Selenium concentrations of common weeds and agricultural crops grown in the seleniferous soils of northwestern India

The plants grown in seleniferous soils constitute a major source of toxic selenium levels in the food chain of animals and human beings. Greenhouse and field experiments were conducted to study selenium concentrations of weeds, forages and cereals grown on seleniferous soils located between 31.0417° to 31.2175° N and 76.1363° to 76.4147° E in northwestern India. Eleven winter season (November-April) weed plants were grown in the greenhouse in a soil treated with different levels of selenate-Se. Selenium concentrations of weed plants increased progressively with the levels of selenate-Se in soil. The highest Se concentration was recorded by Silene gallica (246 mg kg^− 1) and the lowest by Avena ludoviciana (47 mg kg^− 1) at 2.5 mg Se kg^− 1 soil. A.ludoviciana and Spergula arvensis proved highly tolerant to the presence of 1.25 and 2.5 mg selenate-Se kg^− 1 soil and the remaining weeds were sensitive to Se. Dry matter yield of Se-sensitive weed plants was 25 to 62% of the yield in the no-Se control at 1.25 mg selenate-Se kg^− 1 and 6 to 40% at 2.5 mg selenate-Se kg^− 1 soil. Other symptoms like change in leaf colour and size, burning of leaf tips and margins, and delayed flowering were also observed due to Se. Dry matter yield of Se-sensitive weed plants expressed as percentage of yield in the no-Se control at both the Se levels was inversely correlated with their Se content (r = − 0.731, p < 0.01, N = 17). Among the weed plants grown in seleniferous soils under field situations, Mentha longifolia accumulated the highest Se (365 mg kg^− 1) and Phalaris minor the lowest (34 mg kg^− 1). Among agricultural crops grown on a naturally contaminated soil in the greenhouse, Se concentrations were the highest for oilseed crops (19-29 mg kg^− 1), followed by legumes (6-13 mg kg^− 1) and cereals (2-18 mg kg^− 1). Helianthus annuus among the oilseed crops, A.ludoviciana among the winter season weeds, M.longifolia among the summer season (May-October) weeds and Cirsium arvense among the perennial weeds can be used for phytoremediation of seleniferous soils as these accumulate the highest amounts of Se.     

我国绿色粮库建设现状与展望

粮库是粮食流通的核心设施,目前我国有18 200个粮库、3.7亿t仓容,粮食收储规模超过了年总产量的一半,粮食储藏技术也从减损降耗、保质安全逐渐向绿色健康、低碳环保的方向转变。从粮库设施设备、粮食仓储技术和粮库系统管理机制等层面分析绿色粮库建设的现状和发展前景,为促进粮食产后仓储业健康发展提供参考。     

Carotene content of some common (cereals,pulses, vegetables,spices and condiments) and unconventional sources of plant origin

This study provides new data on the the total carotenoids and β-carotene content of commonly consumed cereals, pulses, vegetables, spices and condiments. Separation of carotenoids by HPLC showed that β-carotene is the predominant carotenoid in all the foods studied. Cereals and pulses appear to be poor sources of provitamin A precursors. Among the vegetables studied pumpkin, ridge gourd, green chillies, tomato, green peas, field beans and French beans are not only inexpensive but are better sources of β-carotene (20–120 mg/100 g). Among the spices and condiments, red chilli (1310 mg/100 g) and Smilax (2136 mg/100 g), which are regularly used in Indian recipes are good sources of provitamin A precursors. The study also identified unconventional sources like Gulmohar, Peltiforum ferruginum,Lucern and Spirulina as rich sources of β-carotene. Considering that Indian diets predominantly consist of cereals and pulses, choosing appropriate combinations of cereals and pulses will contribute significantly to overall vitamin A intakes. Together with our earlier efforts, the present study has generated a database of β-carotene contents of Indian plant foods, which could be of help in the elimination of vitamin A deficiency.     

Fusarium species and fumonisins in subsistence maize in the former Transkei region,South Africa: a multi-year study in rural villages

Fumonisin occurrence was investigated in subsistence maize in four rural villages in each of Mbizana and Centane areas, South Africa. Samples (total 211) were analysed morphologically for Fusarium species and by high performance liquid chromatography for fumonisins. The mean incidence levels of Fusarium verticillioides in Centane good maize were 16% for both 1997 and 2000, but increased to 32% in 2003, whereas Mbizana good maize contained levels of 17% and 11% (2000 and 2003 seasons, respectively). The mean total fumonisin level in good maize in Centane for 1997 and 2000 was 575 and 975 µg/kg and 2150 µg/kg in 2003. In Mbizana, the mean total fumonisin level in good maize for 2000 was 950 µg/kg, but decreased to 610 µg/kg in 2003. The 2003 drought conditions led to a substantial increase in fumonisin levels in dry subhumid Centane, compared to humid subtropical Mbizana. This study emphasises the seasonal fluctuation in fumonisin levels.     

A new solid phase extraction clean-up method for the determination of 12 type A and B trichothecenes in cereals and cereal-based food by LC-MS/MS

A new reliable and cost-efficient solid phase extraction-based clean-up method for the determination of 12 type A and B trichothecenes [deoxynivalenol (DON), nivalenol, 3-acetyldeoxynivalenol, 15-acetyldeoxynivalenol, fusarenon-X, T-2 toxin, HT-2 toxin, neosolaniol, monoacetoxy-scirpenol, diacetoxyscirpenol, T-2 triol and T-2 tetraol] in cereals and cereal-based food is presented. Furthermore, the suitability for the simultaneous determination of zearalenone is examined. Toxins were extracted from cereal samples using ACN/water (80/20, v/v), purified by means of a new Bond Elut Mycotoxin column and analyzed via liquid chromatography-electrospray ionization tandem mass spectrometry. Limits of detection were calculated for the matrix wheat and ranged from 0.3 to 5 ng/g, depending on the toxin. Average recovery rates for the tested compounds in seven cereal-based matrices have been determined ranging from 65 to 104%. The relative standard deviations of the complete method ranged from 2.67 (DON, wheat) to 20.0% (T-2 toxin, oats).     

Adaptability of lactic acid bacteria and yeasts to sourdoughs prepared from cereals, pseudocereals and cassava and use of competitive strains as starters

The adaptability of lactic acid bacteria (LAB) and yeasts to sourdoughs prepared from cereals, pseudocereals and cassava was investigated using PCR-DGGE and bacteriological culture combined with rRNA gene sequence analysis. Sourdoughs were prepared either from flours of the cereals wheat, rye, oat, barley, rice, maize, and millet, or from the pseudocereals amaranth, quinoa, and buckwheat, or from cassava, using a starter consisting of various species of LAB and yeasts. Doughs were propagated until a stable microbiota was established. The dominant LAB and yeast species were Lactobacillus fermentum, Lactobacillus helveticus, Lactobacillus paralimentarius, Lactobacillus plantarum, Lactobacillus pontis, Lactobacillus spicheri, Issatchenkia orientalis and Saccharomyces cerevisiae. The proportion of the species within the microbiota varied. L. paralimentarius dominated in the pseudocereal sourdoughs, L. fermentum, L. plantarum and L. spicheri in the cassava sourdough, and L. fermentum, L. helveticus and L. pontis in the cereal sourdoughs. S. cerevisiae constituted the dominating yeast, except for quinoa sourdough, where I. orientalis also reached similar counts, and buckwheat and oat sourdoughs, where no yeasts could be detected. To assess the usefulness of competitive LAB and yeasts as starters, the fermentations were repeated using flours from rice, maize, millet and the pseudocereals, and by starting the dough fermentation with selected dominant strains. At the end of fermentation, most of starter strains belonged to the dominating microbiota. For the rice, millet and quinoa sourdoughs the species composition was similar to that of the prior fermentation, whereas in the other sourdoughs, the composition differed.     

Comparison of isolation methods for the determination of buckwheat volatile compounds

Five different isolation techniques were combined with gas chromatographic–mass spectrometric determination of aroma compounds from buckwheat: dynamic headspace (DHS) with cryotrapping or sorbent trapping, solid-phase microextraction (SPME), headspace sorptive extraction (HSSE), solvent extraction (SE) and simultaneous distillation–extraction (SDE). Optimisation of each technique is presented, as well as comparison of the chemical profiles obtained by them. Solvent extraction with methanol resulted in the isolation of rather polar and less volatile compounds and was deemed least suitable for the odour-active compounds. Only SPME with DVB/CAR/PDMS fibre was suitable for the isolation of highly volatile compounds in a wider polarity range. DHS extracted the smallest number of compounds, but with the comparable chemical profile as obtained by SDE, which was chosen as the most suitable technique to obtain the aroma compounds of cooked buckwheat. The applied isolation techniques are complementary in their ability to extract a representative aroma profile of buckwheat.     

TG–DTA approach for designing reference methods for moisture content determination in food powders

There is no systematic procedure described in the literature to establish a robust and accurate reference method for determining the moisture content in any solid food product. In this paper, we are proposing a new approach based on simultaneous thermogravimetry and differential thermal analysis (TG–DTA), with data for several amorphous food powders that result from spray-drying, freeze-drying or extrusion. In the first step, by heating a representative sample of about 20 mg at 2 °C/min we would detect the temperature and the mass loss at the inflection point that characterises, if there is an inflection, the end of the drying and the onset of chemical reactions. In cases of not too much sensitive products, the mass loss at the inflection may be considered as a good estimation of the moisture content. At 2 °C/min heating rate, the inflection temperature T_i is an indicator that allows estimating the optimal isothermal drying temperature T_d about 15–30 °C below T_i, depending on the product sensitivity to heat treatments and the kinetics of water molecule diffusion through the amorphous matrix. Then, a series of three isothermal drying are performed at about T_d−12 °C, T_d and T_d+8 °C, and a simple multilinear model allows calculating the best oven temperature to achieve the optimal moisture content determination in 2 h. This procedure is described and results are shown for several dehydrated food products: milk, coffee, cereal and pet food. This fast procedure may be applied either for establishing optimal oven conditions for most amorphous new products or for revising conditions that have been established in the past but are not robust enough for several ones.     

Effect of fermentation on antioxidant properties of some cereals and pseudo cereals

The influence of fermentation by two types of microorganisms (lactic acid bacteria Lactobacillus rhamnosus, and yeast Saccharomyces cerevisiae) on antioxidant activities and total phenolics of 4 cereals, namely buckwheat, wheat germ, barley and rye, was determined and compared with those of their unfermented counterparts. The total phenolic content (TPC), determined by the Folin–Ciocalteu method, increased upon fermentation. Antioxidant activities (AOA) were assessed using 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging capacity, ferric ion-reducing antioxidant power (FRAP) and thiobarbituric acid (TBA) methods. The presence of those microorganisms was more or less important for enhanced levels of antioxidant activity. Thus fermentation offers a tool to further increase the bioactive potential of cereal products.     

Effect of the degree of fusariosis on the physical characteristics of individual wheat kernels

This work aims to determine dependencies of single‐kernel (SK) physical traits on the kernel degree of fusariosis. The measurements were taken on samples of grain of six wheat varieties cultivated during 1–3 years. For SK mass, volume and width this dependence resulted in lowered (by at least ten to more than 25% for mass and volume, and ca. 5 to more than 15% for width) values in Fusarium culmorum infested grain as compared with the non‐inoculated control. In addition, moderately infested kernels tended to be of higher mass and size than kernels with no symptoms of infestation. An unexpected effect was a lack of dependence of SK density on the degree of infestation. Moisture content was lower for infested kernels by 6–8%, hardness tended to increase a little for moderate infestation, while it noticeable decreased for the heaviest infestation.