Selective modification of clay minerals for the adsorption of herbicides widely used in olive groves

Ground and surface water contamination by herbicides applied to olive groves in Spain and other Mediterranean countries is demanding strategies to prevent and remediate the environmental problems repeatedly caused by such herbicides. In this study, six different organic cations (L-carnitine, spermine, hexadimethrine, tyramine, phenyltrimethylammonium, and hexadecyltrimethylammonium) were incorporated into Na-rich Wyoming montmorillonite (SWy-2) and Ca-rich Arizona montmorillonite (SAz-1) at two different loadings (50% and 100% of the cation exchange capacity of the clays) as a strategy to enhance the affinity of the clay minerals for three herbicides widely used in olive groves: terbuthylazine, diuron, and MCPA. The modified montmorillonites were characterized and tested as adsorbents of the herbicides through batch adsorption tests. At the experimental conditions used, some of the modified montmorillonites removed more than 95% of the herbicide initially present in aqueous solution, whereas the unmodified clays removed less than 15%. All three herbicides displayed very strong affinities for SAz-1 exchanged with hexadecyltrimethylammonium cations, particularly when these were incorporated at 100% of the cation exchange capacity of the clay mineral. Terbuthylazine and diuron also displayed very strong affinities for SWy-2 exchanged with L-carnitine and spermine, respectively. The chemical characteristics of the organic cation greatly influenced the adsorptive properties of the resultant organoclay. The herbicides were in general reversibly adsorbed by the modified clays. The results indicate that some of the tested modified clays could be suitable for the removal of the assayed herbicides from contaminated water and also as possible supports for the design of slow release formulations of such herbicides to attenuate their environmental impact when used in high-risk scenarios such as olive groves.     

A calorimetric study of thermal denaturation of recombinant human lactoferrin from rice

Thermal denaturation of recombinant human lactoferrin from transgenic rice with different degrees of iron saturation has been studied by differential scanning calorimetry. The maximum temperature, enthalpy change, and activation energy of denaturation were higher when recombinant lactoferrin was more saturated with iron, indicating an increase in the stability of the protein structure. Maximum temperature and activation energy values for apo- and holo-lactoferrins were practically identical to those reported for the same forms of lactoferrin from human milk, which indicates a similar thermal stability. However, the value of enthalpy change for denaturation of the recombinant lactoferrin was 2.5-3-fold lower than that found for the human milk protein. This finding may reflect the influence that the different glycosylation pattern may have in the relationship between lactoferrin domains. Denaturation of recombinant lactoferrin in milk was compared with denaturation in phosphate buffer, and results indicated that the protein was more heat-sensitive when treated in milk than in buffer.     

Solid foodstuff supplemented with phenolics from grape: antioxidant properties and correlation with phenolic profiles

Osmotic dehydration was assessed as an operation for supplementing a solid foodstuff (a gel was used as the model food) with grape phenolics from a concentrated red grape must to increase its antioxidant properties. The model food was processed for up to 24 h, and the osmotic pressure was adjusted by diluting the concentrated red grape must. In all conditions tested, low molecular weight phenolics (相似文献   

Static-dynamic superheated liquid extraction of hydroxytyrosol and other biophenols from alperujo (a semisolid residue of the olive oil industry)

Hydroxytyrosol and other olive biophenols (OBPs) such as tyrosol, verbascoside, apigenin-7-glucoside, and alpha-taxifolin have been extracted from alperujo by using static-dynamic superheated liquids. Multivariate methodology has been used to carry out a detailed optimization of the extraction. Under the optimal working conditions no further extraction of the target analytes was achieved after 27 min (up to 2800 and 1500 mg/kg of hydroxytyrosol and tyrosol, respectively), so complete removal of them within this interval was assumed. The extract was injected into a chromatograph-photodiode array detector assembly for individual separation-quantification. The efficacy of ethanol/water mixtures to extract OBPs from alperujo has been demonstrated and compared with that of a conventional stirring-based method. These less toxic extractant mixtures are of interest with a view to future human uses of OBPs.     

Permeability profile estimation of flavonoids and other phenolic compounds by biopartitioning micellar capillary chromatography

This paper points out the usefulness of biopartitioning micellar chromatography (BMC) using capillary columns as a high-throughput primary screening tool providing key information about the oral absorption, skin permeability, and brain-blood distribution coefficients of 15 polyphenols (6 flavones, 2 flavonols, a flavanone, 2 flavan-3-ols, 3 phenolic acids, and a phloroglucinol) in a simple and economical way. For the compounds studied, except vicenin-2, rutin, chlorogenic acid, p-hydroxycinnamic acid, and 4-hydroxybenzoic acid, maximal oral absorption (>90%) can be expected, if there are not solubility problems or metabolic processes. On the other hand, the most retained compounds in BMC, that is, 5-hydroxyflavone, flavone, and flavanone, show the highest brain-blood distribution coefficients and skin permeability coefficients.     

Dietary fiber intake in two European diets with high (copenhagen, Denmark) and low (Murcia, Spain) colorectal cancer incidence

Contradictory results have been reported in studies associating dietary fiber (DF) intake and the incidence of colorectal cancer. Most studies focused mainly on the amount of total DF, but DF is a heterogeneous complex and its components are generally ignored. The aim of this work was to compare the amount and composition of DF intake in Murcia (Spain) and Copenhagen (Denmark). Total dietary fiber intake was a 31% higher in Murcia than in Copenhagen, the ratio of insoluble DF/soluble DF being similar in the two diets. DF in Murcia contains major amounts of nonstarch polysaccharides and polyphenolic compounds, mainly derived from the high consumption of fruits and vegetables (6.7 servings). Resistant starch intake was of the same order in the two regions while resistant protein intake was higher in Murcia. The quantitative and qualitative differences in DF intake may contribute to understand the differences in colorectal cancer incidence in Mediterranean and Scandinavian areas.     

Use of sewage sludge in silvopastoral systems under Pinus radiata D. Don: soil,tree growth,and pasture production

Agroforestry Systems - Short-term production in silvopastoral systems is often limited due to inappropriate soil-fertility management. Sewage sludge fertilisation could enhance productivity of...     

Seed development of Araucaria angustifolia: plant hormones and germinability in 2 years of seeds production

New Forests - During seed development, plant hormones are involved in processes such as the accumulation of reserves, cellular activity and physiological responses. The present study aimed to...     

Thinning decreased soil respiration differently in two dryland Mediterranean forests with contrasted soil temperature and humidity regimes

The effects of a thinning treatment on soil respiration (Rs) were analysed in two dryland forest types with a Mediterranean climate in east Spain: a dry subhumid holm oak forest (Quercus ilex subsp. ballota) in La Hunde; a semiarid postfire regenerated Aleppo pine (Pinus halepensis) forest in Sierra Calderona. Two twin plots were established at each site: one was thinned and the other was the control. Rs, soil humidity and temperature were measured regularly in the field at nine points per plot distributed into three blocks along the slope for 3 years at HU and for 2 years at CA after forest treatment. Soil heterotrophic activity was measured in laboratory on soil samples obtained bimonthly from December 2012 to June 2013 at the HU site. Seasonal Rs distribution gave low values in winter, began to increase in spring before lowering as soil dried in summer. This scenario indicates that with a semiarid climate, soil respiration is controlled by both soil humidity and soil temperature. Throughout the study period, the mean Rs value in the HU C plot was 13% higher than at HU T, and was 26% higher at CA C than the corresponding CA T plot value, being the differences significantly higher in control plots during active growing periods. Soil microclimatic variables explain the biggest proportion of variability for Rs: soil temperature explained 24.1% of total variability for Rs in the dry subhumid forest; soil humidity accounted for 24.6% of total variability for Rs in the semiarid forest. As Mediterranean climates are characterised by wide interannual variability, Rs showed considerable variability over the years, which can mask the effect caused by thinning treatment.

     

Influence of diet and feeding strategy on the performance of nitrifying trickling filter,oxygen consumption and ammonia excretion of gilthead sea bream (Sparus aurata) raised in recirculating aquaculture systems

Gilthead sea bream (Sparus aurata) was raised in six individual recirculating aquaculture systems (RAS) whose biofilters’ performance was analyzed. Fish were fed with three different diets (a control diet, a fishmeal-based diet (FM), and a plant meal-based diet (VM)) and with three different feeding strategies (manual feeding to apparent satiation, automatic feeding with restricted ration, and auto-demand feeding). For every combination of diet and feeding strategy, the mean oxygen consumption, ammonia excretion, and ammonia removal rate were determined. Fish fed with the VM diet consumed the most oxygen (20.06?±?1.80 gO₂ consumed kg^?1 day^?1). There were significant differences in ammonia excretion depending on the protein content and protein efficiency of the diet, as well as depending on feeding strategy, which in turn affected ammonia removal rates. Fish fed by auto-demand feeders led to the highest mean ammonia removal rate (0.10 gN-TAN removed m^?2 biofiltration area day^?1), while not leading to peaks of high ammonia concentration in water, which preserve fish welfare and growth.