Olive fruit cell wall: degradation of pectic polysaccharides during ripening     

Jiménez A  Rodríguez R  Fernández-Caro I  Guillén R  Fernández-Bolaños J  Heredia A 《Journal of agricultural and food chemistry》2001,49(1):409-415

Olive fruits at three stages of ripening (green, cherry, and black) have been studied. After cell wall isolation, the compositions of the cell wall and that of the phosphate-soluble polysaccharides were determined. In cell walls, decreases in arabinose, xylose, glucose, and uronic acid levels were observed, together with a slight increase in mannose on ripening. At the beginning of ripening, fragments of pectic polymers were the major constituents of the phosphate-soluble fraction, with the hemicellulosic ones increasing toward the end of the process. The molecular weight of the fragments solubilized was approximately 6 kDa. After cell wall fractionation, the pectic polysaccharides soluble in imidazole and sodium carbonate were also studied. In both fractions, between the green and cherry stages of ripening, a significant loss of homogalacturonans took place. Between the cherry and black stages of ripening, rhamnogalacturonan side chains were also released in addition to homogalacturonans. In any of the pectic fractions, changes in apparent molecular weight were quantified.  相似文献   

Antipeptide antibodies recognizing plasmin sensitive sites in bovine beta-casein sequence     

Senocq D  Dupont D  Rolet-Répécaud O  Faurie F  Levieux D 《Journal of agricultural and food chemistry》2001,49(3):1571-1577

To investigate plasmin activity in cheese, we produced antibodies to bovine beta-casein with controlled specificity, suitable as markers of the integrity of the major bonds involved in its initial breakdown. Sixteen rabbits were immunized with synthetic substitutes for six plasmin-sensitive peptides. Antisera raised to the peptides (f20-39), (f40-56), (f94-113), (f184-202), and (f193-209) recognized beta-casein in ACP-ELISA, Western-blot, and biosensor assays. Casein in vitro hydrolysis by plasmin or chymosin reduced the detection of these determinants in ACP-ELISA, in agreement with the enzymatic sensitivity of bonds included within the binding sites, or in their neighborhood. Antiserum to (f20-39) in particular allowed the specific detection of plasmin cleavage at the bond generating gamma1-CN. Antisera to C-terminus preferentially detected the cleavage by chymosin. Immunoassays using these antibodies would allow in situ monitoring of significant proteolysis events without bias originated in the secondary degradation of the released peptides.  相似文献   

Effect of mycorrhizal inoculation and soil restoration on the growth of Pinus halepensis seedlings in a semiarid soil     

A. Roldán  J. Albaladejo 《Biology and Fertility of Soils》1994,18(2):143-149

An experiment was carried out to evaluate the growth of mycorrhizal Pinus halepensis seedlings planted in a semiarid soil amended with urban refuse in southeast Spain. Three fungal species were used: Pisolithus tinctorius, Rhizopogon roseolus, and Suillus collinitus. After 8 months, inoculated seedlings grown under controlled conditions did not differ significantly from controls with regard to plant height and nutrient assimilation. Other features such as root development and stem dry weight showed that the plants grew better in the absence of mycorrhizal inoculation. The mycorrhizal seedlings and the controls were planted in three experimental plots treated with urban refuse (0, 6, and 12 Kg m^-2). After 1 year of growth under field conditions the results showed that the type of fungus inoculated significantly influenced P. halepensis development. This effect varied with the dose of urban refuse. Plant growth was encouraged by the application of refuse but only at the lowest dose. Under these conditions P. tinctorius was the most effective fungus and R. roseolus yielded poorer plant development. The highest application of urban refuse led to notably worse results and a significant decrease in seedling growth compared to controls. In the control plot (without refuse) S. collinitus was the most effective fungus in plant growth improvement. The smallest application of urban refuse had a positive effect on the assimilation of N, P, and K in seedlings inoculated with P. tinctorius and S. collinitus.  相似文献   

Usefulness of the frequency data of the fourier transform infrared spectra to evaluate the degree of oxidation of edible oils     

Guillén MD  Cabo N 《Journal of agricultural and food chemistry》1999,47(2):709-719

The oxidation process of 13 edible oil samples with different proportions of oleic, linoleic, and linolenic acyl groups has been studied using Fourier transform infrared spectroscopy. The oxidation experiments were carried out by heating the samples in a convection oven at 70 degrees C. Duplicate spectra were recorded from a film of pure oil between two disks of KBr for each sample every day during the course of the oxidation, and frequency data of each band of the spectrum were collected automatically. Changes in the values of the frequency of most of the bands of the spectra were observed. The shiftings of the frequency value of specific bands allowed one to distinguish between the different stages of the oxidation process and to establish the oxidation degree of each oil sample. This methodology could be useful to evaluate the oxidative stability of edible oils in a simple, fast, and accurate way.  相似文献   

Rapid determination of inorganic and methyl mercury in fish     

Joaquin Gutiérrez  Hugo Travieso  M. Aurora Pubillones 《Water, air, and soil pollution》1993,68(3-4):315-323

A method has been developed that uses a mixed solution of NaOH, NaCl and cysteine to digest fish. Inorganic Hg and MgHg were determined by cold vapor atomic absorption (CVAAS) using a selective reduction step with SnCl₂ and SnCL₂-solutions. Ethyl alcohol was satisfactorily used to prevent excessive foaming. Two optimum digestion procedures were established: (1) using a dry block heater at 90 °C for 1 hr and (2) overnight digestion at 25 to 30 °C. Differences between both were not significant (95%) in the range of 30 to 500 ng g^?1 Hg (II) and MeHg in fish. Reduction of the Hg signal due to matrix effects in different fish species was evaluated (95 to 60%). Oily fish, shrimp and lobsters gave the highest reduction. Internal calibration by addition of Hg standards are strongly recommended when exact determinations are needed. The detection limit obtained was near 10 ng g^?1. Signals were linear in the concentration range studied (30 to 500 ng g^?1). Accuracy of analyses was in the order of 5% or better, with a relative standard deviation of 5%. The method could be applied to other environmental matrices: hair, urine and blood, with some modifications.  相似文献   

Atomic absorption spectrophotometric determination of chromium in foods     

R Farré  M J Lagarda  R Montoro 《Journal of the Association of Official Analytical Chemists》1986,69(5):876-879

A method is reported for determination of chromium in foodstuffs. Organic matter is digested with nitric acid, followed by oxidation to Cr(VI) and extraction with methyl isobutyl ketone (MIBK) after HCl addition. Chromium determinations are performed by flame absorption spectroscopy. Absence of interferences is verified and recovery tests are performed on food samples. Quantitation limit (3.8 ng/mL), accuracy (NBS Standard Reference Material 1,573 Tomato Leaves, 4,500 +/- 500 ng/g, found 3,860 +/- 409 ng/g), and precision (CV for vegetable matrix = 9.05%, CV for animal matrix = 14.95%) of the procedure are evaluated.  相似文献   

Spatial patterns of diversity and genetic erosion of traditional cassava (<Emphasis Type="Italic">Manihot esculenta</Emphasis> Crantz) in the Peruvian Amazon: An evaluation of socio-economic and environmental indicators     

Louise Willemen  Xavier Scheldeman  Víctor Soto Cabellos  Simón Rafael Salazar  Luigi Guarino 《Genetic Resources and Crop Evolution》2007,54(7):1599-1612

This study evaluates quantitatively the suitability of the use of site-specific socio-economic and environmental data as indicators to rapidly assess patterns of diversity and genetic erosion risk in cassava. Socio-economic data as well as farmers’ estimation of genetic erosion were collected in the study area, the Ucayali region of the Peruvian Amazon, through interviews with 285 cassava farmers in 50 communities, while diversity was assessed based on agromorphological characterization of 295 cassava accessions. Using multivariate regression analyses, 50 and 45% of the variation in respectively diversity and genetic erosion estimation could be explained by a selected set of socio-economic and environmental indicators. In both regression models four out of the total of 38 variables proved to contribute significantly (at p < 0.10 level). Additionally, the study revealed that farmers are a good direct source of information on the diversity present at community level, which can contribute to the development of methodologies to assess diversity more rapidly. The results of this study are valuable for the development of models to rapidly assess diversity dynamics in large areas.  相似文献   

Controlled release of carbofuran from an alginate-bentonite formulation: water release kinetics and soil mobility   总被引：4，自引：0，他引：4  

Fernández-Pérez M  Villafranca-Sánchez M  González-Pradas E  Martinez-López F  Flores-Céspedes F 《Journal of agricultural and food chemistry》2000,48(3):938-943

The insecticide-nematicide carbofuran was incorporated in alginate-based granules to obtain controlled-release (CR) properties. The basic formulation [sodium alginate (1.61%)-carbofuran (0. 59%)-water] was modified by addition of sorbents. The effect on carbofuran release rate, caused by the incorporation of natural and acid-treated bentonite (0.5 and 1.0 M H(2)SO(4)) in alginate formulation, was studied by immersion of the granules in water under shaking. The time taken for 50% of the active ingredient to be released into water, t(50), was longer for those formulations containing natural bentonite (6.1 h) or acid-treated bentonite (9.0 and 11.7 h for 0.5 and 1.0 M H(2)SO(4) treatments, respectively) than for the preparation without bentonite (4.7 h). It appears from the results that the release of carbofuran from the various formulations is controlled by a diffusion mechanism according to the n values obtained, which were close to 0.5 in all cases. The mobility of carbofuran from alginate-based CR formulations was investigated by using soil columns packed with a clay soil (53% clay and 0.08% organic matter). Two alginate-based CR formulations containing natural bentonite or acid-treated bentonite (0.5 M H(2)SO(4)) were compared to technical grade carbofuran. The use of alginate-based CR formulations resulted in a reduction of the leached amount of carbofuran compared with the total amount of pesticide leached using the technical product (50 and 75% for CR granules containing natural and acid-treated bentonite, respectively). Alginate-bentonite CR formulations might be efficient systems for reducing carbofuran leaching in clay soils, which would reduce the risk of groundwater pollution.  相似文献   

Agriculture as a phosphorus source for eutrophication in the north-west European countries, Norway, Sweden, United Kingdom and Ireland: a review   总被引：4，自引：0，他引：4  

B. Ulén    M. Bechmann    J. Fölster    H. P. Jarvie  & H. Tunney 《Soil Use and Management》2007,23(S1):5-15

  相似文献   

Establishment of Retama sphaerocarpa L. seedlings on a degraded semiarid soil as influenced by mycorrhizal inoculation and sewage‐sludge amendment     

María del Mar Alguacil  Fuensanta Caravaca  Gisela Díaz  Purificacin Marín  Antonio Roldn 《植物养料与土壤学杂志》2004,167(5):637-644

A field experiment was carried out to evaluate the effectiveness of mycorrhizal inoculation with three arbuscular mycorrhizal (AM) fungi (Glomus intraradices Schenck & Smith, Glomus deserticola (Trappe, Bloss. & Menge), and Glomus mosseae (Nicol & Gerd.) Gerd. & Trappe) and the addition of composted sewage sludge (SS) with respect to the establishment of Retama sphaerocarpa L. seedlings, in a semiarid Mediterranean area. Associated changes in soil chemical (nutrient content and labile carbon fractions), biochemical (enzyme activities), and physical (aggregate stability) parameters were observed. Six months after planting, both the addition of composted SS and the mycorrhizal‐inoculation treatments had increased total N content, available‐P content, and aggregate stability of the soil. Values of water‐soluble C and water‐soluble carbohydrates were increased only in the mycorrhizal‐inoculation treatments. Rhizosphere soil from the mycorrhizal‐inoculation treatments had significantly higher enzyme activities (dehydrogenase, protease‐BAA, acid phosphatase, and β‐glucosidase) than the control soil. In the short‐term, mycorrhizal inoculation with AM fungi was the most effective treatment for enhancement of shoot biomass, particularly with G. mosseae (about 146% higher with respect to control plants). The addition of the composted SS alone was sufficient to restore soil structural stability but was not effective with respect to improving the performance of R. sphaerocarpa plants.  相似文献