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101.
Gustavo Brunetto Alcione Miotto Carlos Alberto Ceretta Djalma Eugênio Schmitt Janaína Heinzen Marcel Pires de Moraes 《Archives of Agronomy and Soil Science》2013,59(5):609-624
The purpose of this study was to evaluate the mobility of copper (Cu) and zinc (Zn) in the profile and distribution of sandy soil fractions from vineyards. Soil samples were collected from two vineyards of different ages (14 and 30 years) and a natural field area in the south of Brazil. The chemical characteristics, Cu levels and Zn levels, were analyzed in the soils by extraction with ethylenediamine tetraacetic acid (EDTA) using the 3050B method of USEPA and by chemical fractionation. Cu and Zn were accumulated in the vineyard soils, especially in the uppermost soil layers and in the soil from the oldest vineyard. Approximately, 75% of the total Cu was extracted by EDTA, but only 30% of the total Zn was extracted by EDTA. Most of the Cu, especially in the oldest vineyard, was distributed in the mineral-associated fraction, which is characterized by low geochemical mobility, but another important part of the Cu was distributed in the soil organic matter. Most of the Zn in the soil was distributed in the residual and mineral-associated fractions, which are characterized by low mobility and have potential for causing toxicity to plants. 相似文献
102.
103.
Hruzikova J Milde D Krajancova P Ranc V 《Journal of agricultural and food chemistry》2012,60(7):1845-1849
Quality and authenticity control serve as the customers' and manufacturers' insurance, and thus the development of analytical tools providing these tasks represents an important step of each product development. The control of authenticity in food manufacturing is even more important due to the direct influence of its products on the health of the population. This study sought to develop an easy to use and robust method for the authenticity control of cheese products. The method is based on the measurement of infrared spectra of the gas phase obtained by heating of selected cheese under controlled conditions. Two different procedures, that is, treatment of samples in a desiccator and their freeze-drying, were compared, and also various temperatures and heating times were studied. It was found that suitable fingerprint infrared spectra can be obtained by both techniques; however, freeze-drying offered faster analysis times. The sample heating temperature and time were evaluated using advanced statistical approaches, and it was found that suitable results could be obtained using 120 °C heating for 90 min. This method was tested for the authenticity control of two cheese families, Tvaruzky and Romadur, for which four cheese products were evaluated and successfully discriminated for each family. This method can be potentially used as a cheap and easy to use alternative to other commercially available options. 相似文献
104.
Konečná H Müller L Dosoudilová H Potěšil D Buršíková J Sedo O Márová I Zdráhal Z 《Journal of agricultural and food chemistry》2012,60(10):2418-2426
Two-dimensional gel electrophoresis in combination with mass spectrometry has already been applied successfully to study beer proteome. Due to the abundance of protein Z in beer samples, prefractionation techniques might help to improve beer proteome coverage. Proteins from four lager beers of different origins were separated by two-dimensional electrophoresis (2-DE) followed by tandem mass spectrometric analysis. Initially 52 proteins mostly from Hordeum vulgare (22 proteins) and Saccharomyces species (25 proteins) were identified. Preparative isoelectric focusing by OFFGEL Fractionator was applied prior to 2-DE to improve its resolution power. As a result of this combined approach, a total of 70 beer proteins from Hordeum vulgare (30 proteins), from Saccharomyces species (31 proteins), and from other sources (9 proteins) were identified. Of these, 37 proteins have not been previously reported in beer samples. 相似文献
105.
Deoxynivalenol oligoglycosides: new "masked" fusarium toxins occurring in malt, beer, and breadstuff
M Zachariasova M Vaclavikova O Lacina L Vaclavik J Hajslova 《Journal of agricultural and food chemistry》2012,60(36):9280-9291
The co-occurrence of deoxynivalenol-3-glucoside with its parent toxin, deoxynivalenol, has been recently documented in many cereal-based foods, especially in those produced by enzyme-catalyzed processes. The presence of this masked mycotoxin in the human diet has become an issue of health concern, mainly because of its assumed bioavailability. A selective immunoaffinity-based preconcentration strategy, followed by ultrahigh-performance liquid chromatography coupled with high-resolution orbitrap mass spectrometry, revealed that, in addition to the most common deoxynivalenol-3-glucoside, also oligoglycosylated deoxynivalenols with up to four bound hexose units were present in cereal-based products. The structure, origination, and fate of these deoxynivalenol conjugates during malt/beer production and bread baking have been thoroughly investigated. Special attention has been paid to the changes of deoxynivalenol conjugates enabled by industrial glycosidase-based enzymatic preparations. To the authors' best knowledge, this is the first study documenting the complexity of masked deoxynivalenol issue. 相似文献
106.
AnnaLotta Schiller Vestergren Sofia Trattner Jinfeng Pan Pernilla Johnsson Afaf Kamal-Eldin Eva Brännäs Ali A. Moazzami Jana Pickova 《Aquaculture International》2013,21(4):843-859
Sesamin (S) is a known lipid modulator and has been shown to increase the conversion of α-linolenic acid (ALA) to docosahexaenoic acid in rainbow trout (Oncorhynchus mykiss) fed vegetable oil mixtures including linseed oil. In this study, we evaluated the effects of S supplementation in linseed oil-based diets, content of α- and γ-tocopherols, fatty acid (FA) composition, as well as the gene expression of lipid-related genes. Fish with an average weight of 36.5 g were fed different combinations of commercial linseed oil (LO), purified linseed oil triacylglycerols (TAG) with polar fraction removed and a mixed linseed-sunflower oil (6:4 v/v) (MO). S was added at 0.58 g 100?1g feed and fed to the fish for a period of 58 days. Expression of PPARα was downregulated in white muscle of fish fed S containing diets (P < 0.05). The expression of PPARβ1A was not affected by S supplementation except where TAG oil was used. The expression of PPARβ1A declined significantly in TAG + S fed group (P < 0.05), which indicates that some minor compounds in linseed oil might suppress the effect of S on the expression of PPARβ1A. The expression of PPARγ(long) declined in LO + S and MO + S fed group (P < 0.05). The β-oxidation-related genes CPT1 and ACO were upregulated by vegetable oils compared to fish oil. S decreased percentage of ALA in white muscle of fish fed LO + S (P < 0.05). The increased desaturation index and the decreased ALA levels suggest that S may increase the biosynthesis of highly unsaturated FA in rainbow trout. 相似文献
107.
Polyurethane-based side-chain cholesteric liquid crystalline polymers (ChLCPs) with variable clearing temperatures were synthesized
in a two-step reaction. The chemical structures of ChLCPs were confirmed by FT-IR and 1H-NMR spectroscopy. The mesogenic properties and phase transition behavior were investigated by means of differential scanning
calorimetry (DSC), polarizing optical microscopy (POM), and X-ray diffraction measurements. The DSC studies show that the
melting temperature and isotropic transition temperature of the ChLCPs increased with the weight percentage of cholesterol
in the polymer. POM shows that the ChLCPs had a distinct spherulite structure that melted at about 140 °C, and these results
are consistent with those of the DSC studies. The thermogravimetric studies show that the ChLCPs were stable up to 200 °C,
though there was a reduction in the thermal stability as the weight proportion of cholesterol and glycerol in the polymer
increased. 相似文献
108.
In Europe, farmers are encouraged to reduce pesticide use. Pesticide use intensity in arable farming depends on many factors. Numerous studies report a high variance in pesticide use between farms. The aim of the present study is to identify farm specific determinants for the intensity of pesticide use. We investigated which farm characteristics and pesticide management factors are related to lower or higher pesticide use intensity. Data on chemical plant protection measures of 30 farms in two districts of North East Germany were examined for five field crops from 2005 until 2014. In the present study we investigated the pesticide use intensities described as Standardized Treatment Index (STI) of ten representative farms. Yield data and information on the field-specific soil quality were available from these ten farms. We used multiple regressions to estimate the relationship between farm characteristics and pesticide use. 相似文献
109.
110.