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41.
Díaz P Señoráns FJ Reglero G Ibañez E 《Journal of agricultural and food chemistry》2002,50(22):6468-6472
An experimental design has been used to optimize the extraction of volatile compounds from summer truffle aroma (Tuber aestivum) by using headspace solid phase microextraction. The extracted compounds have been analyzed by gas chromatography with a flame ionization detector and by gas chromatography-mass spectrometry (GC-MS). In an attempt to develop an objective method to fully characterize truffle aroma, a fiber of medium polarity (for flavors) was used to avoid discrimination toward very nonpolar and polar volatile compounds. To optimize the extraction conditions, a response surface experimental design was applied considering three factors such as extraction temperature, equilibrium time, and extraction time. From the statistical analysis of the experimental design, it was possible to determine that the most important factor influencing the abundance of aroma compounds was the extraction temperature. Optimal extraction temperature was established at approximately 50 degrees C. By using GC-MS, it was possible to identify 37 compounds, most of them previously described as responsible for truffle aroma. 相似文献
42.
Leontowicz M Gorinstein S Leontowicz H Krzeminski R Lojek A Katrich E Cíz M Martin-Belloso O Soliva-Fortuny R Haruenkit R Trakhtenberg S 《Journal of agricultural and food chemistry》2003,51(19):5780-5785
The aim of this study was to assess the bioactive compounds of apple and pear peel and pulp in vitro and their influence on plasma lipids and antioxidant potentials in vivo. The antioxidant potentials measured by 1,1-diphenyl-2-picrylhydrazyl (DPPH), beta-carotene bleaching (beta-carotene), and nitric oxide inhibition radical scavenging (NO) tests in apple peel and pulp were significantly higher than in pear peel and pulp, respectively. The ethanol extract of apple peels showed the strongest inhibition of lipid peroxidation as a function of its concentration and was comparable to the antioxidant activity of butylated hydroxyanisole. The pear pulp extract had the weakest antioxidant ability, whereas other extracts such as apple pulp and pear peel were nearly equal. The antioxidant activities comprised contributions from polyphenols, phenolic acids, and flavonoids and correlated well with polyphenols and flavonoids. The correlation coefficients between polyphenols and antioxidant activities by DPPH, beta-carotene, and NO were as follows: 0.9207, 0.9350, and 0.9453. Contrarily, the correlation coefficient between the content of dietary fiber and the antioxidant activities test was low. The content of all studied indices in apple and pear peel was significantly higher than in peeled fruits (p < 0.05). Diets supplemented with fruit peels exercised a significantly higher positive influence on plasma lipid levels and on plasma antioxidant capacity of rats than diets with fruit pulps. 相似文献
43.
Yelena V. Lyubun Paul V. Kosterin Elena A. Zakharova Alexander A. Shcherbakov Evgenii E. Fedorov 《Journal of Soils and Sediments》2002,2(3):143-147
Background, Aim and Scope Environmental pollution caused by arsenic (As) is a major ecological problem. There has been intense worldwide effort to find
As-hyperaccumulating plants that can be used in phytoremediation—the green-plant-assisted removal of chemical pollutants from
soils. For phytoremediation, it is natural to prefer cultivated rather than wild plants, because their agriculture is well
known. This study was conducted to evaluate the tolerance of common sunflower(Helianthus annuus L.) and sugar sorghum(Sorghum saccharatum Pers.) for soil-As contents of 10–100 mg As kg-1 soil, with sodium arsenite as a model contaminant.
Methods Plants were grown in a growth chamber for 30 days. Microfield experiments were conducted on experimental plots. To study the
phytoremediation effect of the auxins indole-3-acetic acid (IAA) and 2,4-dichlorophenoxyacetic acid (2,4-D), we treated 1-
and 3-day-old plant seedlings with water solutions of the auxins (concentrations 10-5, 10-7, and 10-9 g l-1). The soil and plant-biomass samples were analyzed for total As by using the color reaction of ammonium molybdate with As.
Results and Discussion Phytotoxicity studies showed that 100 mg As kg-1 soil poisoned sunflower and sorghum growth by 50%. There was a linear correlation between soil-As content and As accumulation
in the plants. Laboratory experiments showed that the soil-As content was reduced two- to threefold after sunflower had been
grown with 10–100 mg As kg-1 soil for 30 days. Treatment of sunflower and sorghum seedlings with IAA and 2,4-D at a concentration of 10-5 g l-1 in microfield experiments enhanced the phytoremediation two- to fivefold as compared with untreated control plants. The best
results were obtained with 3-day-old seedlings.
Conclusion, Recommendation and Outlook (a) Sunflower and sorghum are good candidates to remediate As-polluted soils. (b) Phytoremediation can be improved with IAA or 2,4-D. (c) Mixed cropping of sorghum and sunflower may be another way of improving phytoremediation. 相似文献
44.
Elena N. Tokareva Andrey V. Pranovich Bjarne R. Holmbom 《Wood Science and Technology》2011,45(4):767-785
Different model compounds for lignin, hemicelluloses and pectins were studied by time-of-flight secondary-ion mass spectrometry
(ToF–SIMS). Mass spectra of Klason lignin from normal and compression spruce wood, aspen wood and wheat straw were compared.
Spectra of brominated spruce and aspen wood sections showed fragment ions attributed to brominated guaiacyl and syringyl units
in lignin at m/z 215, 217, 229 and 231, and m/z 245, 247, 249 and 261, respectively. Spectra of mono-, oligo- and polysaccharides
showed fragment ions at m/z 127 and 145 characteristic for hexose units, and ions at m/z 115 and 133 characteristic for pentose
units. The same ions were detected in spectra of delignified spruce and aspen wood sections. Labelling of anionic groups by
Sr2+ ions followed by ToF–SIMS analysis showed that pectins were present at specific locations on the surfaces of spruce and aspen
wood sections still after delignification with hydrogen peroxide in acetic acid. 相似文献
45.
46.
Victoria González-Rodríguez Rafael Villar Raquel Casado Elena Suárez-Bonnet José Luis Quero Rafael M. Navarro-Cerrillo 《Annals of Forest Science》2011,68(7):1217-1232
Introduction
The great spatial and temporal heterogeneity of Mediterranean ecosystems can influence establishment success in woody species, whose natural regeneration occurs to a very small extent. In this work, the effect of the spatial pattern of environmental variables (light availability, soil moisture and herbaceous production) on seedling emergence, growth, survival and establishment success was examined by using a spatially explicit approach. 相似文献47.
Determination of Ploidy Level and Nuclear DNA Content in Tunisian Populations of Atriplex halimus L.
Kheiria Hcini David J. Walker Sadok Bouzid Elena González Nora Frayssinet Enrique Correal 《Genetic Resources and Crop Evolution》2006,53(1):1-5
Atriplex halimus L. (Chenopodiaceae) (Saltbush) is a perennial species used as a fodder shrub for livestock in arid and semi-arid areas, particularly
in North Africa. The aim of this work was to determine whether differences in ploidy level and/or nuclear DNA content exist
among populations from widely-separated sites in Tunisia. We determined nuclear DNA content and chromosome numbers for populations
of A. halimus from seven different locations (Gabes, Medenine, Tataouine, Monastir, Tunis, Sidi Bouzid, Kairouan). The chromosome counts
showed that all the Tunisian populations, plus a population from Eraclea (Italy), were tetraploid (2n = 4x = 36) whereas a population from Cala Tarida (Spain) was diploid (2n = 2x = 18). With respect to nuclear DNA, the 2C DNA content of population Cala Tarida was estimated to be 2.41 pg. There was no
significant difference among the tetraploid populations (or among plants within populations), whose 2C DNA content ranged
from 4.92 to 4.97 pg. 相似文献
48.
Magni C Ballabio C Restani P Sironi E Scarafoni A Poiesi C Duranti M 《Journal of agricultural and food chemistry》2005,53(6):2275-2281
The allergenicity of seed storage proteins, the major components of edible legume seeds, may cause serious reactions in both children and adult population. Updated methodologies for evaluation of the activity of these proteins are needed. In this paper we used two-dimensional (2D) electrophoretic techniques to investigate the immuno-cross-reactivities of anti Ara h 3 basic subunit IgG to the seed proteomes of three legume species, namely, peanut, soybean, and lupin. The seed proteins, extracted with two different procedures, were separated by 2D electrophoresis, and the electrophoretic maps were analyzed by Western blot. In peanut proteome the antibodies strongly reacted with the 23 kDa polypeptides, corresponding to Ara h 3 basic isoforms, the antigen they were raised to, and three unidentified acidic polypeptides near 45 kDa. Remarkable cross-reactivities with lupin and soybean Ara h 3 homologous polypeptides and nonrelated proteins, namely, lupin conglutin gamma and soybean Bg7S, were detected. Therefore, these proteins may be regarded as new putative allergens. The present findings show the potentiality of 2D electrophoresis in the identification of food allergens and open the way to the traceability of the new cross-reacting proteins in the food chain. 相似文献
49.
We present here an indicator of soil quality that evaluates soil ecosystem services through a set of 5 subindicators, and further combines them into a single general Indicator of Soil Quality (GISQ). We used information derived from 54 properties commonly used to describe the multifaceted aspects of soil quality. The design and calculation of the indicators were based on sequences of multivariate analyses. Subindicators evaluated the physical quality, chemical fertility, organic matter stocks, aggregation and morphology of the upper 5 cm of soil and the biodiversity of soil macrofauna. A GISQ combined the different subindicators providing a global assessment of soil quality.Research was conducted in two hillside regions of Colombia and Nicaragua, with similar types of land use and socio-economic context. However, soil and climatic conditions differed significantly. In Nicaragua, soil quality was assessed at 61 points regularly distributed 200 m apart on a regular grid across the landscape. In Colombia, 8 plots representing different types of land use were arbitrarily chosen in the landscape and intensively sampled. Indicators that were designed in the Nicaragua site were further applied to the Colombian site to test for their applicability.In Nicaragua, coffee plantations, fallows, pastures and forest had the highest values of GISQ (1.00; 0.80; 0.78 and 0.77, respectively) while maize crops and eroded soils (0.19 and 0.10) had the lowest values. Examination of subindicator values allowed the separate evaluation of different aspects of soil quality: subindicators of organic matter, aggregation and morphology and biodiversity of macrofauna had the maximum values in coffee plantations (0.89; 0.72 and 0.56, respectively on average) while eroded soils had the lowest values for these indicators (0.10; 0.31 and 0.33, respectively).Indicator formulae derived from information gained at the Nicaraguan sites were not applicable to the Colombian situation and site-specific constants were calculated.This indicator allows the evaluation of soil quality and facilitates the identification of problem areas through the individual values of each subindicator. It allows monitoring of change through time and can guide the implementation of soil restoration technologies. Although GISQ formulae computed on a set of data were only valid at a regional scale, the methodology used to create these indices can be applied everywhere. 相似文献
50.
Blume E Bischoff M Moorman TB Turco RF 《Journal of agricultural and food chemistry》2004,52(24):7382-7388
Understanding the dissipation rates of chemicals in unsaturated and saturated zones of subsurface soils will help determine if reductions of concentrations to acceptable levels will occur. Chemical properties and microbial biomass and activity were determined for the surface (0-15 cm), lower root (50-105 cm), and vadose (175-220 cm) zones in a Huntington silty clay loam (Fluventic Hapludoll) collected from an agricultural field near Piketon, OH. The rates of sorption, mineralization, and transformation (formation of bound residues and metabolites) of atrazine were determined. Microbial activity was estimated from the mineralization of (14)C-benzoate. We observed decreased levels of nutrients (total organic carbon, N, and P) and microbial biomass with depth, while activity as measured with benzoate metabolism was higher in the vadose zone than in either the surface or the root zones. Sorption coefficients (K(f)) declined from 8.17 in the surface to 3.31 in the vadose zone. Sorption was positively correlated with organic C content. Rates of atrazine mineralization and bound residues formation were, respectively, 12-2.3-fold lower in the vadose than in the surface soil. Estimated half-lives of atrazine ranged from 77 to 101 days in the surface soil, but increased to over 900 days in the subsurface soils. The decreased dissipation of atrazine with increasing depth in the profile is the result of decreased microbial activity toward atrazine, measured either as total biomass or as populations of atrazine-degrading microorganisms. The combination of reduced dissipation and low sorption indicates that there is potential for atrazine movement in the subsurface soils. 相似文献