Availability of essential trace elements in Indian cereals,vegetables and spices using INAA and the contribution of spices to daily dietary intake

Indian diet is primarily vegetarian and consists of various cereals and vegetables along with spices, often used in the preparation of curries. The nutritive potential of each ingredient, in terms of trace element contents, has been evaluated using instrumental neutron activation analysis (INAA). Four minor (Na, K, P and Cl) and 16 trace elements (Br, Co, Cr, Cs, Cu, Fe, Hg, Mn, Mo, Rb, Sb, Sc, Se, Sr, Th and Zn) have been determined in six cereals, nine vegetables and 20 spices and condiments, including two betel leaves. None of the carbohydrate-rich cereals or potato was rich in any of the essential elements but leafy vegetables showed higher contents of Fe and other nutrients. Fe/Zn is well correlated with Fe contents in cereals and spices. Out of various spices, cinnamon was most enriched in Fe, Co, Cr, Na, K, P and Zn, whereas turmeric and curry leaves were found to be particularly rich in Se. Cumin and mustard seeds were rich in Cu. Some environmental contaminants, such as Hg, Cr, Br and Th, were also present in significant amounts. An attempt has been made to evaluate the contribution of essential elements (Cr, Cu, Fe, Mn, P, Se and Zn) in spices to the daily dietary intake (DDI) through an Indian vegetarian diet. For a typical mixture of six commonly used spices, contributions of Cr, Fe, Mn and Zn, were found to be 7.5% of DDI in each case.     

Comparative study of the mineral composition of several varieties of potatoes (Solanum tuberosum L.) from different countries cultivated in Canary Islands (Spain)

Potatoes are a basic component of human diets worldwide being an excellent source of minerals linked the maintenance of health. Contents of calcium (Ca), magnesium (Mg), potassium (K), sodium (Na), cupper (Cu), iron (Fe), manganese (Mn), zinc (Zn), nickel (Ni) and chromium (Cr) in seventy‐four fresh potato samples from different varieties consumed in Tenerife Island (Canary Islands, Spain) were determined by flame atomic absorption spetrometry (FAAS). The mean concentrations were 60.1 mg kg^?1, 222 mg kg^?1, 5047 mg kg^?1, 125 mg kg^?1, 1.69 mg kg^?1, 8 mg kg^?1, 1.70 mg kg^?1, 3.88 mg kg^?1, 62.7 μg kg^?1 and 19.9 μg kg^?1 for Ca, Mg, K, Na, Cu, Fe, Mn, Zn, Ni and Cr, respectively. The varieties of local potatoes presented higher mineral contents than imported potatoes. Potassium presented the highest contents in all varieties of potatoes. Iron was the most abundant microelement. Local potatoes offer greater nutritional contributions to the recommended intakes than imported varieties. Within the macrominerals, the highest contribution to the intakes was observed for K, while Fe was the trace element with the largest contribution to the proposed intake.     

Characterization and prediction by near-infrared reflectance of mineral composition of rocket (Eruca vesicaria subsp. sativa and Eruca vesicaria subsp. vesicaria)

BACKGROUND: Minerals are essential for human nutrition and must be obtained from our diet. Crucifer vegetables are a good source of these nutrients. Our objectives were to determine the genetic variability for mineral content and to evaluate the use of near‐infrared reflectance spectroscopy (NIRS) for prediction of ashes and minerals among and within the rocket species Eruca vesicaria subsp. sativa and vesicaria. The minerals studied were iron (Fe), copper (Cu), sodium (Na), potassium (K), calcium (Ca), magnesium (Mg), manganese (Mn) and zinc (Zn). RESULTS: The maximum mean values obtained for all the accessions (mean ± SE) were 235.5 ± 1.5 mg ashes kg^?1, 273.3 ± 4.2 mg Fe kg^?1, 18.1 ± 0.4 mg Cu kg^?1, 2.8 ± 0.1 g Na kg^?1, 71.6 ± 1.0 g K kg^?1, 64.6 ± 1.2 g Ca kg^?1, 6.8 ± 0.1 g mg kg^?1, 101.6 ± 1.2 mg Mn kg^?1, and 67.1 ± 0.4 mg Zn kg^?1 of dry weight. CONCLUSION: The statistical analysis showed significant differences for all the minerals, except Ca, for each accession studied individually and for accessions grouped within countries. The results indicate that NIRS can be used as a rapid screening method for determining total mineral, Fe, Na, K, and Zn in rocket. Copyright © 2011 Society of Chemical Industry     

Trace elements in edible tissues of three shrimp species (Penaeus semisulcatus,Parapenaeus longirostris and Paleomon serratus)

Accumulation levels of trace elements in edible tissues of three shrimp species (Penaeus semisulcatus, Parapenaeus longirostris and Paleomon serratus) from the Gulf of Antalya, Turkey were investigated. Copper (Cu), cadmium (Cd), zinc (Zn), iron (Fe) and manganese (Mn) concentrations were determined by atomic absorption spectrophotometry. The lowest Cu (1.33 mg kg^?1) and Cd (0.23 mg kg^?1) and highest Mn (1.52 mg kg^?1) concentrations were found in P. longirostris, the lowest Zn (6.25 mg kg^?1), Fe (1.84 mg kg^?1) and Mn (0.25 mg kg^?1) concentrations in P. serratus and the highest Cu (6.19 mg kg^?1), Cd (2.36 mg kg^?1), Zn (30.84 mg kg^?1) and Fe (33.89 mg kg^?1) concentrations in P. semisulcatus. The Cd levels detected in P. semisulcatus and P. serratus were above legislative limits. Our results show that there were significant differences in trace element concentrations among the three shrimp species. The highest levels of the five trace elements investigated, with the exception of Mn, were found in edible tissue of P. semisulcatus. Copyright © 2007 Society of Chemical Industry     

Heavy metals in vegetables sold in the local market in Jordan

Heavy metals (As, Cd, Co, Cr, Cu, Mn, Ni, Pb and Zn) in various vegetables (cabbage, green onion, lettuce, parsley, rocket, spinach, carrot, onion, potato and cauliflower) from the market in Jordan were measured using inductively coupled plasma-mass spectrometry. As, Cd, Co, Cr, Cu, Mn, Ni, Pb and Zn ranged from 0.009–0.275 mg kg^?1 wet weight, 0.004–0.060 mg kg^?1, 0.003–0.401 mg kg^?1, 0.105–3.51 mg kg^?1, 0.15–1.15 mg kg^?1, 0.93–14.39 mg kg^?1, 0.044–0.702 mg kg^?1, 0.072–0.289 mg kg^?1 and 2.23–6.65 mg kg^?1, respectively. Parsley, followed by spinach, contained the highest concentration of heavy metals. Onion contained high levels of toxic heavy metals. The content of Cu in parsley and spinach and Pb in onion exceeded the Codex limits. However, the daily intake of heavy metals from the tested vegetables was lower than the maximum limits for allowable intake.     

Elemental composition of commercial sea cucumbers (holothurians)

Toxic and essential elements in 11 different sea cucumber species were determined and compared with daily intake recommendations and maximum allowed levels. The contents of macro-elements contents in dried sea cucumber samples were found to be 25,000–152,000?mg?kg^–1 for Na, 4000–8600?mg?kg^?1 for Mg, 1100–5200?mg?kg^?1 for K, 15,000–68,000?mg?kg^?1 and 36,300–251,000?mg?kg^?1 for Cl. Trace element concentrations in dried sea cucumber samples were found to be 11–100?mg?kg^?1 for Zn, 41–660?mg?kg^?1 for Fe, 3–74?mg?kg^?1 for Cu, 1.1–16?mg?kg^?1 for Mn, 1.4–3.7?mg?kg^?1 for Se, 1.1–9.6?mg?kg^?1 for Cr, and 0.3–5.1?mg?kg^?1 for Ni. All sea cucumber species were rich sources of Na, Cl, Mg, Ca, Fe, Cu, Se and Cr for human consumption. Regarding contaminants, As, Cd and Pb concentrations in dried sea cucumbers were in the ranges of 1.1–6.1, 0.03–0.06 and 0.11–0.69?mg?kg^?1, respectively. Moreover, Hg values of 11 sea cucumbers were below the detection limit (0.01?mg?kg^?1).     

Elements in rice on the Swedish market: Part 2. Chromium,copper, iron,manganese, platinum,rubidium, selenium and zinc

A survey of the levels of some essential and non-essential trace elements in different types of rice available on the Swedish retail market was carried out in 2001–03. The types of rice included long and short grain, brown, white, and parboiled white. The mean levels found were: chromium (Cr)?=?0.008 mg kg^?1, copper (Cu)?=?1.9 mg kg^?1, iron (Fe)?=?4.7 mg kg^?1, manganese (Mn)?=?16 mg kg^?1, platinum (Pt)?<?0.0003 mg kg^?1, rubidium (Rb)?=?3.3 mg kg^?1, selenium (Se) =0.1 mg kg^?1; and zinc (Zn)?=?15 mg kg^?1. Inductively coupled plasma-mass spectrometry (ICP-MS) was used for the determination of Pt, Rb, and Se, after acid digestion. All other elements were determined using atomic absorption spectrometry (AAS) after dry ashing. Intake calculations were performed and it was concluded that rice may contribute considerably to the daily requirements of the essential elements Cu, Fe, Mn, Se, and Zn if rice consumption is high. The levels of some elements, e.g. Fe and Mn, were significantly higher in brown compared with white rice.     

Determination of toxic and essential elements in sunflower honey from Thrace Region,Turkey

The aim of this study was to determine the levels of copper (Cu), manganese (Mn), zinc (Zn), iron (Fe), cadmium (Cd), lead (Pb), chromium (Cr), nickel (Ni) and selenium (Se) in sunflower honeys obtained from Thrace Region of Turkey. Trace and toxic element determination was performed by atomic absorption spectrometry after microwave digestion. The accuracy of the method was checked by the standard reference material, NIST‐SRM 1515 Apple leaves. The maximum contents of trace and toxic elements in honey samples from Kesan (polluted area) were found as 0.46, 0.82, 1.98, 14.0, 9.86 μg kg^?1, 0.48 mg kg^?1, 137, 115 and 290 μg kg^?1 for Cu, Mn, Zn, Fe, Cd, Pb, Cr, Ni and Se, respectively.     

特种水生蔬菜刺苦草根状茎营养成分分析与评价

对刺苦草根状茎的营养成分作了较全面的分析,并与藕、荸荠、水芹菜、茭白等常见水生蔬菜进行了比较。结果显示:刺苦草根状茎的膳食纤维含量十分丰富,蛋白质含量与其它水生蔬菜相比也相对较高。VB1、VB2、VB5的含量是常见水生蔬菜的20～700倍。此外,还含有丰富的K、Na、Ca、Fe、Mg、Cu、Mn、Zn、P、Se、Ni、Cr,尤其P、Na、Mg、Fe、Zn、Se、Cu的含量远远高于常见水生蔬菜。刺苦草根状茎中含有17种氨基酸,包含人体必需氨基酸8种,必需氨基酸含量及氨基酸总量均显著高于常见水生蔬菜。因此,刺苦草根状茎是一种营养丰富的宝贵野生水生蔬菜资源,极具开发利用价值。     

Outdoor grazing of dairy cows on pasture versus indoor feeding on total mixed ration: Effects on gross composition and mineral content of milk during lactation

The influence of feeding system and lactation period on the gross composition, macroelements (Ca, P, Mg, and Na), and trace elements (Zn, Fe, Cu, Mo, Mn, Se, and Co) of bovine milk was investigated. The feeding systems included outdoor grazing on perennial ryegrass pasture (GRO), outdoor grazing on perennial ryegrass and white clover pasture (GRC), and indoors offered total mixed ration (TMR). Sixty spring-calving Holstein Friesian dairy cows were assigned to 3 herds, each consisting of 20 cows, and balanced with respect to parity, calving date, and pre-experimental milk yield and milk solids yield. The herds were allocated to 1 of the 3 feeding systems from February to November. Milk samples were collected on 10 occasions over the period June 17 to November 26, at 2 or 3 weekly intervals, when cows were on average 119 to 281 d in lactation (DIL). The total lactation period was arbitrarily sub-divided into 2 lactation periods based on DIL, namely mid lactation, June 17 to September 9 when cows were 119 to 203 DIL; and late lactation, September 22 to November 26 when cows were 216 to 281 DIL. With the exception of Mg, Na, Fe, Mo, and Co, all other variables were affected by feeding system. The GRO milk had the highest mean concentrations of total solids, total protein, casein, Ca, and P. The TMR milk had the highest concentrations of lactose, Cu, and Se, and lowest level of total protein. The GRC milk had levels of lactose, Zn, and Cu similar to those of GRO milk, and concentrations of TS, Ca, and P similar to those of TMR milk. Lactation period affected all variables, apart from the concentrations of Fe, Cu, Mn, and Se. On average, the proportion (%) of total Ca, P, Zn, Mn, or Se that sedimented with the casein on high-speed ultracentrifugation at 100,000 × g was ≥60%, whereas that of Na, Mg, or Mo was ≤45% total. The results demonstrate how the gross composition and elemental composition of milk can be affected by different feeding systems.     

Nutritional composition of Sonchus species (S asperL,S oleraceusL and S tenerrimusL)

Analyses of the nutritional composition of tender leaves of three species of Sonchus (S. asper L, S oleraceus L and S tenerrimus L) from different locations in the south east of Spain were carried out. The proximate composition, as well as the content of mineral elements (Na, K, Ca, Mg, P, Fe, Cu, Zn and Mn), fatty acids, vitamin C, carotenoids and oxalic acid were determined. The results, which referred to fresh weight, emphasised the low proportion of available carbohydrates. Vitamin C contents were high, and ranged from 457 mg kg⁻¹ (S tenerrimus) to 779 mg kg⁻¹ (S oleraceus). Carotenoids were found in a high proportion (158 mg kg⁻¹) in S oleraceus. Mineral element contents were similar to other green leafy vegetables. Fibre was present in amount above 30 g kg⁻¹ in the three species. Essential fatty acids of the ω3 series were highest in S oleraceus (44·97%). It is believed that these species of Sonchus could be used for nutritional purposes, due to the high concentrations of nutrients that they contain. © 1998 SCI.     

不同矿物元素对干豆腐硬度的影响

为了研究水质对干豆腐硬度的影响,将去离子水中加入不同的矿物元素（Ca、Mg、Zn、Mn、Fe、Cu）用于干豆腐加工,用物性仪测定干豆腐的硬度指标。实验结果显示,Ca2+、Mg2+、Zn2+和Fe3+的添加均对干豆腐的硬度有显著影响,并且随着添加量的增加,干豆腐的硬度均有不同程度的增加。而Cu2+、Mn2+的添加对干豆腐的硬度影响并不显著。分析其原因可能是,不同离子的离子半径及电负性的不同导致其与大豆蛋白质结合方式不同,进而影响干豆腐的硬度指标。      

Dietary manipulation of the yield and composition of milk: Effects of dietary inclusions of barley and oats in untreated or formaldehyde-treated forms on milk fatty acid composition

Eight 1st-lactation cows were given four dietary treatments in a duplicated 4×4 Latin square experiment. Diets consisted of hay and soya bean meal together with barley, formaldehyde-treated barley, oats or formaldehydetreated oats (approximately 34:12:54 on a dry matter basis). Barley diets supplied 211 g fatty acids d^?1, oats diets supplied 537 g d^?1. The fatty acid composition (g kg^?1 total fatty acids) for barley diets was: 300 (16:0); 20 (18:0); 150 (18:1); 470 (18:2); 60 (18:3). Corresponding values for oats diets were 180, 20, 390, 380 and 30 g kg^?1. Formaldehyde treatment of the cereals tended to increase milk yield and reduce milk fat content (P<0·01 for barley) but did not affect milk fatty acid composition. Feeding oats in replacement for barley significantly (P<0·05) increased milk yield and lactose yield and reduced milk fat content (P<0·05 for the untreated cereals) and protein contents (P<0·01) without significant effects on milk fat or protein yields. Oats diets led to significant (P<0·001) reductions in the content of 8:0–16:0 fatty acids in milk fat with associated increases (P<0·001) in the content of 18:0 and 18:1. Changes in milk fat content of 18:2 and 18:3 acids were small. The results show the inclusion of oats in the cow's diet to be a means of reducing the saturated fatty acid content of milk fat thereby improving the nutritional value of milk and milk products and their appeal to the health-conscious consumer.     

Soil and vegetable compositional relationships of eight potentially toxic metals in urban garden fields from northern Nigeria

BACKGROUND: Human exposure to heavy metals is attributed to consumption of vegetables raised in polluted soil environment. We examined the concentrations of As, Cd, Co, Cr, Cu, Ni, Pb and Zn in soils and lettuce (Latuca sativa) and amaranthus (Amaranthus caudatus) in 15 garden fields under long‐term wastewater irrigation. RESULTS: The concentrations of As (0.3–2.1 mg kg^?1), Cd (0.07–0.3 mg kg^?1), Co (4.6–9.1 mg kg^?1) and Cr (21.6–36.2 mg kg^?1) in the gardens were consistent with background concentrations in soils, but Ni (12.6–25.7 mg kg^?1), Cu (12.5–24.6 mg kg^?1), Pb (25.7–71.6 mg kg^?1) and Zn (52.3–158 mg kg^?1) concentrations were double the concentrations normally encountered in arable fields in the region. The concentrations of Cd and As in the vegetables were within safe limits, but Co (0.14–0.67 mg kg^?1 fresh weight (fw)) and Ni (1.0–2.7 mg kg^?1 fw) concentrations in lettuce were relatively high for leaf vegetables. The concentration of Pb (0.65–4.80 mg kg^?1 fw) was above safe limit of 0.3 mg kg^?1 fw, while the concentrations of Cu (1.3–2.7 mg kg^?1 fw and Zn (10.2–23.6 mg kg^?1 fw) were close to the unsafe limits for leaf vegetables. There were no strong linear correlations between soil metal concentrations and bio‐concentrations in the vegetable crops. CONCLUSION: We surmise that leaf vegetables can accumulate metals in their tissues to unsafe levels even when total metal concentrations in these soils are below the allowable concentrations in agricultural soils. Copyright © 2008 Society of Chemical Industry     

Mineral composition of frozen green asparagus

The contents of macroelements (Ca, Mg, Na, K y P) and trace elements (Cu, Fe, Zn and Mn) of frozen green asparagus were determined by atomic absorption spectrometry to investigate the possible changes during 45 and 90 days frozen storage at –18 °C. A significant decrease of mineral concentrations was observed at 45 days of frozen storage. After 90 days, modifications were not observed, except for Cu and P concentrations. The asparagus thickness factor resulted in significant differences in the Cu, Fe, Zn, Ca and K contents. Frozen storage time involved smaller percentages of mineral retention in the <11 mm spear for Ni, Ca, Mg, K and P, and, for the rest of mineral elements, the frozen storage effect was similar for both thicknesses (<11 mm and >14 mm). The highest mineral concentration was found in the apical portion or tip of green asparagus, except for Mn, Cr and K. Mineral retention percentages after frozen storage time were similar in both portions (apical and basal) of the spear.     

Influence of organic selenium supplementation on the accumulation of toxic and essential trace elements involved in the antioxidant system of chicken

The aim of the study was to investigate the interactions between selenium (Se) and various trace elements, both toxic and essential, involved in the antioxidant system. A total of 128?day-old chicks (Gallus gallus, broilers) were used to investigate the effect of Se yeast supplementation on the accumulation of cadmium (Cd), copper (Cu) iron (Fe) and zinc (Zn). There were four replicates of four dietary treatments: T1 (basal diet with no added Se, analyzed to contain 0.21?mg?kg^?1), T2 (T1 with 0.15?mg?kg^?1 Se added), T3 (T1 with 0.3?mg?kg^?1 Se) and T4 (T1 with 3.0?mg?kg^?1 Se). At week 4 and 6, two chickens per replicate pen were sacrificed for whole blood, breast muscle and liver sampling. Samples were analyzed by ICP–MS. Supplementation with Se-yeast, not only increased Se concentration but also reduced Cd concentration in the tissues. Selenium was negatively correlated with Cd and positively correlated with Zn, Cu and Fe. Cadmium was negatively correlated with Zn and Cu. Zinc was positively correlated with Cu. Iron was negatively correlated with Cu and uncorrelated with Zn and Cd. The balance between Se, Cu, Fe and Zn is important for proper antioxidant defense since they are an integral part of various antioxidant enzymes.     

Elemental analysis of nutritional preparations by inductively coupled plasma mass and optical emission spectrometry

This paper reports the development and using of ICP-MS and ICP-OES methods for determination of major, minor and trace elements in multivitamin preparations and dietary supplements and, based on results, their classification using multivariate statistical methods.The method was optimised and evaluated with the use of “in-house” reference material, commercial reference materials and spiked samples. Macroelements (Na, K, Ca, Mg, P), microelements (Cu, Fe, Mn, Zn, Se, Cr), toxic elements (As, Cd, Pb, Ni, V) and a whole series of other elements (e.g. REEs, Ti, Au, Pt, Pd, etc.) were detected with excellent limits of detection as well as other procedure parameters suitable for the purpose of the elemental analysis.As for physiologically significant elements, contents were found as follows (mg kg⁻¹): Ca 560-196,000, Mg 308-70,300, Na 289-74,000, K from undetectable to 28,200, Cu 28-1460, P from undetectable to 217,000, Zn 2.1-25,000, Fe 115-39,400, Mn 28-1860, Cr 0.486-26.6, Mo 0.0418-9.88, and Se 0.395-161. It was found out, if compared with recommended daily intakes, that maximally 50% Ca, 37% Mg, 3% K, 20% P, 14% Na, 100% Cu, 160% Mn, 190% Fe, 120% Zn, 24% Cr, 29% Mo and 79% Se can be obtained from one dose. Extreme samples presenting a possible health risk (Ni content nearly 200 mg kg⁻¹) were indicated. Most of the remaining elements (e.g. REEs) were analysed in order to get reference values for nutritional preparation.     

Mineral content of some Spanish cheese varieties. Differentiation by source of milk and by variety from their content of main and trace elements

The content in nine mineral elements (P. Ca, Na, K, Mg, Zn, Fe, Cu and Mn) was determined in 153 units of cheese belonging to nine Spanish varieties: two unripe cows milk varieties (Cebreiro and Pasiego), three ripened cows milk varieties (Ahumado de Aliva, Leon and Quesucos), three ripened goats milk varieties (Armada-Sobado, Babia-Laciana and Valdeteja), and one blue-veined cows milk variety (Picón). Using a Kruskal-Wallis one-way analysis of variance, only significant differences were observed in P. K, Mg. Zn, Fe and Mn contents associated to animal milk species used in the manufacture. When the two varieties of unripened cheeses were compared, significant differences in all the elements were observed. The same happened when the three varieties of ripened cows milk cheeses were compared. On comparing the three varieties of ripened goats milk cheeses, only significant differences were observed in P, Ca, Na, K, Mg, Zn and Mn contents. Using stepwise discriminant analysis 76–31% of cases were correctly classified when the cheeses were differentiated according to milk species used in their manufacture. When we differentiated the cheeses according to the variety, 91–66% of cases were correctly classified in the unripe cows milk cheeses, 85% of cases were correctly classified in the ripened cows milk cheeses, and 92–59% of cases were correctly classified in the ripened goats milk cheeses.     

Elemental analysis of instant soups and seasoning mixtures by ICP–OES

A method for the determination of Na, K, Ca, Mg, P, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn levels in high saline food products (instant soups and seasoning mixtures) using ICP–OES was developed. The results of the direct determination with multi-elemental water standards were compared with the internal standardisation, the standard addition methods and the allowable limits of the above mentioned elements in food. The method was shown to be sensitive with limits of detection: Na 1.50, K 12, Ca 0.32, Mg 0.13, P 1.1, Cd 0.16, Cr 0.21, Cu 0.32, Fe 0.30, Mn 0.17, Ni 0.42, Pb 2.1 and Zn 0.21 (in mg kg⁻¹). The method exhibited RSD 2–8%.     

Nitrate and nitrite levels in commonly consumed vegetables in Hong Kong

Levels of nitrate and nitrite in 73 different vegetables, a total of 708 individual samples grouped into leafy, legumes, root and tuber, and fruiting vegetables, which are traded mainly in Hong Kong, were measured. Where available, five samples of each vegetable type were purchased from different commercial outlets during the winter of 2008 and summer of 2009. Levels of nitrate and nitrite were determined by ion chromatography and flow injection analysis, respectively. Nitrate and nitrite levels of all samples ranged <4–6300 and <0.8–9.0 mg?kg^?1, respectively. Nitrate concentrations for the different groups, in descending order, were leafy?>?root and tuber?>?fruiting and legume vegetables. More than 80% of vegetables had mean nitrate concentrations less than 2000?mg?kg^?1, but mean nitrate concentrations of three types of leafy vegetables, namely Chinese spinach, Shanghai cabbage and Chinese white cabbage, were >3500?mg?kg^?1. On the other hand, nitrite concentrations were generally low –?<1?mg?kg^?1 on average. Nitrate in vegetables (i.e. Chinese flowering cabbage, Chinese spinach and celery) can be reduced significantly (12–31%) after blanching for 1–3?min, but not after soaking.