Key factors affecting Fe density in Fe-fortified-parboiled rice: Parboiling conditions,storage duration,external Fe-loading rate and genotypic differences

The present study evaluated the key factors affecting the efficiency of iron (Fe) penetration into the endosperm in parboiled rice of different varieties. It also investigated effects of storage time on Fe bio-accessibility, rice colour and Fe retention after rinsing. Rice grains of three varieties were fortified with an increasing range of Fe-fortification rates during the parboiling process, under two typical parboiling conditions, which are ambient soaking temperature for 24 h and 60 °C soaking temperature for 6 h at neutral (6.0–6.5) and acidic pH (3.0–3.5). Soaking of paddy rice, at 60 °C in acidic water for 6 h before steaming, was found to be better for maximising the Fe concentration in white-parboiled rice than the former ambient soaking. Under this parboiling condition, adding 250 mg Fe kg⁻¹ of paddy rice, at soaking, produced the most desirable Fe concentration in white rice, ranging from 17.5 to 25.4 mg kg⁻¹ among the rice varieties tested. The concentrations of Fe in parboiled white rice exhibited an exponential increase with increasing concentrations of Fe in the soaking water in all varieties, which were linearly related to Fe concentration of brown rice (r = 0.96∗∗, p < 0.01). The colour of the parboiled rice fortified with Fe was initially light yellow, with variation among rice varieties, but it did become slightly darker after 16 weeks of storage, probably because of Fe oxidisation. This may be related to decreasing bio-accessibility after 20 weeks of storage. Storage, however, did not affect the total Fe retention after rinsing, though the retention rate was variety-dependent. Information about parboiling will provide the basis for formulating an optimal industry protocol for producing Fe-fortified-parboiled rice, which can be further refined in pilot studies on the industrial scale.     

Isolation and characterization of protein fractions from deoiled rice bran

Rice bran contains underutilised protein materials. Sequential extraction of rice bran protein (RBP) from defatted rice bran was conducted based on the differences in their solubility. Three extraction methods were investigated. Method 1 involved the isoelectric and acetone precipitation using water, 50 g kg⁻¹ NaCl, 0.02 mol L⁻¹ NaOH and 70% ethanol as extracting solvents for albumin (pH 4.1), globulin (pH 4.3), glutelin (pH 4.8) and prolamin, respectively. Method 2 adopted dialysis and sequential extraction was carried out with 20 g kg⁻¹ NaCl, 70% ethanol, 0.1 mol L⁻¹ acetic acid and 0.1 mol L⁻¹ NaOH solution as extracting solvents. Method 3 combined dialysis, isoelectric and acetone precipitation for the extraction. Based on the yields and data obtained from sodium dodecyl sulphate polyacrylamide gel electrophoresis, size-exclusion chromatography and differential scanning calorimetry, method 3 was chosen for the isolation and characterization of RBPs. Rice bran protein fraction (RBPF)—albumin, globulin, glutelin and prolamin were obtained in good yields. Denaturation temperature and enthalpy values of denaturation of RBPF vary. Highest phytate content was found in albumin and lowest in prolamin. The highest antioxidative and hemagglutinating activities were observed in albumin.     

Polycyclic aromatic hydrocarbons (PAHs) in traditional and industrial smoked beef and pork ham from Serbia

Smoked beef and pork ham samples were analysed during process of smoking (after packing and storing) for the presence of the 16 EU priority PAHs via Fast GC/HRMS method. This study showed that there are differences in PAH contents between final smoked beef ham samples from traditional smokehouse (TS) (3.9 μg kg⁻¹) and industrial smokehouse (IS), (1.9 μg kg⁻¹). Also there is a difference in PAH contents in final smoked pork ham samples (4.9 μg kg⁻¹, TS; 4.2 μg kg⁻¹, IS). In beef and pork ham samples from the same smokehouse different PAH contents were observed during smoking. The highest content of examined PAHs in all beef and pork ham samples during smoking showed benzo[c]fluorene (BcL) (beef ham: from 0.3 μg kg⁻¹ to 1.5 μg kg⁻¹; pork ham: from 0.2 μg kg⁻¹ to 2.1 μg kg⁻¹).The maximum level for benzo[a]pyrene (BaP) of 5 μg kg⁻¹ in smoked meat products was not exceeded in any samples. Correlation statistic analysis (P < 0.05) of obtained contents from samples both from TS and IS showed that BaP is a good marker both for 16 EU priority PAHs and 12 IARC probably and possibly carcinogenic PAHs (IS: R _BaP/Σ16PAHs = 0.95, R _BaP/Σ12PAHs = 0.96; TS: R _BaP/Σ16PAHs = 0.71, R _BaP/Σ12PAHs = 0.88).     

Characterisation of Brown and Milled Yellow Rice and Development of an Expanded Snack

Brown rice and yellow milled rice were characterised in relation to milling properties, cooking, processing quality and microbial testing, and utilised to develop an expanded snack. The extrusion process was done in a Mapimpianti single screw cooker-extruder. A flour sample feed rate of 70 g (dry matter) min⁻¹ was maintained by varying the force-feeder speed. A screw speed of 150 rev min⁻¹ and a die with 20 die-nozzle orifices (2 mm in dia) were used. The die zone was heated at 110°C by electrical resistance. Compressed air was circulate around the barrel to maintain precise control of the temperature. The moisture content of the samples was 120, 150 and 180 g kg⁻¹. The grains were classified as long-thin with an average size of 2·13 mm×6·79 mm. The milling yields obtained in the laboratory with paddy rice were 700 g kg⁻¹ brown rice and 600 g kg⁻¹ milled rice. Brown rice and yellow milled rice had similar amylose contents, 225 and 256 g kg⁻¹, respectively. Gel consistency was soft with low gelatinisation temperature (63–68°C) for both samples. Field fungi such as Helminthosporium oryzae and storage fungi as Aspergillus spp were present in paddy, yellow milled and commercial rice. Helminthosporium oryzae was not present in extruded products. The extruded products showed low density and a high degree of expansion, with the optimum degree of expansion obtained in flours processed with moisture at 150 g kg⁻¹ in both milled and brown rice. The highest values for water solubility index were obtained with flours from milled yellow rice and none of the extruded products showed significant differences on water absorption index. Sensory analyses carried out on the snack products showed them to be acceptable, with the bent acceptance for products made from milled yellow rice processed with 150 g kg⁻¹ moisture.     

Evaluation of W-Rh permanent modifier for lead determination in sugar by graphite furnace atomic absorption spectrometry

An alternative procedure that improves the performance of graphite atomizers for the determination of Pb in sugar by electrothermal atomic absorption spectrometry is described. The procedure is based on the injection of 10 μl of an acidified aqueous solution containing 8% w/v sugar and 0.2% v/v HNO₃ into integrated graphite platforms. Either transversely (THGA) as well as longitudinally heated graphite atomizers (LHGA) were evaluated by using conventional co-injection of 0.03% Pd + 0.05% Mg(NO₃)₂ or thermally treated platforms with 250 μg W + 200 μg Rh and co-injection of 5 μg l⁻¹ Rh solution. With W-Rh under the same analytical conditions, the lifetimes of THGA and LHGA reached up to 1110 and 900 firings, respectively. With Pd + Mg the LHGA tube lifetime was limited to approximately 500 firings, but for THGA up to 1020 firings were made with a single tube. Characteristic masses were 11 and 29 pg Pb for LHGA and THGA, respectively. Detection limits (3 s) based on sugar blank solution and on integrated absorbance were 5.0 mg kg⁻¹ with LHGA and 9.3 mg kg⁻¹ Pb for THGA. In general, the coefficients of variation of 20 consecutive measurements of a solution containing 50 μg l⁻¹ Pb were lower than 5%. The obtained detection limits are in consonance with the Codex Alimentarius recommendation for the maximum Pb content in the sugar.     

Iron fortification and parboiled rice quality: appearance,cooking quality and sensory attributes

BACKGROUND: Iron (Fe) fortification of parboiled rice increases both Fe concentration and bioavailability in milled grains (i.e. white rice). The aim of the present study was to evaluate parboiled rice fortified with 250 and 450 mg Fe kg^?1 paddy rice for its pre‐cooking appearance, cooking quality, basic sensory attributes and overall acceptance in comparison with unfortified parboiled rice in Thailand and local parboiled rice in Bangladesh. RESULTS: Fe fortification at 250 mg Fe kg^?1 paddy rice significantly elevated Fe concentration in white rice to as high as 19.1 mg Fe kg^?1 white rice, compared with 6.2 mg Fe kg^?1 white rice for unfortified parboiled rice, without any adverse impact on consumer acceptance based on the current preliminary assessment. The added Fe was well retained in the cooked rice, with significant residual value for human intake. Panellists in Thailand and Bangladesh did not detect significant differences in the acceptability of parboiled rice fortified at 250 mg Fe kg^?1 paddy rice compared with unfortified and local parboiled rice respectively. However, Fe fortification of parboiled rice at the higher level of 450 mg Fe kg^?1 paddy rice significantly intensified the yellow colour of the grain and changed the off‐flavour, chewiness and flakiness of the cooked Fe‐fortified parboiled rice. This resulted in a low acceptability ranking of parboiled rice fortified at 450 mg Fe kg^?1 paddy rice by panellists in both Thailand and Bangladesh. CONCLUSION: Fe fortification of parboiled rice at an appropriate level (e.g. 250 mg Fe kg^?1 paddy rice) is dosage‐effective and acceptable to rice consumers. Consumer acceptability of Fe‐fortified parboiled rice is closely related to pre‐cooking appearance, cooking quality and sensory attributes. Copyright © 2009 Society of Chemical Industry     

Effect of cooking method and rice type on arsenic concentration in cooked rice and the estimation of arsenic dietary intake in a rural village in West Bengal,India

Arsenic (As) contamination of rice plants can result in high total As concentrations (t-As) in cooked rice, especially if As-contaminated water is used for cooking. This study examines two variables: (1) the cooking method (water volume and inclusion of a washing step); and (2) the rice type (atab and boiled). Cooking water and raw atab and boiled rice contained 40 μg As l^?1 and 185 and 315 μg As kg^?1, respectively. In general, all cooking methods increased t-As from the levels in raw rice; however, raw boiled rice decreased its t-As by 12.7% when cooked by the traditional method, but increased by 15.9% or 23.5% when cooked by the intermediate or contemporary methods, respectively. Based on the best possible scenario (the traditional cooking method leading to the lowest level of contamination, and the atab rice type with the lowest As content), t-As daily intake was estimated to be 328 μg, which was twice the tolerable daily intake of 150 μg.     

The effects of freeze, dry, and wet grinding processes on rice flour properties and their energy consumption

This study attempted to replace the wet grinding process of rice with a freeze grinding process. The freeze grinding process involved soaking the rice samples in liquid nitrogen before grinding in a dry grinding machine. Three different types of grinders (hammer mill, roller mill, and pin mill) were used in both the freeze and the dry grinding processes. Wet grinding resulted in significantly (P < 0.05) smaller average particle size and a lower percentage of damaged starch than the alternative methods of grinding. Freeze grinding, especially using the hammer mill significantly reduced both the average particle size and the damaged starch content. Moreover, freeze grinding produced a higher yield after sieving in comparison with dry grinding using an identical grinder. In particular, freeze grinding with the hammer mill gave a significantly higher yield after sieving than dry grinding with the hammer mill. The wet grinding process had the significantly highest specific energy consumption (13,868 kJ/kg) due to the large consumption of electrical energy by the many machines in the process. The energy consumption of freeze grinding was similar to dry grinding. Consequently, the freeze grinding process was a viable alternative to the traditional wet grinding process.     

Development of a single kernel analysis method for detection of 2-acetyl-1-pyrroline in aromatic rice germplasm

Because of the high demand for aromatic rice cultivars that command a premium, it is important to have efficient methods for determining 2-acetyl-1-pyrroline (2-AP), the aromatic compound found in rice, that can be used in breeding efforts and to detect aromatic/non-aromatic blended rice in the marketplace. Solid-phase microextraction (SPME) in conjunction with GC/MS was used to distinguish non-aromatic rice (Oryza sativa, L.) kernels from aromatic rice kernels. In this method, single kernels along with 10 μl of 0.1 ng μl⁻¹ 2,4,6-Trimethylpyridine were placed in sealed vials and heated to 80 °C for 18 min. During the heating stage volatile compounds, which include 2-AP, were adsorbed onto a SPME fiber. Volatiles were desorbed from the fiber and separated using gas chromatography. 2-AP was quantitated by mass spectrometry using the 111, 83 and 68 m/z ions. The method detected 2-AP in milled rice and brown rice; however, its detection in paddy rice was less successful. In a mixture of aromatic and non-aromatic rice, the aromatic rice kernels were differentiated from the non-aromatic rice kernels using the described method. Therefore, this method can be used to identify segregating from non-segregating progeny during early generations in an aromatic rice breeding program when quantities of seed are very limited and can determine if aromatic rice has been adulterated with non-aromatic rice either through inadvertent mixtures, outcrosses or prepared blends.     

Speciation Analysis of Trace Inorganic Arsenic in Dietary Supplements by Slurry Sampling Hydride Generation Atomic Absorption Spectrometry

A new, rapid, and sensitive method was developed for speciation analysis of inorganic arsenic in dietary supplements using slurry sampling hydride generation atomic absorption spectrometry. As(III) content was determined under 1% HCl acidity conditions using both inhibitory effect of 8-hydroxyquinoline (8-HQ) on As(V) and its enhancing effect on As(III). Total inorganic arsenic content was determined under 5% HCl acidity conditions using the enhancing effect of 8-HQ on both As(III) and As(V). The method detection limit (S/N = 3) was 4.0 μg kg^-1 for As(III) and 4.5 μg kg^-1 for total inorganic arsenic. This method was validated using the Chinese standard method (GB/T 5009.11-2003), in good agreement with total inorganic arsenic content in real samples. The developed method was successfully applied to the speciation analysis of inorganic arsenic in dietary supplements with satisfactory results.     

Properties and qualities of rice flours and gluten-free cupcakes made with higher-yield rice varieties in Korea

Korean rice varieties, ‘Druryechanbyeo’ and ‘Boramchanbyeo’, were developed to get higher yields and to be used in rice products. The rice grains were dried and milled into rice flours after first going through the soaking process. The properties and qualities of cupcakes made with dry-milled rice flours were compared with cupcakes made with commercial dry-milled rice flours (CDRF). The newly developed rice flours (NDRF) had higher apparent amylose content, water binding capacity, swelling power, and peak viscosities, but had lower damaged-starch content, gelatinization temperature, and final and setback viscosities than CDRF. The specific gravity of batter, and hardness and springiness of cupcakes were lower in NDRF than in CDRF. The cake textures from ‘Boramchan’ NDRF were more preferable than those from ‘Druyechan’ NDRF. The specific volume and overall quality of cupcake were correlated positively with amylose content and water binding capacity, but negatively with damaged starch of rice flours.     

Total mercury in milled rice and brown rice from China and health risk evaluation

Total mercury (THg) levels in 440 pairs of milled rice samples and brown rice samples from 15 major rice grain-producing provinces of China were measured and the associated health risk via rice consumption for different age categories of Chinese population was also assessed. THg contents were measured by a direct mercury analyser and the limit of detection (LOD) was 1.5 μg kg^?1. The THg levels for milled rice samples and brown rice samples varied from non-detected to 17.8 μg kg^?1 and 1.5 to 25.4 μg kg^?1, respectively, with a mean level of 3.4 μg kg^?1 and 4.9 μg kg^?1, respectively. The THg levels in all milled and brown rice samples were generally low, except three brown rice samples having concentrations above the legally set value for cereals (20 μg kg^?1 Hg). THg intakes for different age categories were estimated according to THg content and corresponding rice consumption and the associated health risk was evaluated by the corresponding provisional tolerable weekly intake (PTWI) for THg (5.0 μg kg^?1 bw week^?1), which was established by the Joint FAO/WHO Expert Committee on Food Additives (JECFA). The 50th percentile of the THg intakes via milled rice and brown rice consumption for different age categories was in the range 0.09–0.19 μg kg^?1 bw week^?1 and 0.14–0.27 μg kg^?1 bw week^?1, respectively, well below the PTWI, suggesting that the associated health risk is relatively low. However, the 99.9th percentile of the THg intakes for 2–4-year-old children amounted up to 20.6% of the PTWI (milled rice) and 29.5% of the PTWI (brown rice), which deserves attention.     

Occurrence of Aflatoxins and Ochratoxin A in Baby Foods in Portugal

Infants have a more restricted diet and they generally consume more food on a body weight basis than adults. Therefore, the significance and potential health risk of any contaminant in foods consumed by infants is increased and diligent attention must be paid to this particular area. The present study aims to determine the occurrence of aflatoxin M₁ (AFM₁), aflatoxin B₁ (AFB₁) and ochratoxin A (OTA) in processed cereal-based foods (flours) and infant formulae (milk powder) available in the Portuguese market, both sold as conventional and organic origin. Mycotoxin determination was carried out using a method previously applied to duplicate diet samples. This method employed chloroform extraction, liquid–liquid extraction, immunoaffinity column (IAC) cleanup and HPLC analysis with fluorescence detection after post-column derivatisation. Quantification limits were 0.014, 0.004 and 0.028 μg kg⁻¹ for AFM₁, AFB₁ and OTA, respectively. These toxins could only be quantified in 12 of 27 analysed samples (15 positive results): two samples with AFM₁, two samples with AFM₁ and OTA, one sample with AFB₁ and OTA and seven samples with OTA. Positive results concerned four for AFM₁ (26%), one for AFB₁ (7%) and ten for OTA (67%). For these samples, contents ranged between 0.017–0.041 μg AFM₁ kg⁻¹, 0.034–0.212 μg OTA kg⁻¹, and one sample had a value of 0.009 μg AFB₁ kg⁻¹. Considering the presented results, we could provisionally conclude that the presence of these mycotoxins in baby foods does not constitute a public health problem. These are the first results concerning the occurrence of mycotoxins in marketed baby foods in Portugal and this is the first study using the HPLC method, proposed for duplicate diets, in baby food sample analysis.     

Analysis of phenolic compounds and isoflavones in soybean seeds (Glycine max (L.) Merill) and sprouts grown under different conditions

Soybeans (Glycine max (L.) Merill) are popularly known as a healthy food in many Asian countries and are mostly consumed as soymilk, tofu, and fermented products such as miso, temph, and sufu. The objective of this study was to determine the variation and composition of phenolic compounds and isoflavone contents in soybean seeds [Glycine max (L.) Merill] and sprouts [Kongnamul] grown under dark conditions (producing yellow soybean sprouts) and in green and yellow boxes (producing green soybean sprouts). In seven soybean cultivars, the total phenolic content ranged from 6.67 μg⁻¹ in Pureunkong to 72.33 μg⁻¹ in Poongsannamulkong. The average total phenolic content in the green soybean sprouts (48.33 μg⁻¹) was higher than in the yellow soybean sprouts (29.75 μg⁻¹). The total phenolic content in the yellow soybean sprouts varied from 9.88 μg⁻¹ to 47.71 μg⁻¹, and the total phenolic content in the green soybean sprouts varied from 29.21 μg⁻¹ to 79.70 μg⁻¹. Only four phenolic compounds, p-hydroxybenzoic acid, salicylic acid, p-coumaric acid, and ferulic acid, were detected in all soybean cultivars. Syringic acid was not detected in yellow soybean sprouts, and myricetin was only detected in yellow soybean sprouts (4.65 μg⁻¹) from the Pureunkong cultivar grown under dark conditions. The total isoflavone content in soybean seeds ranged from 2.1 μg⁻¹ in Sowonkong to 33.0 μg⁻¹ in Pureunkong, and the mean total isoflavones was 10.61 μg⁻¹. Green soybean sprouts had higher average total isoflavones (1389.4 μg⁻¹) than yellow soybean sprouts (559.2 μg⁻¹), and the total isoflavone content was highest in the Pureunkong yellow soybean sprouts (756.3 μg⁻¹) and the Sowonkong green soybean sprouts (2791.6 μg⁻¹). In soybean sprouts, the higher the (malonyl)-daidzin or (malonyl)-genistein content, the higher the total isoflavone level. Our study suggests that producing soybean sprouts enriched in isoflavones under coloured-light sources is feasible.     

The effect of village processing techniques on the content of aflatoxins in corn and peanuts in Zambia

The effect of village processing techniques on the aflatoxin content of corn and peanut products was investigated. In 30 trials, corn kernels were dehulled (bran removal), soaked for 24 h, washed and dried before grinding into flour and boiling in water to a thick consistency (Nshima). Shelled peanuts were either dry-roasted as whole kernels or ground into peanut meal and cooked. Dehulling, following by 24-h soaking (steeping) and subsequent washing significantly (P<0·05) reduced the aflatoxin B₁ content of corn flour from 900 to 150 μg kg⁻¹, and similarly that of aflatoxin G₁ from 929 to 114 μg kg⁻¹. Preparation of Nshima did not result into a substantial reduction in aflatoxin content, neither did extension of the cooking duration of 2 h afford any further decontamination. Whereas boiling peanut meal yielded a moderate reduction in the content of aflatoxins B₁ and G₁, roasting whole peanut kernels greatly reduced (P<0·001) the concentrations of the toxins from that in raw kernels (AFB₁= 8600 μg kg⁻¹ and AFG₁=6200 μg kg⁻¹) to 1300 and 1200 μg kg⁻¹, respectively. These results indicate that specific processing techniques carried out in Zambian villages are effective in reducing aflatoxin carry-over into edible fractions, while others are not. © 1998 SCI.     

A correlation between the level of phenolic compounds and the antioxidant capacity in cooked-with-rice and vegetable soybean (Glycine max L.) varieties

This study was undertaken to determine the content of phenolic compounds contained in embryo, cotyledon and seed coat of nine soybean (Glycine max L.) varieties. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity was also measured to determine the correlation between the level of phenolic compounds and antioxidant capacity. A total of 10 anthocyanin constituents and 21 phenolic compounds was detected and quantified. In all nine varieties, the seed coat and cotyledon had the highest and lowest levels of phenolic compounds and anthocyanins, respectively despite the fact that all of them showed a wide variation in total amounts of phenolic compounds and anthocyanins in seed coat, embryo, and cotyledon. The seed coat tissue, but not other seed parts, showed a strong correlation between the seed coat color and the content of both phenolic compounds and anthocyanins. The brown and black soybean seed coat contained much higher levels of phenolic compounds and anthocyanins in seed coat tissue than the yellow or green coat soybean. Among the individual phenolic compounds, syringic acid (214 μg g⁻¹) and chlorogenic acid (31 μg g⁻¹) were highest in seed coat and embryo, respectively. Myricetin was highest both in whole seed (16.7 μg g⁻¹) and cotyledon (16.0 μg g⁻¹), being equivalent to 20 and 30% of total phenolic compounds, respectively. Among the 10 anthocyanins, cyanidin-3-glucoside was found to accumulate at the highest level in the seed coat (1783 μg g⁻¹), whole seed (106 μg g⁻¹) and embryo (0.35 μg g⁻¹), which correspond to 95, 96, and 40% of the total anthocyanin contents, respectively. The cotyledon accumulated pelargonidin-3-glucoside (0.39 μg g⁻¹) at the highest level that is equivalent to 62% of total anthocyanin contents. DPPH activity was found to have a strong correlation (^***probability < 0.001) with phenolic compounds (0.67^***) and anthocyanins (0.70^***).J. A. Kim, W. S. Jung, and S. C. Chun are equally contributed to this work.     

Incidence of open crack formation in short-grain polished rice during soaking in water at different temperatures

The incidence of open crack formation in short-grain polished rice during soaking in water at different temperatures was investigated. Rice with a moisture content of 10.4% (wet basis) was soaked in distilled water for 90 min at 15 °C, 25 °C or 35 °C, and the rate of open crack formation and the moisture content of the rice during soaking were measured. Results show that the rate of open crack formation increased with decreasing the soaking temperature. A model based on the relationship between the tensile stress calculated from the moisture gradient in a rice grain and the tensile strength calculated from the average moisture content of a rice grain provided a reliable qualitative estimate of the difference in the rate of open crack formation at different temperatures. It can be concluded that water diffusion into rice grains should be accelerated to prevent the formation of open cracks.     

On-line Solid-Phase Extraction Coupled to Liquid Chromatography–Ion Trap Tandem Mass Spectrometry for Determination of Penicillins in Catfish

A highly selective method was developed for the simultaneous determination of eight penicillins in catfish using automated on-line solid-phase extraction coupled to liquid chromatography–tandem mass spectrometry (XLC–MS/MS). The type of cartridge, equilibration sample volume, volume of solvent to carry the sample into the cartridge, and elution times were studied in order to optimize the XLC operating conditions. MS/MS conditions were also adjusted for better peak resolution. The present method was validated in agreement with the criteria of Commission Decision 2002/657/EC, showing a linear range from 2 to 350 μg kg⁻¹ and regression coefficient higher than 0.995 for the studied penicillins. Decision limits, calculated in the case of substances with no permitted limit, were lower than 0.6 μg kg⁻¹, and detection capability values were lower than 2.0 μg kg⁻¹. Samples spiked at 2.0, 10.0, and 50.0 μg kg⁻¹ showed high recovery (72–92%) and precision values lower than 20% except for amoxicillin. The present method was also applied for the analysis of penicillins in 30 catfish samples bought in local markets.     

Selenium uptake and species distribution in selenium-enriched bean (<Emphasis Type="Italic">Phaseolus vulgaris</Emphasis> L.) seeds obtained by two different cultivations

In this work, bean plants were cultivated in two different ways using two modes of selenium supplementation in the form of sodium selenate. Each group consisted of the same four cultivars. Group A plants were grown in soil and twice foliarly sprayed at an interval of 10 days with an aqueous solution of 10 mg Se L⁻¹ at flowering time. Group B plants were hydroponically cultivated after the maternal seeds were soaked in nutrient solution containing the same Se content as used for foliar fertilisation. Bean seeds obtained from group A plants accumulated much more Se (around 2 μg g⁻¹ dry weight) than those seeds obtained from group B plants (around 0.6 μg g⁻¹ dry weight). No differences in Se content within each group were found. After enzyme hydrolysis, 85±7% of soluble selenium was found in group A and 65±2% of soluble Se in group B with respect to the total Se content in seeds. In bean seed supernatants SeMeSeCys, SeMet and two unknown species were found. These four species together represented 79±8 and 53±9% of the Se mass fraction of group A and group B, respectively. No differences in the presence of selenium species were found between the four cultivars and cultivation conditions.     

MSPD Method to Determine Acrylamide in Food

The present work describes the development of an optimized matrix solid-phase dispersion (MSPD) procedure for the analysis of acrylamide in a variety of food matrices, namely, processed cereal products (bread, toasts, breakfast cereals, snacks, cookies, and biscuits), chocolates, and baby foods. Briefly, 1 g of sample was dispersed with 4 g of C₁₈ solid phase, the whole mixture was further packed in an empty SPE column, and acrylamide was extracted with 6 + 6 ml of water with a soak step of 5 min each. The aqueous extract was then subject to a bromination procedure and acrylamide quantified by gas chromatography–mass spectrometry (GC-MS) in SIM mode. Full validation of the method was conducted in samples representatives of each one of the food groups analyzed including a comparison of the results obtained by using the reported method with those furnished by a previously developed analytical procedure based on a liquid extraction approach. The MSPD-GC/MS method presented a limit of detection of 5.2 μg kg⁻¹ and a limit of quantification of 15.7 μg kg⁻¹, and precisions were in the range of 1–7% in all of the food matrices analyzed. Furthermore, the bias of the method was tested with a certified toasted bread sample.