Chemical authentication of extra virgin olive oil varieties by supervised chemometric procedures.

This work has focused on discriminating extra virgin olive oils from Sabina (Lazio, Italy) by olive fruit variety (cultivar). A set of oils from five of the most widespread cultivars (Carboncella, Frantoio, Leccino, Moraiolo, and Pendolino) in this geographical area was analyzed for chemical composition using only the Official Analytical Methods, recognized for the quality control and commercial classification of this product. The obtained data set was converted into a computer-compatible format, and principal component analysis (PCA) and a method based on the Fisher F ratio were used to reduce the number of variables without a significant loss of chemical information. Then, to differentiate these samples, two supervised chemometric procedures were applied to process the experimental data: linear discriminant analysis (LDA) and artificial neural network (ANN) using the back-propagation algorithm. It was found that both of these techniques were able to generalize and correctly predict all of the samples in the test set. However, these results were obtained using 10 variables for LDA and 6 (the major fatty acid percentages, determined by a single gas chromatogram) for ANN, which, in this case, appears to provide a better prediction ability and a simpler chemical analysis. Finally, it is pointed out that, to achieve the correct authentication of all samples, the selected training set must be representative of the whole data set.     

复混肥料用重钙作磷源的技术研究

通过采用粉状重钙、粒状重钙和氨化重钙作复混肥磷源的实际应用技术研究,对推广和实用重钙提供了理论和实际依据.     

The red soils, their origin, properties, use and management in Greece

Red soils in Greece are distributed throughout the country, but they occur more frequently in the southern provinces and constitute important soil resources supporting several land utilization types. They can be grouped into two categories: the autochthonous and the allochthonous. The former soils are found on hard limestone and on basic igneous rocks in sloping mountainous or hilly landscapes. Moreover, they can be found on mica schists and gneisses in locations adjacent to marble or calcareous mica schists.Allochthonous red soils are wide-spread on late Tertiary and Pleistocene surfaces in the lowlands. Many of these deep deposits have red strata, a few decimeters to several meters thick, or red-colored and fine-textured layers interbedded with light colored deposits of marl, or conglomerates and also with thick strata enriched with calcareous concretions. They are distributed in the thermo- and meso-mediterranean bioclimatic zones. These sites have a common feature, the gently sloping terrain that ensures efficient drainage.There are some differences in chemical and physical properties and in the clay mineralogy of the two groups of Greek red soils. Palygorskite is present in some soils developed on basic rocks; the clay minerals of the allochthonous soils on Pleistocene and late Pliocene seems to be mixed with micas in significant amounts.Soil forming factors required for the formation of red soils are: (a) parent material containing iron-bearing minerals, and rich in bases, (b) slope gradients and/or water permeabilities of the bed-rock securing excessive drainage and (c) vegetation cover that does not produce high amounts of, and deeply distributed organic matter.The allochthonous red soils have likely inherited their color from their parent materials that were transported from the originally formed residual soils on hard limestone. The soils retain the red color in the thermo-mediterranean zone only on sloping terrains. The soils on these landscapes are frequently stratified.The Greek red soils belong to the great groups of: Rhodoxeralfs, Palexeralfs, Xerochrepts, Orthents. Large portions of the allochthonous soils have been desertified or have been severely degraded and their extensive exploitation is not recommended.Soil management practices applied in the allochthonous soils include erosion control, preservation of organic matter, minimum tillage, split application of nitrogen using non-acidifying fertilizers, irrigation, soil water conservation and sheltered agriculture.     

Chemical response of hardwood oligosaccharides as a statistical function of isolation protocol

Hardwoods contain a substantial amount of hemicellulose-type oligosaccharides, the chemical structures of which are typically categorized in the xylan saccharide class. The efficient and selective isolation of these hemicelluloses is regarded as one of the most critical obstacles to overcome for their eventual biomaterial and bioenergy utilization. Therefore, the objective of the current work was to perform a fundamental exploration of the function of extraction pH, temperature, and time on the final chemical properties of the extracted hemicelluloses. The extraction chemistries employed varied pH and showed that acidic conditions provided a higher extractive yield versus alkaline conditions. An alkaline environment gave higher yields than an acidic environment and also resulted in much higher lignin removal from wood, especially at high temperature. In general, control of the pH chemistry leads to a change in the carboxylic acid groups present in the extracts. When the extraction pH changed from acidic to alkaline, the total carboxylic acid group content in the hemicelluloses removed significantly increased due to more acetic acid group hydrolysis and increased lignin degradation.     

Monolithic supports for the characterization of commercial maize products based on their chromatographic profile. Application of experimental design and classification techniques

Modern analytical techniques based on the use of RP-HPLC with monolithic stationary phases and the application of experimental design and classification tools have been applied to the analysis of maize proteins. Solubilization conditions of maize proteins and separation conditions (temperature, detection wavelength, type and concentration of ion-pairing agent, and gradient) were optimized. The elution gradient was optimized by the application of experimental design techniques. The optimized method consisted of a linear binary gradient of water/acetonitrile/0.1% trifluoroacetic acid in three steps at a flow rate of 3 mL/min with a column temperature of 35 degrees C and UV detection at 280 nm. The developed method enabled the separation of maize proteins in an analysis time close to 8 min. Moreover, this is the first time that commercial maize products have been characterized by the use of multivariate classification techniques.     

Preliminary chemometric study on the use of honey as an environmental marker in Galicia (northwestern Spain)

Thirteen metal elements were determined in 40 honey samples from Galicia with different environmental origins: rural, urban, and industrial areas. The data set of the honey metallic profiles was studied with a double purpose: first, to make a preliminary evaluation of honey as an environmental indicator in Galicia with the aim of monitoring pollution and, second, to compare the different capabilities of diverse pattern recognition prediction procedures for modeling the environmental surrounding of the hive. A certain level of similarity for urban and industrial samples was obtained using principal component analysis and cluster analysis, whereas significant differences for urban and industrial honeys were found in relation to rural honey samples. Different classification rules to associate metal content of honeys with their environmental surrounding were obtained by chemometric pattern recognition procedures. In general, the classification methods developed by neural networks provided better results than the traditional pattern recognition procedures. The metal profiles of honey seem to provide sufficient information to enable categorization criteria for classifying samples according to their environmental surrounding. Thus, honey could be a potential pollution indicator for the Galician area.     

The Cerrado into-pieces: Habitat fragmentation as a function of landscape use in the savannas of central Brazil

Habitat fragmentation and land conversion by humans for agricultural purposes are constant threats to conservation of biodiversity in the Cerrado biome. These landscapes dominated by agricultural activities became dynamic mosaics, which are formed by different land uses. Thus, understanding how the properties of these mosaics affect species’ persistence is one urgent necessity. In this study, the landscape structure of the Cerrado in Goiás State, Central Brazil, was quantified by the use of fragmentation indices, analysed at the class level. The objective of this study was to assess if land use for crop production or for pasture produces different fragmentation patterns, which can result in different pressures for the Cerrado biodiversity. The study showed that landscapes dominated by crops are more fragmented than landscapes dominated by pastures. These crop-dominated landscapes also presented a smaller number of fragments that could maintain populations of threatened mammal species in Cerrado. Regions with more preserved natural areas are in the northeast of Goiás, where there are rough relief and soil unsuitable for agriculture. Our results indicate that croplands generate a landscape structure more damaging for the conservation of biodiversity in the Cerrado biome. Otherwise, they support the importance to preserve natural remnants, even in areas occupied by agriculture, mainly due to its potential to maintain ecosystem services, and suggest that landscapes dominated by pastures should have more current value for conservation, since they showed larger fragments.     

Infrared identification test for scopolamine as the hydrobromide.

The method of preparation of scopolamine hydrobromide affects the infrared (IR) spectrum of the product. A column chromatographic procedure is used to both isolate the drug from tablets and injections and form the hydrobromide salt. This yields reproducible IR spectra and thus constitutes an identity test for scopolamine hydrobromide.     

Chemical constituents in Baccharis dracunculifolia as the main botanical origin of southeastern Brazilian propolis

Previously, it was reported that one group of propolis (Group 12) was identified in southeastern Brazil, and the botanical origin of the propolis was Baccharis dracunculifolia resinous exudates. It was also observed that honeybee (Africanized Apis mellifera) mainly visited the leaf buds or unexpanded leaves of B. dracunculifolia but rarely expanded leaves. B. dracunculifolia is dioecious with male and female inflorescences, and RPHPLC of the ethanolic extracts of the respective male and female bud resinous exudates showed the same profiles. RPHPLC profiles of propolis G12 leaf buds and unexpanded and expanded leaves of B. dracunculifolia showed similarity, but unexpanded leaves quantitatively decreased in chemical constituents as compared with leaf buds. In the case of expanded leaves, all chemical constituents were severely decreased or disappeared. Artepillin C (3,5-diprenyl-4-hydroxycinnamic acid) was also identified in both propolis and resinous exudates, and both ethanolic extracts contained the highest concentrations of this compound as compared with the rest of the chemical constituents.     

Relationship between varietal amino acid profile of grapes and wine aromatic composition. Experiments with model solutions and chemometric study

Synthetic solutions containing amino acids, sugar, water, and yeast nutrients have been fermented by Saccharomyces cerevisiae, and the volatile composition of the fermented media has been analyzed by GC. Eleven amino acid compositions imitating the characteristic amino acid profile of 11 different grape varieties were tested. Significant differences in the levels of some important volatile compounds (ethanol, ethyl acetate, acetic acid, higher alcohols and some of their acetates, methionol, isobutyric acid, ethyl butyrate, and hexanoic and octanoic acids) were found. The levels of some of the volatile compounds are well correlated with the aromatic composition of wines made with grapes of the same varieties. A multiple linear regression study produced good models for most of the odorants for which the level was related to the must amino acid composition. Partial least-squares regression models confirm that amino acid composition explains a high proportion of the variance in the volatile composition and show that the relationship between both sets of variables is highly multivariate. According to the different models, the levels of some byproducts of fatty acid synthesis are related to threonine and serine, the level of beta-phenyletanol is closely related to the level of phenylalanine, and methionol is strongly correlated to the must methionine contents. The addition of selected amino acids to different musts confirms the previous observations.     

Chemical effects of pH 3 sulphuric acid on a soil profile

Cores of podzolic soil (monolith lysimeters) were treated for 4.8 yr with 1500 mm yr^?1 of either 0.5 mM H₂SO₄ at pH 3, equivalent to 24 g S m^?2 yr^?1 (acid treated) or distilled water (controls). The acid treatment was about 37 times greater than the average annual input of H₃O⁺ from rain at the site from which the monoliths were taken. Acid treatment acidified the litter (from pH(CaCl₂)3.4 to pH(CaCl₂)2.6) and the mineral soil to a depth of 80 cm (mean pH(CaCl₂) decrease of 0.2 unit). In the litter and upper A horizon, ion-exchange reactions provided the main neutralizing mechanism, resulting in a decrease in the reserves of extractable (in 2.5 % acetic acid) Ca, Mg, and Mn of about 70 to 80 %. Dissolution of solid phase Al from hydrous oxides provided most neutralization below this depth. Al3⁺ was the principal soluble Al species throughout the profile. In the litter and upper A horizon, some of the mobilized Al³⁺ was retained on cation exchange sites resulting in an increase in exchangeable Al. Deeper in the profile, where the exchange sites were effectively saturated with Al³⁺, no increase in exchangeable Al occurred, and Al³⁺ was, therefore, available for leaching. Some reversible adsorption of SO₄ ^2?, associated with hydrous Al oxides, occurred in the Bs and C horizons. The results are discussed in relation to possible effects of acid deposition over regions of Europe and N. America.     

Chemical ecology in wheat plant-pest interactions. how the use of modern techniques and a multidisciplinary approach can throw new light on a well-known phenomenon: allelopathy

A new holistic approach on research into allelopathy was launched in the FATEALLCHEM project. The project was financed by the European Commission in the 5th Framework Programme and involved agronomists, biologists, analytical chemists, organic chemists, environmental chemists, ecotoxicologists, and modelers. Benzoxazinones from wheat (Triticum aestivum L.) were the main group of compounds studied in the project. The project showed that future assessments of an extensive use of allelopathic crops must include the development of validated analytical methods, considerations of relevant concentrations, studies on soil transformation, ecotoxicological studies on individual compounds and mixtures, evaluation on human and mammal toxicity, and joint effect studies on weeds, insects, and pathogens. The project results clearly showed the relevance of optimizing the exploitation of cereal benzoxazinones. Crop rotation is a very traditional practice, which was given less importance for decades but is now regaining its importance in agricultural practice as a means of controlling weed seed banks and soilborne diseases and pests. When using cereals as catch crops and green manure, the allelopathic properties of the cereals could now be much more extensively exploited, choosing varieties with optimal production of benzoxazinones and optimizing the time of sowing in relation to the formation of bioactive metabolites.     

The use of sewage sludge as soil amendment. The need for an ecotoxicological evaluation

Background, aim, and scope  Sewage sludge use in agriculture should be limited by the presence of metals and other persistent environmental pollutants. The present study aims to contribute for the definition of a test battery of ecotoxicological assays that allows a proper ecotoxicological characterization of sludges, providing information on their potential hazard and identified “safe” application levels. Materials and methods  Three sludges from distinct sources (urban, olive-processing, and electroplating industries) were tested using avoidance and reproduction tests with earthworms (Eisenia andrei) and springtails (Folsomia candida) and plant growth tests with turnips (Brassica rapa) and oats (Avena sativa). Different soil–sludge mixture concentrations mimicking recommended/realistic field dosages were tested. Results  Only the sludge from the electroplating industry induced an avoidance response from the earthworms (EC₅₀ = 0.4 t/ha) and collembolans (no observed effect concentration (NOEC) = 15 t/ha). This sludge was the only sludge responsible for any effect on the reproductive output of the earthworms (EC₅₀ = 7.74 t/ha). Regarding collembolans, none of the sludges tested caused any significant decrease in reproduction. In higher plant tests, the two industrial sludges were toxic, causing a decrease growth in both species. The EC₂₀ values determined for B. rapa were 20.3 and 24.2 t/ha and for A. sativa 14.7 and 16.2 t/ha for sludges from olive-processing and electroplating industries, respectively. Discussion  The metal loadings of the different test sludges could partially explain the results obtained. The toxicity of the test sludge from electroplating industry observed on the tested invertebrates and plants could be explained by the high amount of total chromium from which 22.3% was in the most toxic oxidation state—Cr(VI). However, the toxicity caused by the sludge from the olive-processing industry in the test plants could be attributed to the presence of other compounds (not measured in this study) since the metal content was not high enough to induce such an effect. The absence of toxicity showed by the urban test sludge was in agreement with its low levels of metals. Conclusions  The response of the different test organisms and end points varied according to the sludge type. The urban sludge was non-toxic whereas the sludge from the electroplating industry caused a toxic effect on almost all parameters measured (avoidance behavior of both test organisms, reproduction of earthworms, and growth of both plant species). Sludge from the olive-processing industry only caused a toxic effect on growth of both plant species. By analyzing the sensitivity of the different parameters for the most toxic sludge, it was found that avoidance and reproduction were more sensitive than plant growth, whereas plant seed germination was not sensitive at all. Recommendations and perspectives  The ecotoxicological evaluation of wastes can be used as an environmental safety control of sludge use in agriculture. A tiered approach could be adopted for this purpose, incorporating avoidance tests in the first tier (screening level) and reproduction and plant growth tests in a second tier. But more evidence aiming to define the most suitable ecotoxicological test battery for specific sludges with a different contamination profile is still needed.     

Multielement composition of wines and their precursors including provenance soil and their potentialities as fingerprints of wine origin

The influence of the provenance soil and vinification process on the wine multielemental composition was investigated. For this purpose, two different vineyards from the Douro wine district, Portugal, were selected. Monovarietal grapes from a 10 year old vineyard were used to produce a red table wine, in a very modern winery. Polyvarietal grapes from a 60-70 year old vineyard were used to produce a red fortified wine, similar to Port, through a traditional vinification process. The multielement compositions (Al, As, B, Ba, Be, Ca, Cd, Co, Cr, Cs, Cu, Fe, Ga, Hf, Li, Mn, Mo, Nb, Ni, Pb, Rb, Sb, Sc, Sr, Ti, Th, Tl, U, V, W, Y, Zn, Zr, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) of soil, grape juices (prepared in the laboratory), and samples collected in the different steps of each winemaking process were measured. Inductively coupled plasma mass spectrometry was used, after suitable pretreatment of the samples (by UV irradiation for liquid samples and high-pressure microwave digestion for soil). Both vinification processes influenced the multielement composition of the wines. Most of the elements presented similar or even lower concentrations in the wine as compared to that observed in the respective grape juice, probably as a result of precipitation or coprecipitation with suspended particles during fermentation and/or wine aging. Evidence of effective contamination during grape pressing, fermentation, and/or fining of wines (depending on the element) was observed for Cd, Cr, Cu, Fe, Ni, Pb, V, and Zn in the fortified wine and Al, Cr, Fe, Ni, Pb, and V in the table wine. Nevertheless, significant correlations were obtained between the multielement composition of the wine and the respective grape juice (R = 0.997 and 0.979 for the fortified and table wines, respectively, n = 31, P < 0.01), as well as between that in the wine (median of the two studied wines) and the provenance soil (R = 0.994, n = 19, P < 0.01), for the set of elements determined in common in the different types of samples. These results are promising concerning the usefulness of the elemental patterns of both soil and wine as fingerprints of the origin of the studied wines. Nevertheless, more wines from the same and other wine districts must be studied in order to consolidate this conclusion. The multielement compositions of the studied wines were compared with those of wines of different characteristics and origins, as well as with the respective legal threshold limit values, when available. Relatively low metal levels, below their threshold limit values, were found in all cases.     

Heat-induced aggregation of beta-lactoglobulin as a function of pH.

The effect of pH in the range 6.0-8.0 on the denaturation and aggregation of beta-lactoglobulin (beta-lg) was investigated. Results were interpreted in terms of the reaction scheme for the denaturation and aggregation of beta-lg proposed by Roefs and De Kruif (Eur. J. Biochem. 1994, 226, 883-889). The rate of conversion of native beta-lg increased strongly at higher pH values, whereas the molecular mass of the aggregates decreased strongly. In the pH range 6.4-8.0 aggregates were formed mainly by intermolecular disulfide bonds, but even at pH 6.0, thiol/disulfide exchange reactions were involved, although to a lesser extent. The time course of the exposure of the thiol group in native beta-lg upon heating and the subsequent disappearance of this group through the formation of disulfide-linked aggregates was investigated by reaction with 5,5'-dithiobis(2-nitrobenzoic acid) and varied strongly with pH. These observations could be used, in combination with the reaction steps of the reaction scheme, to describe qualitatively the strongly pH-dependent isothermal calorimetry curves, measured at 65 degrees C.     

Hydrolytic enzyme activities in agricultural and forest soils. Some implications for their use as indicators of soil quality

Although a great deal of information exists about the effect of land use on soil enzyme activities, much of this is contradictory and brings into question the suitability of soil enzyme activities as indicators of how land use affects soil quality. The purpose of this study was to investigate the effect of land use on different soil biochemical properties, especially hydrolytic enzyme activities, with the aim of providing knowledge about the problems related to the use of enzymes as indicators of soil quality. The data presented derive from various studies in which a large number of soils under different types of forest or agricultural management were analysed by the same methods. All of the soil samples were characterized in terms of their main physical and chemical properties, the activity of several hydrolases, microbial biomass C and soil basal respiration. The results indicate that soil use causes a large reduction in organic matter content and that the effect on enzyme activity varies depending on the type of land use or management and the type of enzyme. Furthermore, the enzyme activities per carbon unit (specific activities) in soils affected by land use are almost always higher than in maximum quality soils (climax soils under oak vegetation or oak soils), and land use also generates greater increases in the specific activity as the C content decreases. The mechanism responsible for these increases probably involves loss of the most labile organic matter. Enzyme enrichment is not always produced to the same degree, as it varies as a function of the enzyme and the type of land use under consideration. It is concluded that the complexity of the behaviour of the soil enzymes raises doubts about the use of enzyme activities as indicators of soil degradation brought about by land use.     

The use of carbonatite rock powder as a liming agent

Carbonatite rock powder, originating from the Lillebukt Alkaline Complex at Stjernøy in northern Norway, can potentially be used as a slow‐releasing lime and potassium (K) and magnesium (Mg) fertilizer due to a high concentration of the easily weathered minerals calcite (42%) and biotite (30%). However, the enrichment of barium (Ba) and strontium (Sr) may cause an undesired uptake to plants when carbonatite is applied to agroecosystems. A pot experiment was designed to investigate the liming and fertilization effects of carbonatite and the potential mobilization of Ba and Sr compared to a dolomite lime commonly used in Norwegian agriculture. These liming agents were mixed with a sandy soil applied to different amounts of peat, and the uptake of Ba, Sr, calcium (Ca), Mg, and K by Festuca arundinácea Schreb. Kora (tall fescue) and Trifolium repens L. Milkanova (white clover) was evaluated. The liming agents were generally incapable of buffering the acidifying effect from increased applications of peat, while the plant dry mass was unaffected. Compared to pots given dolomite and soluble K, the availability of K from carbonatite to plants was equally high or higher, and no difference in the K:(Ca + Mg) ratio in plants was observed. Carbonatite was a significant source to plant Ba and Sr, and the uptake seemed to follow the Ca uptake. Addition of peat amplified the uptake of Ba, Sr, Ca, Mg, and K to plants, probably an effect of organic acid‐induced weathering of carbonatite. White clover took up Ba, Sr, and Ca more effectively than tall fescue, but the Ba and Sr concentrations in plants were relatively moderate compared to concentrations reported from field investigations.     

A comparison of molecular methods for monitoring soil nematodes and their use as biological indicators

Soil fauna, especially soil nematode communities may be used as indicators for monitoring soil biodiversity and ecological processes. A major drawback facing ecologists is the specialised taxonomic knowledge and labour intensive nature of the work required for traditional morphological identification of soil fauna. We review rapid molecular methods, including: DNA Barcoding or sequencing, PCR-DGGE, PCR-TRFLP and real-time PCR, which could enable an empirical assessment of soil nematode assemblages, in relation to their use as monitoring tools. Based on advantages of: high-throughput; ease of comparison between samples; and rapid data analysis, we argue that PCR-TRFLP is well suited to monitoring purposes.