33 and 0.70±0.10 mg/100 g, respectively. Vitamin and mineral compositions of the varieties were not significantly different from each other. Geographical region differences did not significantly affect α-tocopherol, iron, manganese and calcium contents of the samples. Zinc, manganese, and sodium levels of Akçakoca samples were higher than for the other regions. Correlation analysis showed that α-tocopherol content correlated strongly with minerals (manganese, sodium, zinc, potassium) and vitamin B₆.     

Cadmium, lead, and zinc-content of fruits and vegetables from gardens in industrial region (author's transl)]

The contents of Cadmium, lead, and zinc in 136 samples of fruit and vegetable of harvest 1973, taken from gardens in Dortmund, have been analysed by mineralisation, extraction with APDC/MIBK and AAS. 5% of the samples contained more cadmium, 13% more lead and zinc than proposed limits.     

Determination of Cd,Cu, and Zn in fish and mussel by AAS after ultrasound-assisted acid leaching extraction

An ultrasound-assisted solid–liquid extraction procedure by using diluted mixed acid solution was developed for determination of cadmium, copper and zinc in fish and mussel samples. The effects of several parameters such as nitric acid concentration, hydrochloric acid concentration, hydrogen peroxide concentration, leaching solution volume, and sonication time have been investigated. A 30-min sonication, 56 °C operating temperature and 6 mL of 1:1:1 HNO₃(4 M):HCl(4 M):H₂O₂(0.5 M) were used for 0.5 g of dried sample. Cadmium and copper were determined by graphite furnace atomic absorption spectrometry, and zinc was determined by flame atomic absorption spectrometry. The results obtained from the proposed procedure were evaluated by comparison with the results obtained by microwave-assisted digestion. Ratio (%) of metal amount obtained from leaching technique to amount obtained from digestion technique for cadmium, copper and zinc ranged from 92% to 114% for fish and from 88% to 103% for mussel samples. The MDL were 0.02, 0.13 and 0.63 mg kg⁻¹ for cadmium, copper and zinc, respectively. The accuracy of the developed method was investigated by analyzing a dogfish muscle certified reference material (DORM-2). Recoveries were obtained in the order of 80.9 ± 0.3 and 87.2 ± 0.6%.     

Cadmium, mercury, iron, copper, manganese and zinc in the liver and kidney of the Icelandic lamb

The purpose of this study was to evaluate the levels of cadmium, mercury, iron, copper, manganese and zinc in lamb liver and kidney from six areas in Iceland and to compare the results against aerial deposition data for the same elements obtained using moss as an indicator organism. The total number of samples was 96 for each organ. Cadmium was determined by graphite furnace atomic absorption spectrophotometry, mercury by coldvapour atomic absorption, and iron, copper, manganese and zinc by inductively coupled plasma atomic emission spectrophotometry. Analysis of variance determined significance differences among means for areas, and Pearson's correlation coefficients were calculated to study correlation among trace elements in liver and kidney. The mean fresh weight concentrations in lamb liver and kidney respectively were 0.045 and 0.058mg kg -1 for cadmium, 0.009 and 0.012mgkg -1 for mercury, 141 and 52.7mgkg -1 for iron, 28.1 and 2.89mgkg -1 for copper, 4.01 and 1.13mgkg -1 for manganese and 48.7 and 25.2mgkg -1 for zinc. Concentrations of cadmium, mercury and copper in the liver and kidney of the Icelandic lamb were low compared with data from other countries. Iron concentrations in the organs, however, were high. No sample exceeded 46% of the proposed maximum level for cadmium in organs for human consumption in the EC. Cadmium, mercury, iron and copper in the liver and kidney differed significantly between areas. Deposition of cadmium and copper in moss was not a useful indicator in the evaluation of the susceptibility of the Icelandic lamb to accumulation of cadmium and cop per. However, iron levels in Icelandic lamb liver showed the same pattern as results for iron from the moss study. The cadmium and mercury levels of organs from lambs grazing in the vicinity of Mount Hekla a few months after its eruption did not indicate a significant contamination from volcanic activity.     

Potentiometric stripping analysis of selected heavy metals in biological materials

Different biological materials such as edible oils, refined and unrefined cane and beet sugar and tea (black and green) leaves were assayed for the heavy metals cadmium, copper, lead and zinc. The results revealed significant differences in heavy metal contents within each class of the biological materials (P < 0.05). Cadmium was not detectable in sugar samples. Among the oils, highest amounts of copper (0.263 μg/g) and lead (0.154 μg/g) were in corn oil and zinc in olive oil (3.01 μg/g) whereas cadmium exhibited a narrow range (0.023–0.033 μg/g). The samples of beet-sugar generally contained higher levels of the heavy metals than cane-sugar. Black and green tea leaves contained 0.411–0.908 μg Cd/g, 6.500–9.220 μg Cu/g, 2.200–5.238 μg Pb/g, and 14.500–25.180 μg Zn/g.     

菲律宾蛤仔不同组分中重金属存在形态研究

为研究菲律宾蛤仔不同组分中重金属存在形态,将菲律宾蛤仔通过差速离心制备成细胞质、细胞核、线粒体三种组分,用逐级化学提取技术将不同存在形态的金属提取出来,采用原子发射光谱法测定了三种组分中铅、锌、镉三种重金属总含量以及不同存在形态的含量,并计算逐级化学提取技术对重金属的回收率。结果表明:铅和镉元素在细胞质中含量最高,锌元素主要存在于细胞核和线粒体中。铅元素主要以硫化物结合态存在于细胞核、细胞质、线粒体中,硫化合物结合态含量分别占各组分铅元素总含量的75.24%、71.29%和50.71%;锌以残渣态在细胞核中的含量最高,残渣态含量占细胞核中锌总量的34.51%,细胞质中锌主要以可交换态存在,可交换态含量占细胞质中锌总量的35.21%;镉在各组分中主要以有机物结合态、硫化物结合态、可交换态三种状态存在。采用逐级化学提取技术测定菲律宾蛤仔不同组分中重金属铅、锌、镉存在形态的回收率为50.71%~99.08%,其中镉元素回收率最高,在三种组分中均达到93%以上。综上,菲律宾蛤仔细胞质中铅、锌、镉三种金属多以硫化物结合态和可交换态存在,这两种形态的金属易于释放到环境中;细胞核、线粒体中锌、镉两种元素主要以残渣态和有机物结合态存在,这两种形态的金属相对稳定。     

CHARACTERIZATION OF PHYTOCHELATIN-LIKE COMPLEXES FROM FLAX (LINUM USITATISSIMUM) SEED

Proteins were extracted from dehulled and delipidated powder of flaxseed (cv. NorMan), and fractionated by DEAE‐Sephacel onion exchange chromatography. Ultraviolet absorbance scans of ion exchange fractions eluting in buffers at pH 8.6 containing 0.45 M and 0.50M NaCl revealed A₂₅₅ >A₂₈₀. Furthermore, the A₂₅₅ was reduced upon acidification and restored by adjusting to the original pH, confirming spectral characteristics typical of metal‐thiolate complexes. Characteristic circular dichroism spectra and reversible aggregation‐dissociation behavior under low and high salt conditions observed for these fractions are also typical of metal binding phytochelatins reported for other plants, while the presence of aromatic amino acids indicated by fluorescence spectra suggests some similarity to nonmetallothionein proteins. Further work is underway to investigate the prevalence of these and other complexes as well as the distribution of metals in different protein fractions of flaxseed, as a function of cultivar and geographical location.     

Lead and cadmium levels in commercial infant foods and dietary intake by infants 0-1 year old

Lead and cadmium levels were determined in 131 infant foods. Mean lead and cadmium levels were 19.3 and 3.3 ng/g for meats, 8.4 and 4.1 ng/g for vegetables, 14.9 and 0.58 ng/g for fruits and desserts, 9.6 and 0.53 ng/g for juices and drinks, and 32.8 and 33.6 ng/g for dry infant cereals. These data, combined with those from other recent surveys, yielded average dietary (food and water) intakes of lead and cadmium by infants 0-1 year old of 2.4 and 0.37 microgram/kg/day, respectively. Lead intakes were most strongly influenced by storage of infant formulas in lead-soldered cans. For infants 0-1 month old, they ranged from 0.5 microgram/kg/day when human or cow milk was fed to infants to 5.3 micrograms/kg/day (exceeding the FAO/WHO provisional tolerable daily intake, PTWI, of lead by children of 3.5 micrograms/kg) when ready-to-use formula stored in lead-soldered cans was fed. Cadmium intakes were most strongly affected by soya based formulas, and ranged, for 0-1 months olds, from 0.16 microgram/kg/day for infants fed human or cow milk to 0.50 microgram/kg/day for infants fed soya-based concentrated liquid formula. Cadmium intakes were all below the FAO/WHO PTDI of cadmium by adults of 0.96-1.2 micrograms/kg.     

Survey of lead, cadmium, iron, copper and zinc in Ka?ar cheese.

Lead, cadmium, iron, copper and zinc contents of Ka?ar cheese sold in the markets of Ankara, Turkey, were determined over 12 months. A total of 240 samples comprising 10 different brands were analysed. Graphite-furnace atomic absorption was employed for the determination of lead and cadmium, and flame atomic absorption for iron, copper and zinc. The mean (range) of the lead, cadmium, iron, copper and zinc content of the samples were 86 (10-421) microg kg(-1), 1.8 (0.3-8.3) microg kg(-1), 4.2 (1.0-14.1) mg kg(-1), 0.7 (0.3-1.6) mg kg(-1) and 37.7 (26.5-63.0) mg kg(-1), respectively. The samples in November, December and January contained higher amounts of lead than those in other months (p < 0.01). Moreover, important differences existed in lead content of the samples between different cheese producers (p < 0.01). The differences in cadmium and iron content of the samples for different months were important (p < 0.01). The iron content of the samples among manufacturers also varied significantly (p < 0.01). However, there were no significant differences in copper and zinc contents of the samples over 12 months (p > 0.05). These findings suggested that some contamination occurred during milk production and/or manufacturing of cheese depending on the equipment used. For a consumption of 100 g Ka?ar cheese, one would ingest approximately 8.6 microg (4% of the provisional tolerable daily intake, PTDI) of lead, 0.2 microg (0.3%) of cadmium, 0.4 mg (0.9%) of iron, 0.07 mg (2%) of copper and 3.8 mg (6%) of zinc. Therefore, it was concluded that Ka?ar cheese is not a significant contributor to the intake of investigated heavy metals.     

Zinc,copper, lead and cadmium contents in green tea

The levels of zinc, copper, lead and cadmium in green tea have been determined by atomic absorption spectrophotometry. With the growth and development of tea shoots, zinc, copper, lead and cadmium concentrations decreased gradually. Some of the lead in green tea was eliminated by washing with water before manufacturing. The range and mean of the zinc, copper, lead and cadmium in 139 green teas were as follows: zinc, 23.4–100.5 and 54.4 μg/g; copper, 4.7–36.5 and 11.4 μ/g; lead, 0.11–1.93 and 0.49 μg; cadmium, 0.013–0.098 and 0.036 μg/g. Significant differences in the contents of copper and lead were observed among the different districts of the country. The green tea produced in some districts near the metropolis areas contained the highest concentration of lead.     

Results of a dynamic study on the status of health and nutrition of a Siberian vegan settlement

In 1996 for the first time a study of state of health, living conditions and nutrition status of 84 persons from the Siberian settlement of the rigorous vegetarians--vegans and 26 aboriginal inhabitants who feed on a traditional mixed diet was carried out. The clinical and laboratory investigations are kept. The positive influencing vegan ration on a serum lipids, body weight, state of cardiovascular system was showed. The contents of vitamin B12 and serum iron in vegans was in normal physiological range. The level of blood calcium was reduced in comparison with control. Increased contents of copper and zinc in blood was marked both in vegans and in control group. The repeated examination of 77 vegans of the same settlement in 1999 has revealed positive alterations in serum lipids: augmentation of cholesterol of high density lipoproteins on the average on 54.3%, that result in a reliable decrease of atherogenicity coefficient. The decrease to normal amounts of blood copper and zinc, and also increase of blood calcium on the average on 16% was marked. However level of calcium remained below than physiological values.     

不同浓度海水灌溉对库拉索芦荟中微量元素的影响

采用原子吸收分光光度法分析了不同浓度海水灌溉的3年生库拉索芦荟中Ca、Mg、Na、K、Mn、Zn、Fe、Cu、Ni、Pb、Cd、Cr共12种微量元素的含量。试验发现:各元素在芦荟中的含量差异较大,其中,Ca、Mg、Na、K含量丰富,Mn、Zn、Fe含量中等,而有毒重金属离子Cu、Ni、Pb、Cd、Cr含量很低;无论是凝胶还是全叶中,海水浓度对库拉索芦荟中Ca、Mn元素的影响很大,对其他各种元素的影响不大,但Cd离子的含量随海水灌溉浓度的升高呈略微上升趋势。     

Seasonal variations in proximate and elemental composition of pearl oyster (Pinctada radiata,Leach, 1814)

Pearl oysters (Pinctada radiata) were investigated for proximate and elemental composition throughout the year. Oysters were collected bimonthly by hand during scuba diving from the Gulf of Antalya. Ranges of dry matter, protein, fat and ash contents were 144.7–209.8, 65.9–160.4, 4.3–10.9 and 4.6–27.0 g kg^?1, respectively. While the highest protein and fat values were found in the summer months, the highest dry matter and ash contents were found in the winter months. The highest element contents were found in the spring and autumn months. Cadmium and zinc were found to be over the legislative limits, while copper was below, throughout year. The highest concentration among the elements was obtained for zinc. Copyright © 2006 Society of Chemical Industry     

Concentrations of heavy metals in the tissues of red deer (Cervus elaphus) from the region of Warmia and Mazury, Poland.

Cadmium, lead, copper and zinc were quantified using a validated ICP/MS method in the tissues and organs of 82 specimens of red deer of different sexes and ages, which had been hunted at the Great Lakes Land region in the north-eastern of Poland in 2000-01. Copper and zinc occurred in liver, kidney and muscle tissue of red deer at concentrations of 6.4-29, 3.3-7.2 and 1.9-6.4, and of 19-43, 17-41 and 19-64 mg kg(-1), respectively, which are considered typical for the species, age and gender compared with values noted for some other wild and domestic ruminant species elsewhere. For cadmium and lead, the concentrations decreased in the order kidney > liver > muscle tissue, with overall means of 2.2, 0.19, and 0.10, 0.31, and 0.26, 0.22 mg kg(-1) wet weight, respectively. The cadmium content of the kidney of a proportion of red deer sampled exceeded the legal tolerance limits set in Poland. The means (but not individual animal data) obtained for cadmium in kidney and liver correlated (0.99) with the age of red deer. Also, the lead content of the muscle meat of red deer for many carcasses exceeded the legal limit, which was probably due to contamination from the fine dust particle remains from the lead bullets used.     

惠州市售猪肉和猪肝中重金属元素残留的抽检检测报告分析

本文采用湿法消解,原子吸收火焰法测定猪肝中的铜,原子吸收石墨炉法测定猪肝中的镉和铬;采用干法灰化,原子吸收火焰法测定猪饲料中铜含量.通过对惠州地区市售的猪肝(30份)和猪肉(30份)进行检测,发现猪肝和猪肉中的镉含量为0.01～0.16mg/kg,铬含量为0.10～0.88 mg/kg,合格率均为100％;猪肝中铜含量为4.90～78.9 mg/kg,合格率仅为50.0％.猪肉中铜含量为0.23～0.87mg/kg,合格率为100％;生长育肥猪后期配合饲料中铜含量0.29～69.0 mg/kg,合格率95.0％.调查表明惠州地区市售猪肉中铜、镉和铬元素残留量合格,猪肝中镉、铬残留量合格,铜残留量较高;市售育肥后期猪饲料中存在铜严重超标的现象.     

罗平土壤及烟叶主要中、微量元素含量分析

为了解云南罗平县植烟土壤和烤烟烟叶主要中、微量元素含量情况,测定了罗平县369个土壤和对应C3F等级烟叶的钙、镁、硫、铜、锌、铁、锰和硼含量,并评价了丰缺状况,分析了两者之间的关系。结果表明,罗平土壤中钙、镁、铜、锌、铁和锰含量普遍处于丰富和很丰富的水平,而硫和硼含量相对较低,普遍处于缺和很缺的水平,罗平土壤中有效中、微量元素存在空间上的广泛变异;烤烟生产上应适当增施硼肥。烟叶中硫、铜、锌和锰含量的平均值在适中范围内,铁含量较高,钙、镁和硼含量较低。土壤中有效中、微量元素的含量对烟叶中相对应的中、微量元素有促进作用。土壤中交换性镁对烟叶多种中、微量元素有促进或抑制作用,有效铜表现出了对锌的促进作用和对硼的抑制作用。