Development of a fast analytical method for the determination of sudan dyes in chili- and curry-containing foodstuffs by high-performance liquid chromatography-photodiode array detection

A simple and fast analytical method for the determination of sudans I, II, III, and IV in chili- and curry-containing foodstuffs is described. These dyes are extracted from the samples with acetonitrile and analyzed by high-performance liquid chromatography coupled to a photodiode array detector. The chromatographic separation is carried out on a reverse phase C18 column with an isocratic mode using a mixture of acetonitrile and water. An "in-house" validation was achieved in chili- and curry-based sauces and powdered spices. Depending on the dye, limits of detection range from 0.2 to 0.5 mg/kg in sauces and from 1.5 to 2 mg/kg in spices. Limits of quantification are between 0.4 and 1 mg/kg in sauces and between 3 and 4 mg/kg in spices. Validation data show a good repeatability and within-lab reproducibility with relative standard deviations < 15%. The overall recoveries are in the range of 51-86% in sauces and in the range of 89-100% in powdered spices depending on the dye involved. Calibration curves are linear in the 0-5 mg/kg range for sauces and in the 0-20 mg/kg range for spices. The proposed method is specific and selective, allowing the analysis of over 20 samples per working day.     

Characterization of a calcium-soluble protein fraction from yellow mustard (Sinapis alba) seed meal with potential application as an additive to calcium-rich drinks

A calcium-soluble protein isolate (CSPI) was prepared from the supernatant obtained after addition of 0.75 M calcium chloride to a pH 5.0 aqueous extract of yellow mustard (Sinapis alba) seed meal. Total amino acid analysis showed that the CSPI has significantly higher (p < 0.05) contents of glutamic acid + glutamine, cysteine, and proline when compared to the precipitated, calcium-insoluble proteins. Peptide mass fingerprinting of tryptic peptides of the major polypeptides by mass spectrometry indicated that the CSPI is composed mainly of cruciferin proteins with a contribution from napins (the major allergenic proteins of S. alba). The S. alba CSPI had significantly higher (p < 0.05) protein solubility and emulsion formation ability in the presence of 0.75 M calcium chloride when compared to similar isolates prepared from Brassica juncea (brown mustard) and soybean seed meals. We suggest that the S. alba CSPI could be used to prepare calcium-fortified high protein liquid products. However, the presence of allergenic proteins in this extract may limit its widespread food use.     

Use of anion-exchange membrane extraction for the high-performance liquid chromatographic analysis of mustard seed glucosinolates

A new one-step extraction using anion-exchange membranes for the HPLC determination of glucosinolates in mustard seeds is reported. The exchange of glucosinolates on the membranes was studied using sinigrin in solutions and sinigrin added as an internal standard to seeds of yellow mustard. By varying time of extraction, membrane size, and sample size, the optimal conditions for maximum glucosinolate recovery were determined and the following procedure was adopted: 0.2 g of ground mustard seeds are heated in 20 mL of boiling water for 5 min. After cooling, samples are transferred to plastic centrifuge tubes, 9-cm(2) membranes are added, and suspensions are shaken on a mechanical shaker for 2.5 h. Glucosinolates are then eluted from the membranes with 25 mL of 1 N KCl by shaking again for 2.5 h. Using this procedure, the sinigrin extraction from solutions and from mustard seeds was linear with 80% recovery. Seeds of yellow, brown, oriental, and Indian mustard were analyzed by this procedure; excellent reproducibility, with coefficients of variation in the range 1.0-4.3% were obtained. This method offers a simple and inexpensive alternative to complicated and tedious procedures for glucosinolate isolation/purification required for chromatographic determinations.     

Genetic Diversity of Traditional Chinese Mustard Crops Brassica juncea as Revealed by Phenotypic differences and RAPD Markers

This investigation was aimed at exploring the genetic diversity among nine typical accessions of Chinese mustard crops using random amplified polymorphic DNA (RAPD) markers and morphological comparison. Totally, 111 reproducible DNA bands were generated by 16 arbitrary primers, of which 91 bands were proved to be polymorphic. Based on pair-wise comparisons of the amplified bands, genetic similarities were obtained using Nei & Li's similarity coefficients and a dendrogram reflecting their relationships was made using the unweighted pair–group method with arithmetic averages (UPGMA). The result of cluster analysis indicated that the nine accessions were capable of being classified into two primary groups, one including accession 2 with expanded root (root mustard), accession 3 with entirely expanded whole stem (long-stem mustard), accession 6 with edible leaves (leaf mustard), accession 8 with edible seed stalk (seed stalk mustard) and another one including accession 4 with expanded basal stem (short-stem mustard), accession 5 with bulgy petiole (leafy bulgy mustard), and accession 9 with mustard-rich seed (seed mustard). Besides, accession 1 with expanded root (root mustard) and accession 7 with edible leaves and seed stalk (seed stalk mustard) were independent of other accessions in the dendrogram. Additionally, by cluster analysis based on highly reproducible RAPD markers, the accessions with similar edible parts of leaves or roots were not actually in the same phylogenetic groups. This implied that they were probably derived from different geographical origins with dissimilar genetic background and possessed higher genetic diversification. Furthermore, the results indicated that the traditional method for classifying Chinese mustard crops was not much reliable as it was largely dependent on phenotypic behaviors. Meanwhile, the phenotypic differences among individuals did not necessarily mean they must have sharp difference in genetic background as they met in the same group. Undoubtedly, these results aforementioned make this crop quite interesting to researchers for further investigating the molecular evolution of this special AABB group.     

Multiplex, quantitative, ligation-dependent probe amplification for determination of allergens in food

Legislation requires labeling of foods containing allergenic ingredients. Here, we present a robust 10-plex quantitative and sensitive ligation-dependent probe amplification method, the allergen-multiplex ligation-dependent probe amplification (MLPA) method, for specific detection of eight allergens: sesame, soy, hazelnut, peanut, lupine, gluten, mustard, and celery. Ligated probes were amplified by polymerase chain reaction (PCR), and amplicons were detected using capillary electrophoresis. Quantitative results were obtained by comparing signals with an internal positive control. The limit of detection varied from approximately 5 to 400 gene copies, depending on the allergen. The method was tested using different foods spiked with mustard, celery, soy, or lupine flour in the 1-0.001% range. Depending on the allergen, sensitivities were similar or better than those obtained with qPCR. The allergen-MLPA method is modular and can be adapted by adding probe pairs for other allergens. The DNA-based allergen-MLPA method will constitute a complementary method to the traditional protein-based methods.     

A New Simple Method for the Evaluation of Mineral Elements in Different Oilseeds

A method for the analysis of seven mineral contents—that is, potassium (K), calcium (Ca), phosphorus (P), iron (Fe), manganese (Mn), zinc (Zn), and copper (Cu)—was investigated in some oilseeds like flax, sesame, pumpkin, quinoa, and yellow mustard. X-ray Spectral Analysis method with Spectrometer EDX-900HS was used for the analytical concentrations of the macro and micro elements of the oilseeds. A relatively high level of Zn content was found in sesame and pumpkin seeds, while the highest level of Fe content was found in mustard seeds. Regarding the macro elements (K, Ca, and P) content, the highest levels of concentration were found in flax and mustard seeds. The highest values of Cu were obtained in sesame seeds while those of Mn were in pumpkin and brown flax seeds. The results showed that the method is a reliable and simple analytical procedure to characterize mineral elements in oilseeds with a very high analytical performance.     

Characteristics of salt-fermented sauces from shrimp processing byproducts

A salt-fermented sauce from shrimp processing byproducts (heads, shells, and tails) was prepared and characterized. Three types of sauces were prepared; sauce C, with 30 g of salt/100 g of byproduct (high salt); sauce E, with 30 g of salt and 0.2 g of sodium erythorbate (high salt); and sauce L, with 20 g of salt, 0.2 g of sodium erythorbate, 6 g of sorbitol, 0.5 mL of lactic acid, and 5 mL of ethanol (low salt). Sauces C and E showed higher exopeptidase activities than sauce L, whereas sauce L showed the highest endopeptidase activity. After 3 months of fermentation, the amino N content of sauce increased from 150-200 to 500-600 mg/100 g and the nonprotein nitrogen content increased from 300 to 950-1050 mg/100 g. Volatile basic nitrogen content increased significantly from 18 to 60 mg/100 g. The total carotenoids retained in sauces C, E, and L were 26.3, 76.2, and 73%, respectively, thus indicating that the addition of sodium erythorbate to sauces E and L retarded oxidation. Water activities of sauces C, E, and L were 0.753, 0.751, and 0.773, respectively. According to the omission test, the taste of sauces was influenced by the content of free amino acids, mainly glutamic acid and aspartic acid. All three sauces examined showed a 35% higher total amino acid content than commercial salt-fermented shrimp sauces. Therefore, shrimp processing byproducts may lend themselves to the preparation of high-quality salt-fermented sauces.     

Determination and quantification of γ-glutamyl-valyl-glycine in commercial fish sauces

It was recently reported that kokumi substances such as glutathione are perceived through the calcium-sensing receptor (CaSR). In addition, screening by the CaSR assay and sensory evaluation revealed that γ-glutamyl-valyl-glycine (γ-Glu-Val-Gly) was a potent kokumi peptide. In this study, the quantities of γ-Glu-Val-Gly in various commercial fish sauces originating from Vietnam (Nuoc Mum), Thailand (Nampra), China (Yu-lu), Korea, Japan (Shottsuru and Ikanago-shoyu), and Italy (Garum) were investigated using a LC/MS/MS method followed by derivatization with 6-aminoquinoyl-N-hydroxysuccinimidyl-carbamate (AQC). The analyses revealed γ-Glu-Val-Gly at concentrations ranging from 0.04 to 1.26 mg/dL, indicating that γ-Glu-Val-Gly is widely distributed among various commercial fish sauces.     

Comparison of Phosphorus Determination Methods by Ion Chromatography and Molybdenum Blue Methods

The suppressed ion chromatography (IC) and molybdenum blue methods were used to comparatively evaluate phosphorus (P) concentrations. Most of the P was more resistant to hydrolysis in ion chromatography as compared to the molybdenum blue method. However, P analysis by IC is more liable to be interfered than the molybdenum blue method because of the presence of high bivalent and trivalent metal ions. Polyvalent metal ions interfere with organic P hydrolysis or the release of P from colloids during P investigation, which leads to a difference of ortho-phosphate concentrations determined by IC and molybdenum blue methods. During the environmental samples analysis, the ortho-phosphate obtained by the IC method was usually less than that obtained by the molybdenum blue method.     

Efficiency of two widespread non-destructive extraction methods under dry soil conditions for different ecological earthworm groups

Reliable non-destructive extraction methods are required for the assessment of the size and composition of earthworm communities where physical disturbances are not acceptable. The aim of the present study was to investigate the efficiency of the electrical octet method and the mustard extraction method for sampling of different ecological groups of earthworms (anecics, endogeics and epigeics) under dry soil conditions. We hypothesized that: (1) the extraction efficiency of the mustard method and the octet method will vary with ecological earthworm group; and (2) beforehand water addition to dry soil will increase the extraction efficiency of the octet method but not that of the mustard method.Endogeic earthworm species were extracted in low numbers irrespective of the extraction method indicating their inactivity during dry periods. The mustard method was more efficient for the extraction of anecic earthworms even under dry soil conditions, whereas the octet method was inappropriate in reflecting the actual earthworm community structure. Surprisingly, the efficiency of both methods was not improved by beforehand water addition. These findings are essential to be considered when working under dry soil conditions e.g. in the context of environmental monitoring.     

Inefficiency of mustard extraction technique for assessing size and structure of earthworm communities in UK pasture

An assessment of the efficiency of the mustard extraction method to quantify the total earthworm community structure on UK earthworms was carried out on a permanent pasture in Bedfordshire, UK. Earthworms were collected using mustard extraction and control treatments. Numbers and community structure of worms expelled from soils after surface applications of expellants were determined, and underlying soil from each replicate was hand-sorted to recover residual earthworms. The mustard-based treatment was the only method to expel earthworms to the surface, and 35.7% of the extant population emerged. The apparent earthworm community structures expelled indicated that mustard extraction was biased towards large, sexually mature anecic earthworms. This is likely due to the connectivity of burrows of these earthworms to the surface and hence a biased incursion of mustard solution down such channels. The mustard extraction technique is therefore inappropriate where accurate assessment of earthworm communities is required.     

Comparison of some methods for determination of sulfate in soils

Abstract

Sulfate (SO₄ ^2‐) is present in soils as salts of various metals, and the different metals associated with sulfate may influence adsorption of SO₄ ^2‐by soils. The analytical method used for determination of SO₄ ^2‐could be affected by the type of metal associated with the SO₄ ^2‐. Four analytical methods based on different principles were evaluated for determination of SO₄ ^2‐in different metal salts and in soil extracts obtained with three extractants {0.1M lithium chloride (LiCl), 0.15% calcium chloride (CaCl₂), and 500 mg P/L as calcium phosphate [Ca(H₂PO₄)2]}. The analytical methods were: (i) a methylene blue (MB) colorimetric method after the reduction of SO₄ ^2‐to hyrogen sulfide (H₂S), (ii) an ion Chromatographie (IC) method, (iii) a turbidimetric (TD) method, and (iv) an indirect barium (Ba) atomic absorption spectrophotometric (SP) method. The recovery of SO₄ ^2‐associated with various mono‐, di‐, and tri‐valent metals was quantitative by the MB method. But, trivalent metals, such as aluminum (Al), indium (In), lanthanum (La), and scandium (IC), decreased the recovery of SO₄ ^2‐by the other three methods. The MB and IC methods gave similar values for SO₄ ^2‐in soils by using the three extractants. The TD and SP methods gave variable results and, in general, underestimated the amounts of SO₄ ^2‐in soils. Among the four methods, the MB and IC methods were the most accurate and precise.     

土壤无机阴离子的毛细管电泳分析

采用以铬酸钠为背景电解质、十六烷基三甲基溴化铵为电渗流改性剂的间接紫外检测法电泳系统 ,研究了分离电压、缓冲液的酸碱性等毛细管电泳测定氯离子、硫酸根、硝酸根和磷酸根的基本条件 ,可在 5min内对以上 4个离子实现准确定量。测定了 5个采自全国不同地区的土壤样品水提取液中的无机阴离子。结果显示 ,毛细管电泳可对提取液中的氯离子、硫酸根和硝酸根实现较准确的定量 ,测定结果与离子色谱比较一致 ;对硝态氮的测定结果与KCl提取 流动分析结果相关性达到p <0 10水平 ,表明测定结果可在一定程度上反映土壤氮素养分状况。但土壤用水静止提取 2 4h ,提取液中的磷未达到毛细管电泳和离子色谱法的检测限 ,毛细管电泳的测定精确度不及离子色谱     

采用多光谱图像融合提高作物和杂草灰度比值

作物和杂草在图像中的灰度比值对识别率有着重要的影响。提出了一种利用多光谱图像融合的方法提高它们在图像中的灰度比值。为了采用多光谱图像,研制了基于黑白摄像机和多种滤光片的计算机控制的多光谱图像采集系统。在对洋葱(作物)、野芥末草(杂草)和土壤在多光谱图像中灰度比值研究的基础上,对多种多光谱图像融合方式进行了对比试验研究,发现以b+ir-g-r等图像融合方式给出了比较好的结果。把这些图像融合方式应用到图像识别中,其结果表明,多光谱图像融合方法比仅采用彩色分量的融合方法,其识别误差减少了22％。文中同时给出了评价作物、杂草和土壤在图像中灰度比值指标的方法。     

Utilization of Petrochemical Industry Waste Water for Agriculture

Field experiments were conducted to evaluate the impact of petrochemical industry waste water on certain physico-chemical properties of soil and on growth, yield and quality of corn (Zea mays L.) and mustard (Brassica juncea L. Czern and Coss). The pH of the waste water was near about neutral but it contained a higher amount of nitrogen, potassium, phosphate, sodium, chloride, calcium, carbonates, bicarbonates and suspended and dissolved solids when compared with fresh water. Soil receiving the waste water showed no significant changes in water soluble salts, electrical conductivity, cation exchange capacity, pH, total organic carbon etc. Moreover, waste water irrigation resulted in increased growth and yield of both the crops. Thus, it may be concluded that the petrochemical industry waste water may be used profitably for the cultivation of corn and mustard.     

A new method to measure allyl isothiocyanate (AITC) concentrations in mustard—Comparison of AITC and commercial mustard solutions as earthworm extractants

Earthworms are target organisms both for scientists studying the biological component of soils and for farmers concerned with monitoring the quality of their soils. Different expellants are used to extract earthworms from the soil but differences in chemical properties and efficiency between commercial mustard and allyl isothiocyanate (AITC) solutions remain unknown. The objectives of this study were to compare (i) the concentration of irritating product (allyl isothiocyanate AITC) in two expellant solutions (diluted mustard or AITC solution) and (ii) their efficiency in extracting earthworms from the soil.AITC concentration was analyzed according to a new method, based on AITC solvent extraction and HPLC quantification, in one commercial mustard brand to assess its variability within and between batches of jars. According to mustard spiking with AITC standard solution, extraction recovery was estimated as 98 ± 2%. Earthworm field data were collected in spring 2012 in 22 cultivated fields located in east Île-de-France, comparing pure AITC to commercial mustard solutions. Species diversity, abundance and biomass of earthworms per plot were measured.We showed that AITC concentration in commercial mustard varied according to the use by date but not according to the batch. We thus recommend using the freshest mustard available from the same batch. Moreover, AITC solution was found to be about four times more concentrated in AITC than the commercial mustard solution. Despite this result, no significant differences were found in the efficiency of commercial mustard or AITC solutions to bring earthworms to the soil surface in terms of abundance, biomass or diversity. We thus discuss the advantage and drawbacks of using both expellants in the field.     

Comparison of the Volhard and potentiometric methods for the determination of chloride in meat products: collaborative study

A collaborative study of the determination of chloride in meat products was conducted by the International Organization for Standardization (ISO) to compare the ISO 1841 method (Volhard titration) with the FAO/WHO Codex Alimentarius Committee method (potentiometric titration). Five canned luncheon meat products containing 0.25-2.0% sodium chloride at 4 different spiking levels were analyzed by 11 laboratories. The data were analyzed by ISO statistics (ISO 5725) and by AOAC statistics (Youden-Steiner), the major differences being in the rejection of outliers and in the statement of precision parameters. Good agreement was found between the mean chloride contents of the products as determined by both methods and with the added amounts, although statistically significantly higher sodium chloride recoveries were obtained with the potentiometric method. The within-laboratory variability (repeatability) is greater for the Volhard method, especially for chloride levels below 1.0%. Therefore it is proposed to set the lowest level of determination for the Volhard method at about 1.0% sodium chloride. The among-laboratories variability (reproducibility) of the potentiometric method was comparable with the results from the collaborative studies for chloride in cheese, giving acceptable values for relative standard deviations of 1.5-3.0% for meat products with 0.3-2.0% added sodium chloride. It is recommended that further work be conducted to reduce or eliminate the systematic error present with the potentiometric method as applied to meat and meat products.     

Rat lens aldose reductase inhibitory activities of Coptis japonica root-derived isoquinoline alkaloids

The inhibitory activity of Coptis japonica root-derived materials was evaluated against lens aldose reductase isolated from male Sprague-Dawley rats and compared to that of three commercially available isoquinoline alkaloids (berberine sulfate, berberine iodide, and palmatine chloride), as well as quercitrin as aldose reductase inhibitor. The biologically active constituents of C. japonica extract were characterized as the isoquinoline alkaloids, berberine chloride and palmatine iodide, by spectral analysis. The inhibitory effects varied with both chemical and concentration used. The IC(50) values of berberine chloride and palmatine iodide are 13.98 and 13.45 nM, respectively. Among three berberines and two palmatines, the inhibitory activity was much greater for the choridated and sulfated analogues than for those with iodide. Quercitrin was a much more potent inhibitor than berberines and palmatines. Nonetheless, berberines and palmatines may be useful as lead compounds and new agents for aldose reductase inhibition.     

Determination of total sulfur in soils and plant materials by ion chromatography

Abstract

An accurate and precise ion Chromatographie (IC) method is described for determination of total S in soils and plant materials. It involves ignition of a mixture of soil and NaHCO₃or plant material and NaHCO₃containing Ag₂O at 550°C for 3 h. The residue is dissolved in 1MHOAc, diluted with deionized water, filtered, and analyzed for S0^2‐ ₄by a Dionex model 2002i ion Chromatograph. Results by the IC method of seven Iowa soils, three Chilean soils, and 10 plant materials agreed closely with those obtained by the methylene blue method after alkaline oxidation with NaOBr. In general, the IC method was more precise than the methylene blue method. The method is simple and requires a minimum of analytical skill. A single operator can analyze 30–40 soil or plant samples in a normal working day.