Folate content in foods commonly consumed in Egypt

The folate content in some Egyptian foods was determined using RP-HPLC-FL. Trienzyme treatment was used for legumes, dienzyme treatment for cereals and starchy vegetables, and monoenzyme treatment for vegetables and fruits. The highest folate content (633 μg/100 g) was found in dried Jew’s mellow due to low water content, followed by legumes (e.g. 150 μg/100 g for chick peas) and leafy vegetables (100 μg/100 g). For other foods, folate content ranged from 10–90 μg/100 g. In all foods, the predominant folate form was 5-CH₃–H₄folate, except for dried Jew’s mellow, which contained more than 80% 10-HCO–PteGlu. Using folate data from our own analyses and food tables and food consumption data, the dietary folate intake per capita in Egypt was estimated. However, representative and validated food composition data for folate in Egyptian foods are needed for estimating and evaluating the adequacy of the population’s folate intake.     

Chromium and manganese levels in convenience and fast foods: In vitro study of the dialyzable fraction

Chromium and manganese presence was determined in a total of 170 samples of convenience and fast foods widely consumed in Spain. Electrothermal atomic absorption spectrometry was used as analytical technique. Reliability of the procedure was checked. Cr levels ranged from 0.01 to 1.10 μg/g (fresh weight of edible portion). The most elevated levels were found in beef and pork based-food, food with a greater content of spices and aromatic herbs, whole cereals, dry fruits and cheese. Mn levels ranged from 0.15 to 2.90 μg/g (fresh weight of edible portion). The most elevated levels of Mn were found in chicken and pork-based foods and sauces. Mean Cr and Mn dialyzable fraction estimated by in vitro assays ranged from 0.38% to 1.05% and from 7.75% to 15.60%, respectively. These findings revealed that certain convenience and fast foods contribute a considerable fraction of Cr and Mn dietary intake.     

Evaluation of trace element contents in canned foods marketed from Turkey

Trace element contents of 10 canned foods (mushroom, corn, pea, mixed vegetable, tomato, red mullet, stuffed grape leaves, pickle, bean, delicatessen) from Turkish markets were determined by flame and graphite furnace atomic absorption spectrometry after microwave digestion. The accuracy of the method was determined by use of a standard reference material (NIST SRM 1573a Tomato Leaves). The contents of investigated trace elements in canned foods were found to be in the range of 2.85–7.77 μg/g for copper, 8.46–21.9 μg/g for zinc, 6.46–18.6 μg/g for manganese, 27.5–79.6 μg/g for iron, 0.05–0.35 μg/g for selenium, 0.93–3.17 μg/g for aluminium, 0.19–0.52 μg/g for chromium, 0.18–0.75 μg/g for nickel, and 0.20–1.10 μg/g for cobalt. The results found were compared with those reported by scientists from various countries.     

Chromium determination in food by slurry sampling graphite furnace atomic absorption spectrometry using classical and permanent modifiers

A simple method, using permanent modifiers, has been developed for chromium (Cr) determination in food of plant origin by the slurry sampling graphite furnace atomic absorption spectrometry. In particular comparison of the action of Mg(NO₃)₂, iridium (Ir)/niobium (Nb) and iridium (Ir)/tungsten (W) was examined. Finally, for chromium determination in food, the mixture of 2 μg of Ir with 10 μg of Nb was used as permanent modifier. The analytical procedure was optimised carefully on the basis of the data from pyrolysis and atomisation temperature curves studies. The results obtained for four certified reference materials using external calibration with aqueous standards were in good agreement with the certified values. The precision and accuracy of Cr determination by the described method were also acceptable: the RSD were lower than 10% and recoveries for CRMs were in the range of 95-103%. The characteristic mass for chromium was determined to be 3.9 pg and the detection limit for the optimised procedure at the 0.75% (w/v) slurry concentration - 86.6 ng g⁻¹.     

Fumonisin level in corn-based food and feed from Linxian County,a high-risk area for esophageal cancer in china

The level of mycotoxin fumonisins in corn-based food and feed collected from Linxian County, a high-risk area for esophageal cancer in China, has been analyzed using high-performance liquid chromatographic coupled with evaporative laser scattering detector (HPLC-ELSD). A total of 104 corn kernel samples were obtained from local households, granaries, wholesale markets (central markets), and retail markets (stores and supermarkets). Fumonisin B₁ (FB₁) was detected in the samples from households, granaries, central markets, and stores, with a positive rate of 61.5%, 50%, 33.3%, and 17%, respectively. No fumonisin was detected in samples from the supermarket. The highest FB₁ levels (0.30–3.20 μg/g; mean, 1.42 μg/g) were found in samples from the granary, followed by household (0.25–1.80 μg/g; mean, 0.73 μg/g), central market (0.25–1.10 μg/g; mean, 0.51 μg/g), and store (0.22–0.34 μg/g; mean, 0.28 μg/g). Among the 80 corn kernel samples collected from local households, 18 of 24 (75.0%) moldy samples contained high levels of FB₁ (0.28–3.30 μg/g; mean, 1.58 μg/g), and 20 of 56 (35.7%) apparently healthy samples contained low levels of FB₁ (0.21–0.82 μg/g; mean, 0.46 μg/g). As the central market plays an important role in trade of corn-based food and feed in China, a total of 115 corn-based food and feed samples were collected from the local central market. The highest FB₁ levels (0.30–3.13 μg/g; mean, 1.50 μg/g) were found in feed, followed by unprocessed food (0.31–0.63 μg/g; mean, 0.47 μg/g) and processed food (0.21–0.28 μg/g; mean, 0.25 μg/g). The positive incidence of FB₁ in feed, unprocessed, and processed food were 53.6%, 33.3% and 17.9%, respectively. In conclusion, the results showed that corn-based food and feed from Linxian County contained low level of FB₁ (<2 μg/g) in general, but efforts should be made to control the fumonisin contamination in corn kernels stored in granaries and households.     

Trace metal content in nine species of fish from the Black and Aegean Seas,Turkey

Trace metal content of nine fish species harvested from the Black and Aegean Seas were determined by microwave digestion and atomic absorption spectroscopy (MD–AAS). Verification of the MD–AAS method was demonstrated by analysis of standard reference material (NRCC-DORM-2 dogfish muscle). Trace metal content in fish samples were 0.73–1.83 μg/g for copper, 0.45–0.90 μg/g for cadmium, 0.33–0.93 μg/g for lead, 35.4–106 μg/g for zinc, 1.28–7.40 μg/g for manganese, 68.6–163 μg/g for iron, 0.95–1.98 μg/g for chromium, and 1.92–5.68 μg/g for nickel. The levels of lead and cadmium in fish samples were higher than the recommended legal limits for human consumption.     

Phytoestrogen content of fruits and vegetables commonly consumed in the UK based on LC–MS and C-labelled standards

Phytoestrogens are a group of non-steroidal secondary plant metabolites with structural and functional similarity to 17β-oestradiol. Urinary and plasma phytoestrogens have been used as biomarkers for dietary intake, however, this is often not possible in large epidemiological studies or to assess general exposure in free-living individuals. Accurate information about dietary phytoestrogens is therefore important but there is very limited data concerning food contents. In this study, we analysed the phytoestrogen (isoflavone, lignan and coumestrol) content in more than 240 different foods based on fresh and processed fruits and vegetables using a newly developed sensitive method based on LC–MS incorporating ¹³C₃-labelled standards. Phytoestrogens were detected in all foods analysed with a median content of 20 μg/100 g wet weight (isoflavones: 2 μg/100 g; lignans 12 μg/100 g). Most foods contained less than 100 μg/100 g, however, 5% of foods analysed contained more than 400 μg/100 g, in particular soya-based foods and other legumes. The results published here will contribute to databases of dietary phytoestrogen content and allow the more accurate determination of phytoestrogen exposure in free-living individuals.     

Determination of vitamin K1 content in olive oil,chard and human plasma by RP-HPLC method with UV–Vis detection

The contents of phylloquinone (Vitamin K₁) were investigated in olive oil, chard and human plasma based on a reversed phase high performance liquid chromatographic method with acetonitrile/dichloromethane/methanol (60:20:20, v/v/v) as eluent in a C₁₈ μ-Bondapak column (10 μm, 300 × 3.9 mm) at 20 °C. Detection was by UV–Vis detector at 248 nm. In olive oil, the mean content of phylloquinone ranged from 12.7 to 18.9 μg/100 g, in chard ranged from 65.5 to 77.5 μg/100 g. In human plasma, phylloquinone content varied between 0.22 and 0.56 ng/ml.     

Effect of food matrix on amandin, almond (Prunus dulcis L.) major protein, immunorecognition and recovery

Amandin, the primary storage protein in almonds, contains key polypeptides recognized by almond-allergic patients. A variety of food matrices representing diverse categories of foods were analyzed to assess the effect of food matrix on amandin recognition and recovery using rabbit polyclonal antibody based immunoassays. Food matrices from dairy, nuts, and vegetables typically resulted in over-estimation of amandin. Some foods representing legumes and cereals resulted in over-estimation while others in under-estimation of amandin. The amandin recovery range was 116-198 μg/100μg (dairy) 110-292 μg/100μg (tree nuts), 43-304 μg/100μg (legumes), 106-183 μg/100μg (most cereals- with the exception of barley, whole-wheat flour, wild rice and raisin bran whole mix). Amandin recovery from spices was typically low (2-85 μg/100μg) with a few exceptions where higher recoveries were observed (121-334 μg/100μg). Salt (black and white), tea, confectionery (sugar, cocoa, dark chocolate), and fruits (1-83 μg/100μg) generally resulted in lower recoveries. Tested food matrices did not adversely affect amandin immunorecognition in Western blots. The pH and the extraction buffer type affected amandin recovery. The results suggest that food matrix effects as well as extraction conditions need to be carefully evaluated when developing immunoassays for amandin detection and quantification.     

Beta-carotene,lycopene, and alpha-tocopherol contents of selected Thai fruits

A total of 37 varieties of fresh fruits obtained from six representative markets in Bangkok, Thailand, were determined for their beta-carotene, lycopene, and alpha-tocopherol contents using high performance liquid chromatography. Beta-carotene content ranged from undetectable up to 616 μg/100 g of edible portion, lycopene content from undetectable up to 6693 μg/100 g and vitamin E content from not undetectable up to 1.43 mg/100 g. Red watermelon, Citruluss vulgalis (“jin-trarah” variety) was the richest source of dietary beta-carotene (1040 μg/serving) and lycopene (11,378 μg/serving), whilst the highest alpha-tocopherol content was found in unripe mango, Mangifera indica (“keosawoei” variety) with approximately 0.90 mg/75 g of edible portion, providing 9% of the Thai recommended daily intake of vitamin E.     

Effect of refining processes on antioxidant capacity,total contents of phenolics and carotenoids in palm oils

Antioxidant capacity (AC), total phenolic content (TPC) and total carotenoid content (TCC) in palm oils at various stages of the refining process from two technological modes were determined. The obtained mean FRAP and DPPH values for the methanolic extracts of palm oils from mode 1 (19.5–102.8 μmol TE/100 g and 18.8–103.0 μmol TE/100 g) were lower than for oils from mode 2 (25.6–134.8 μmol TE/100 g and 25.4–135.4 μmol TE/100 g). The total phenolics (4.1–12.4 mg GA/100 g) and carotenoids (0.18–45.8 mg/100 g) in the studied oils were correlated with their antioxidant capacities determined by FRAP and DPPH methods (r = 0.6623–0.9878). During the refining process, for both technological modes resulted in a loss of AC by 80%, TPC by 26–55% and TCC by 99%. The bleaching step caused the highest losses of AC as determined by FRAP 41% and 46%, DPPH by 43% and 48%, while TPC loss was 45% and 23% and loss of carotenoids was 49% and 56%, in mode 1 and mode 2, respectively.     

Mercury and its bioconcentration factors in Brown Birch Scaber Stalk (Leccinum scabrum) from various sites in Poland

The total mercury contents were determined in the carpophores of Brown Birch Scaber Stalk (Leccinum scabrum) and topsoil (0–10 cm) collected from 12 spatially distant sites across Poland. Mercury was measured by cold-vapour atomic absorption spectroscopy (CV-AAS) after nitric acid (mushrooms) or aqua regia (soil) digestion of the samples. The caps, depending on the site, had total mercury concentrations from 0.38 ± 0.23 to 1.2 ± 0.4 μg/g dm (median 0.36–1.2 μg/g dm), and stalks from 0.17 ± 0.08 to 0.72 ± 0.20 μg/g dm (median 0.17–0.72 μg/g dm). Overall-mean mercury contents for 240 caps and stalks were 0.63 ± 0.38 (0.072–2.0 μg/g dm) and 0.32 ± 0.20 (0.028–1.2 μg/g dm), respectively. The total mercury content in top soil layer (0–10 cm) at 12 sites, after hot aqua regia extraction, averaged 0.026 ± 0.010–0.066 ± 0.018 μg/g dm. The BCF values of total mercury in caps of Brown Birch Scaber Stalk from the particular sites ranged from 14 ± 5 to 20 ± 4 (total mean was 16 ± 5, and median 18), in stalks from 6.0 ± 4.0 to 11 ± 1 (total mean was 8.3 ± 3.1, and median 8.1). In human feeding, wild mushrooms are usually only a small part of the total diet, so consumption of Brown Birch Scaber Stalk collected from the background sites in Poland, or elsewhere in Europe, as regards mercury content, could be considered safe.     

Determination of trace metals in canned fish marketed in Turkey

The levels of trace metals of canned fish samples collected from markets in Turkey were determined by flame and graphite furnace atomic absorption spectrometry after microwave digestion. The accuracy of the method was corrected by standard reference material (NRCC-DORM-2 Dogfish Muscle). The contents of investigated trace metals in canned fish samples were found to be in the range 1.10–2.50 μg/g for copper, 7.57–34.4 μg/g for zinc, 0.90–2.50 μg/g for manganese, 10.2–30.3 μg/g for iron, 0.96–3.64 μg/g for selenium, 0.45–1.50 μg/g for aluminium, 0.97–1.70 μg/g for chromium, 0.42–0.85 μg/g for nickel, 0.09–0.40 μg/g for lead and 0.06–0.25 μg/g for cadmium. The results were compared with the literature values.     

Development of enzyme-linked immunosorbent assay (ELISA) for the detection of neomycin residues in pig muscle,chicken muscle,egg, fish,milk and kidney

A colorimetric competitive direct enzyme-linked immunosorbent assay (ELISA) method was developed using polyclonal antibody to determine neomycin residues in food of animal origin. No cross-reactivity of the antibody was observed with other aminoglycosides. The limit of detection of the method was 0.1 μg/kg. A simple and efficient sample extraction method was established with recoveries of neomycin ranged from 75% to 105%. The detection limits were 5 μg/kg(l) in pig muscle, chicken muscle, fish and milk, 10 μg/kg in kidney and 20 μg/kg in egg, respectively. Chemiluminescence assay was developed for detecting neomycin residues in pig muscle and chicken muscle. The limit of detection of the method was 0.015 μg/kg, and the detection limits were 1.5 μg/kg in pig muscle and 6 μg/kg in chicken muscle. The ELISA tests were validated by HPLC, and the results showed a good correlation (r²) which was greater than 0.9.     

Infusion and decoction of wild German chamomile: Bioactivity and characterization of organic acids and phenolic compounds

Natural products represent a rich source of biologically active compounds and are an example of molecular diversity, with recognised potential in drug discovery. Herein, the methanol extract of Matricaria recutita L. (German chamomile) and its decoction and infusion (the most consumed preparations of this herb) were submitted to an analysis of phytochemicals and bioactivity evaluation. The antioxidant activity was determined by free radicals scavenging activity, reducing power and inhibition of lipid peroxidation; the antitumour potential was tested in human tumour cell lines (breast, lung, colon, cervical and hepatocellular carcinomas), and the hepatotoxicity was evaluated using a porcine liver primary cell culture (non-tumour cells). All the samples revealed antioxidant properties. The decoction exhibited no antitumour activity (GI₅₀ > 400 μg/mL) which could indicate that this bioactivity might be related to compounds (including phenolic compounds) that were not extracted or that were affected by the decoction procedure. Both plant methanol extract and infusion showed inhibitory activity to the growth of HCT-15 (GI₅₀ 250.24 and 298.23 μg/mL, respectively) and HeLa (GI₅₀ 259.36 and 277.67 μg/mL, respectively) cell lines, without hepatotoxicity (GI₅₀ > 400 μg/mL). Infusion and decoction gave higher contents of organic acids (24.42 and 23.35 g/100 g dw). Otherwise, the plant methanol extract contained the highest amounts of both phenolic acids (3.99 g/100 g dw) and flavonoids (2.59 g/100 g dw). The major compound found in all the preparations was luteolin O-acylhexoside. Overall, German chamomile contains important phytochemicals with bioactive properties (mainly antitumour potential selective to colon and cervical carcinoma cell lines) to be explored in the pharmaceutical, food and cosmetics industries.     

Nutritive and non-nutritive attributes of washed-up seaweeds from the coast of Ceará, Brazil

This study assesses the nutritive and non-nutritive attributes of washed-up seaweeds from the Brazilian coast. It covers a broad diversity of species (24 red, nine green and four brown) with reasonable levels of proteins (10–14.8%), high ash contents (13–25%), low lipids (below 1%) and high carbohydrate contents (60%). Toxic and/or antinutritional factors were detected, such as low levels of lectins (32 and 64 HU/g of meal for chicken and rabbit trypsin-treated erythrocytes, respectively), tannins (59 mg/100 g), phytic acid (0.45%), high levels of trypsin inhibitors (99.0% inhibition) and -amylase inhibitors (70.5%). The 0/80% fraction showed moderate toxicity to mice (LD₅₀ of 63.8 mg kg⁻¹). The presence of heavy metals such as cadmium (0.29 mg/100 g), chromium (0.23 mg/100 g), nickel (0.26 mg/100 g) and vanadium (3.56 mg/100 g) was also detected. Despite moderate toxicity and antinutritional limitations, washed-up seaweeds represent a potential food alternative for humans after appropriate processing and environmental remediation to guarantee food safety.     

Rapid determination of cholesterol in milk containing emulsified foods

In this study, a rapid and easy sample preparation method that involved no-heating saponification and dSPE (dispersive solid phase extraction) clean-up was developed to determine the level of cholesterol in milk containing emulsified foods (infant formula, baby food, cheese). The developed method utilised high performance liquid chromatography with an ultraviolet detector (HPLC-UVD) as a separation instrument. The optimum extraction conditions were determined as 10 mL isopropyl alcohol with 8.0 g (NH₄)₂SO₄ per 1 g sample, and saponification was achieved using 25 mg KOH, 1.6 g NaCl and 100 mg of a silica based NH₂. Cholesterol levels determined using CRMs (NIST SRM 1849 and 1544) were in the range of the certificated value and the recovery test using spiked materials ranged from 94.34% to 102.34% with a RSD of 0.63–4.10%. This method enables the accurate determination of cholesterol with reduced sample preparation time.     

Determination of Allura red in food samples after cloud point extraction using mixed micelles

A cloud point extraction process using mixed micelles of CTAB, Triton X-114 and Triton X-100 for preconcentration and spectrophotometric determination of trace amounts of Allura red in food samples was developed. The effect of different parameters such as concentration of surfactants, electrolyte concentration, temperature and pH on the cloud point extraction of Allura red was studied in detail and a set of optimum conditions were established. A linear calibration curve in the range of 20–1400 μg/L of Allura red was obtained. Detection limit based on 3S_b was 7.8 μg/L and the relative standard deviation for 75 μg/L of Allura red was 3.87 (n = 10). The method was applied to the determination of Allura red in food samples such as candy, soft drink and jellies.     

The influence of latitude on the concentration of vitamin D3 and 25-hydroxy-vitamin D3 in Australian red meat

There is little information on the vitamin D content of Australian red meat or on the possible influence of latitude on this content. To determine the content of vitamin D₃ and 25-hydroxy-vitamin D₃ (25OHD₃), lamb and beef were analysed from 34° S with LC–IT-MS. To investigate the possible influence of latitude on vitamin D in meat, the lean meat and fat from five cuts of beef were analysed from 17° S and 41° S. Lamb contained 0.10 μg vitamin D₃/100 g and 0.20 μg 25OHD₃/100 g lean meat, while beef contained 0.12 μg vitamin D₃ and 0.27 μg 25OHD₃/100 g (lean meat). Latitude had no effect on the vitamin D₃ (P = 0.21) or 25OHD₃ (P = 0.29) content of lean beef, but fat from cattle in the 17° S latitude group contained significantly higher (P < 0.01) concentrations of vitamin D₃ than fat from the 41° S group of cattle.     

Folate contents of some selected Fijian foods using tri-enzyme extraction method

Folic acid and total folate contents of 18 common foods in the Fijian diet were assayed. Foods were purchased from the central and eastern parts of Viti Levu in Fiji. Tri-enzyme treatment was performed to release bound folates using protease and α-amylase, with chicken pancreas as the conjugase. The highest total folate content was recorded for egg yolk (Gallus domesticus) at 256 μg/100 g, followed by long beans (Vigna sesquipedalis) which contained 130 μg/100 g of total folate (fresh weight basis). The local leafy vegetable called Bele (Abelmoschus manihot) and the Drumstick leaves (Moringa oleifera) available in Fiji also had high total folate contents, above 100 μg/100 g (fresh weight basis). For the 18 foods studied, the content of folic acid ranged from 3 to 189 μg/100 g and the total folate content was in the range of 3–256 μg/100 g, indicating a very wide range of folate content in the foods studied.