Characterization of the interaction between two food aroma components, alpha-pinene and ethyl butyrate, and ethylene-vinyl alcohol copolymer (EVOH) packaging films as a function of environmental humidity

The ethylene-vinyl alcohol copolymers (EVOHs) are well-known high oxygen barrier materials that are being used successfully in the design of packaging structures for oxygen-sensitive food or pharmaceutical products. Recently, there has been increasing interest in using EVOH materials to provide a high barrier to organic compounds as a means to reduce food aroma scalping. However, the barrier function of this family of materials diminishes significantly in humid environments, and it is supposed that so does the organic vapor barrier. In this work, a new sorption-based method to characterize the interaction between food aroma and polymer films for packaging as a function of relative humidity is presented and is used to determine the barrier to ethyl butyrate and alpha-pinene of EVOH at 23 degrees C. The results show that although EVOH is an excellent barrier to food aroma when dry, a property that even improves at low relative humidity (RH), the solubility and diffusivity of the compounds tested increase dramatically with humidity at medium to high water activities. However, even in the worst case (100% RH), EVOH outperforms low-density polyethylene (LDPE) as a barrier to organic vapors at least 500,000-fold.     

Decomposition of Gaseous Acetone in an Annular Photoreactor Coated with TiO2 Thin Film

Photocatalytic decomposition of gaseous acetone was studied with a fixed-bed annular reactor using TiO₂ as the photocatalyst. The relation of UV light intensity to the reaction rate was found to be roughly first-ordered. The decomposition of acetone was obviously enhanced with increasing retention time. Removal of acetone was slightly increased with the relative humidity for experiments conducted with relative humidity below 20%. However, the removal of acetone was decreased drastically with relative humidity for experiments conducted with relative humidity greater than 20%. Decomposition of acetone was promoted considerably with increasing oxygen concentration for experiments conducted with oxygen less than 200,000 ppmv, yet the decomposition of acetone was kept relatively constant for experiments conducted with oxygen above 200,000 ppmv. Based on the mass balance for carbon species, the amount of organic intermediates formed for experiments conducted under various conditions were found to be minimal. Experimental results for the decomposition of gaseous acetone by UV/TiO₂ process can be adequately described by the developed two-site Langmuir–Hinshelwood (L–H) kinetic model.     

亏缺灌溉与有机肥结合对夏玉米水分及产量影响

为了解减少灌水量和尿素对夏玉米产量和水分的影响。通过田间试验,以夏玉米为研究对象,选取课题组研发的有机质含量高、保水性能强的有机肥,结合2个水平的灌溉(充分灌溉W1和亏缺灌溉W2),采用等氮的原则,对有机肥与无机肥混施(F1:100%无机化肥;F2:24%有机肥+76%无机化肥;F3:48%有机肥+52%无机化肥),研究灌水量与有机无机肥对夏玉米水分利用效率和产量的影响。结果表明:与F1处理相比,在充分灌溉(W1)条件下,F2和F3处理的籽粒产量提高4.8%~6.3%;亏缺灌溉(W2)条件下,有机肥处理的籽粒产量提高1.8%~2.3%。在相同灌溉水平下,有机肥处理显著提高收获时土壤贮水量,为冬小麦发芽和生长提供一定的湿度。施有机肥处理对三叶期和小喇叭口期株高有显著影响,而对其他生育期株高影响不显著。亏缺灌溉(W2)和施有机肥(F2)的处理产量较好,是夏玉米种植管理中的一个有效方案。这种灌溉施肥管理可为关中平原及环境相似地区提供科学依据。     

水氮互作对设施菜田土壤氮素形态组成以及细菌群落结构的影响

利用室内模拟培养试验,研究了不同水氮互作条件对设施菜田土壤氮素形态组成和细菌群落结构的影响.主因素为2种土壤水分条件:70％田间持水量和100％田间持水量;副因素为5种氮素添加形态:不施氮肥、纯无机氮、纯有机氮、2/3无机氮+1/3有机氮和1/3无机氮+2/3有机氮.结果表明:水氮互作效应对土壤无机氮含量和土壤细菌群落...     

Dry Matter Loss for Hybrid Rough Rice Stored Under Reduced‐Oxygen Conditions

The objectives of this research were to characterize dry matter loss of hybrid long‐grain rough rice during storage under reduced‐oxygen conditions and develop a new approach to predict the dry matter loss by using storage temperature and relative humidity data as input. Two long‐grain hybrid rice cultivars, CL XL745 and XL760, harvested in the year 2015 were stored in rough‐rice form in sealed glass jars at moisture contents of 12.5, 16, 19, and 21%, (wet basis) and temperatures of 10, 15, 20, 27, and 40°C for a total of 16 weeks, with samples taken at 2, 4, 6, 8, 10, 12, and 16 weeks of storage. Results revealed no differences in dry matter loss connected with the rough‐rice moisture content levels and temperature during the storage duration. However, the dry matter loss was statistically different based on rough‐rice cultivar. Experimental data were fitted to a dry matter loss equation for long‐grain rice found in literature. The dry matter loss equation developed for conditions of grain storage without oxygen limitation did not accurately predict rough‐rice dry matter loss under reduced‐oxygen conditions. Equation constants generated for reduced‐oxygen storage conditions were significantly lower than the typical constants used for long‐grain rice in literature. Hence, integration of rice cultivar and storage conditions such as oxygen supply is crucial for accurate determination of kinetics of dry matter loss during storage of hybrid long‐grain rough rice.     

Fatty acid effect on hydroxypropyl methylcellulose-beeswax edible film properties and postharvest quality of coated 'Ortanique' mandarins

The objective of this work was to investigate the effect of fatty acid (FA) type and content on mechanical properties, water vapor permeability and oxygen permeability of hydroxypropyl methycellulose (HPMC)-beeswax (BW) stand-alone edible films. The effect of these films formed as coatings on the postharvest quality of 'Ortanique' mandarins was also studied. Selected FAs were stearic acid (SA), palmitic acid (PA), and oleic acid (OA), using BW/FA ratios of 1:0.5 and 1:0.2 (w/w). HPMCBW coatings reduced weight and firmness loss of 'Ortanique' mandarins, without compromising flavor quality compared to uncoated mandarins. Coatings containing OA provided the best weight loss control at both concentrations tested; however, when the BW/OA ratio was 1:0.5, the coatings increased fruit internal CO2, ethanol, and acetaldehyde contents of 'Ortanique' mandarins, therefore reducing flavor compared to the rest of the coatings studied. Although barrier and mechanical properties might be used to understand coating performance, differences observed between film oxygen permeability and coating permeability indicate that permeance should be measured on the coated fruit.     

Comparison of Analytical Methods for Organic Matter in Composts and Organic Mulches

Abstract

The conventional dichromate (Walkley and Black), carbon analyzer, and weight loss‐on‐ignition (WLOI) methods are compared for determination of organic matter contents in composts and organic mulches. The objective of this study was to evaluate these three methods for their reliability in determining the organic matter contents of composts and organic mulches that also contain inorganic carbon. The carbon analyzer method overestimated organic matter contents for samples containing inorganic carbon (C) as carbonate or charcoal C. The removal of inorganic C improved the correlation coefficients (r) of results obtained by the carbon analyzer method and the Walkley and Black method (0.95 vs. 0.89). The WLOI method produced results more similar to those obtained with the Walkley and Black method than with a carbon analyzer. Oven drying samples for 16–24 h at 105°C as a basal temperature for WLOI improved results compared with a basal temperature at 70°C, which is commonly used. A heating temperature of 500°C for 12 h resulted in organic matter determinations by the WLOI method in the closest agreement with those obtained by the Walkley and Black method.     

Influence of the physical state of water on the barrier properties of hydrophilic and hydrophobic films

Water transfer through different films, as a function of the physical state of water in contact with the film, the relative humidity difference, and the water vapor pressure difference, was investigated. The films were two synthetic packagings (hydrophobic polyethylene and hydrophilic cellophane) and an edible film. The physical state of water affects water sensitive films, such as cellophane, inducing a higher liquid water transfer due to interactions with the polymer. For hydrophobic polymers, such as polyethylene, neither the physical state of water nor the relative humidity has an influence on the water permeability. In complex system, such as an edible film composed of hydrophilic particles dispersed in a lipid phase, barrier efficiency is influenced by the continuous hydrophobic phase but could also be affected by the physical state of water due to the presence of hydrophilic compounds.     

Multivariate Statistical Techniques for the Assessment of Surface Water Quality at the Mid-Black Sea Coast of Turkey

The aim of this study was to investigate the seasonal and spatial variations in surface water quality at the mid-Black Sea coast of Turkey. The samples were collected from ten monitoring stations including rivers and sea water during the years from 2007 to 2008. The samples were analyzed for 25 parameters: total carbon, total inorganic carbon, total organic carbon, chromium, cadmium, copper, lead, iron, nickel, manganese, phenol, surfactants, ammonium, nitrite and nitrate-nitrogen, total phosphorus, adsorbable organic halogen, sulfate, hardness, dissolved oxygen, pH, temperature, total dissolved solids, electrical conductivity, and salinity. Multivariate statistical techniques, cluster analysis (CA) and factor analysis/principal component analysis (FA/PCA), were applied to analyze the similarities among the sampling sites to identify the source apportionment of pollution parameters in surface waters. The results indicate that seven factors for river water explained 82.24% of the variance. In seawater, seven factors account for 89.65% of the total variance. Varifactors obtained from factor analysis indicate that the parameters responsible for water quality variations are mainly related to organic pollution (municipal effluents), inorganic pollution (industrial effluents and waste disposal areas), nutrients (agricultural runoff), and dissolved salts (soil leaching and runoff process).     

Water Vapor Barrier Properties of Zein Films Plasticized with Oleic Acid

Water sorption, water vapor permeability, and tensile properties were evaluated for zein films plasticized with oleic acid. The effect of relative humidity on water vapor permeability and tensile properties of films was investigated. Samples were produced by two different methods: casting from a zein solution and stretching from a zein-fatty acid resin. Films were also coated with linseed oil. Results indicated that preparation method affected water sorption and permeability of zein films. Resin films showed lower water sorption than cast films, especially at high A_w values. Water vapor permeability was also lower for resin films. Coating with linseed oil further improved water vapor barrier ability of resin films. Permeability was affected by environmental relative humidity; higher relative humidity resulted in increased permeability. Environmental relative humidity also affected tensile properties of resin films. Toughness and elongation were improved when relative humidity increased from 50 to 85% rh. Tensile strength showed a maximum at 75% rh. Coating improved elongation and toughness of films. Maximum elongation and toughness were observed for coated samples at 85% rh. Zein resin films showed good tensile and water barrier properties that were maintained through environmental humidity levels from 50 to 98% rh.     

Short-term effects of organic and inorganic fertilizers on soil microbial community structure and function

A field study was carried out to analyze the short-term impacts of replacing mineral by organic fertilizers on the microbial and biochemical parameters relevant for soil fertility and crop yield. Three types of fertilization regimes were compared: (1) conventional fertilizer regime with inorganic fertilizer, and combined integrated fertilizer regimes in which 25 % of the nutrients were supplied by either (2) rabbit manure or (3) vermicompost. The effects on microbial community structure and function (phospholipid fatty acid [PLFA] profiles, bacterial growth, fungal growth, basal respiration, β-glucosidase, protease and phosphomonoesterase activities), soil biochemical properties (total C, dissolved organic carbon [DOC], N-NH₄ ⁺, N-NO₃ ^?, PO₄, total K) and crop yield were investigated in the samples collected from the experimental soil at harvest, 3 months after addition of fertilizer. The integrated fertilizer regimes stimulated microbial growth, altered the structure of soil microbial community and increased enzyme activity relative to inorganic fertilization. Bacterial growth was particularly influenced by the type of fertilizer regime supplied, while fungal growth only responded to the amount of fertilizer provided. The use of manure produced a fast increase in the abundance of PLFA biomarkers for Gram-negative bacteria as compared to inorganic fertilizer. Nutrient supply and crop yield with organic fertilizers were maintained at similar levels to those obtained with inorganic fertilizer. The effects of the organic amendments were observed even when they involved a small portion of the total amount of nutrients supplied; thereby confirming that some of the beneficial effects of integrated fertilizer strategies may occur in the short term.     

The control of aluminium solubility in some acidic Australian soils

The variation in the solubility of aluminium in some acid soils of south-eastern Australia has been investigated. The hypothesis was that leaching of silicic acid influenced the extent of clay decomposition, and hence aluminium solubility, in accord with Le Chatelier's principle. In lower rainfall areas (< 800 mm) control of Al solubility was consistent with a poorly crystalline kaolinite as the source phase, while at higher rainfall (> 1200 mm) it was consistent with gibbsite control. However, soluble silica concentrations were too high for gibbsite and kaolinite to be thermodynamically stable phases. The hypothesis was modified to take account of a quasi-equilibrium in the open soil system, in which clay dissolution and A1 solubility appear to depend on the relative rates of H⁺ input and of silica leaching. These may result in a supersaturated, or possibly even undersaturated system, at any point in time. The relative sizes of the organic sink and mineral Al source determine the influence of organic matter on Al solubility.     

Soil vulnerability to pollution in Europe

Abstract. Pollution by inorganic and organic substances is increasingly disrupting the natural functions of soils. Some soils seem capable of receiving and holding chemical compounds, at the same time retaining their ecological flexibility, but others are readily damaged and should be regarded as vulnerable to particular pollution scenarios.
At the request of the Chemical Time Bombs (CTB) Project, the International Soil Reference and Information Centre (ISRIC) organized an international workshop to assess the feasibility of increasing awareness of 'soil vulnerability' by a mapping exercise for Europe (SOVEUR), at a scale of 1:5 M, with reference to selected organic and inorganic contaminants. The workshop participants outlined procedures for a GIS-based approach to determining areas where vulnerable soils occur, and formulated proposals for the implementation phase of the SOVEUR programme. Funding is now sought for continuation of the work outlined in this paper.     

Accuracy of COD Test for Landfill Leachates

COD (chemical oxygen demand) has historically been considered to be an estimate of organic matter, and though this is no longer the case, for most kinds of water it is still a fair approximation. Landfill leachates may, however, be one of the exceptions. Landfill leachate contains many inorganic substances and, in certain circumstances, high concentrations of volatile organic compounds like acetic acid; the COD value may be affected by these conditions. Designed experiments were performed to determine how COD could be affected by the composition of landfill leachates. The factors studied include the content of iron(II), manganese(II), sulphide, ethanol, acetic acid, ammonia, and chloride as well as different aspects of the COD analysis design. The results show that up to about one-third of COD may be due to the inorganic components of leachates. The main conclusion from the experiments is that COD cannot be used solely as a measure of the organic matter of landfill leachate since inorganic substances as well as interactions between substances may interfere with the COD results.     

Characterization of diffusivity‐based oxygen transport in Arctic organic soil

Arctic terrestrial ecosystems are characterized by large deposits of near‐surface soil organic carbon in poorly drained areas. Recent changes in Arctic regions such as warming and changes in water balance have adverse effects on the dynamics of near‐surface oxygen, leading to a potential increase in oxidation of near‐surface carbon and emission of CO₂. This study investigated oxygen diffusivity characteristics, in both gaseous and liquid phases, in the upper 10 cm of an organic soil profile from a peatland in Disko, West Greenland (69°N). Two commonly used methods for calculating diffusivity of gaseous‐phase oxygen were applied and discussed to select the most appropriate method for highly porous media, for example peat soil. We measured diffusivity of gaseous‐phase oxygen with a one‐chamber diffusion set‐up in soil at different air contents (mimicking draining), and described it numerically with a previously developed parametric diffusivity model. We obtained precise measurements of liquid‐phase oxygen diffusivity along a depth profile (0–2 cm) in water‐saturated peat soil with a diffusivity microsensor coupled to a micromanipulator. The results show that the choice of an appropriate diffusivity model is critical for predicting oxygen diffusivity in organic soil and that diffusivity in mineral soil is not representative for organic soil. Furthermore, the importance of the non‐linear functionality between water saturation and diffusivity is demonstrated. This highlights the importance of measuring and modelling oxygen diffusivity rather than relying on measurements of observed water content in future studies of CO₂ and CH₄ dynamics in Arctic soil systems subject to climate changes.     

Soil phosphorus mobilization in different taxonomic orders

Changes in P fractions using Hedley's sequential fractionation of organic and inorganic soil P, were studied in soils covering a wide range of developmental stages and original materials. A greenhouse experiment was performed in order to make an exhaustive P uptake by Lolium perenne and to study soil phosphorus mobilization from different fractions. Samples were obtained at 30, 60 and 90 days from sowing, with two fertilization rates added as KH₂PO₄. The exhaustion produced by plants resulted in different patterns of mobilization according to soil characteristics. For control soils the contents of inorganic labile fraction (LIP) decreased at the end of the experience in Mollisol (31%), Vertisol (24%) and Andisol (17%). The mobilization of organic P was greater for Ultisol and Andisol (77 and 75% respectively) than for the other soils. Fertilization affected mainly inorganic P, with a significant increase in contents of LIP in Entisol (46%) and moderately resistant inorganic P (MRIP) in Andisol (15%). Inorganic P/organic P relationship tended to increase during the experiment, while labile P/moderately resistant P increased in Entisol and Mollisol.     

Analysis of metal cations and inorganic anions in olive oil mill waste waters by atomic absorption spectroscopy and ion chromatography. Detection of metals bound mainly to the organic polymeric fraction

Metal cations were quantitatively detected by atomic absorption spectrometry in samples of olive oil mill waste waters obtained by a pressure process (omww(1)) (K, 17.1; Mg, 2.72; Ca, 2.24; Na, 0.40; Fe, 0.123; Zn, 0.0630; Mn, 0.0147; Cu, 0.00860 g L(-)(1)) and a centrifugation process (omww(2)) (K, 9.80; Mg, 1.65; Ca, 1.35; Na, 0. 162; Fe, 0.0330; Zn, 0.0301; Mn, 0.00910; Cu, 0.00980 g L(-)(1)). The inorganic anions, determined in the same samples by ion chromatography, proved to be Cl(-), H(2)PO(4)(-), F(-), SO(4)(2)(-), and NO(3)(-) (1.61, 1.05, 0.66, 0.52, and 0.023 g L(-)(1), respectively, in omww(1) and 0.61, 0.40, 0.25, 0.20, and 0.0090 g L(-)(1), respectively, in omww(2)). Most of the metal cations were revealed to be bound to the omww organic polymeric fraction (opf), composed of polysaccharides, phenol polymers, and proteins. Opf relative molecular weight was substantially estimated in the range between 1000 and 30000 Da for approximately 75% and in the range from 30000 to 100000 Da for approximately 25%. The free residual cations pool proved to be neutralized by the inorganic counteranions. Finally, the possible exploitation of this material in agriculture and in environmental biotechnology processes is also discussed in the light of its chemical and biochemical oxygen demand parameters.     

Relative efficacy of organic manures on rice production in lateritic soil

Abstract. Field experiments were carried out to evaluate the relative efficacy of organic manures in improving the productivity and pest tolerance of rice growing in a lateritic soil. The effects of three commercial manures: processed city waste (PCW), vermicompost (VC) and oil cake pellets (OCP), were assessed in comparison to farmyard manure (FYM) and inorganic fertilizer all at the same total N applied. Of the organic manures tested, FYM produced the maximum straw and grain yields. Differences in yield among the organic manure treatments were mainly attributed to variation in the amounts of available N, P, K and micronutrients. Effect of manures on soil physical condition was not studied. The uptake of N, P and K by rice plants with FYM was significantly greater than all other commercial manures and inorganic fertilizer. The tolerance of rice plants to attack by pathogens and pests, measured in terms of grain yield was highest in the treatment with FYM. Among the commercial manures PCW showed the greatest promise and emerged as a potential alternative to FYM.     

有机和无机肥配比对黄褐土硝化和反硝化微生物丰度及功能的影响

【目的】 土壤硝化与反硝化作用是氮循环的两个关键环节,本文研究不同比例的有机、无机肥配施对硝化和反硝化进程产生的影响,为高效施肥提供理论基础。 【方法】 在安徽农业大学农翠园试验基地的黄褐土上进行了小麦–玉米轮作田间试验。试验以不施氮肥为对照 (CK),在小麦、玉米总施氮量相同的条件下,设置5个处理,分别为单施无机肥 (T1)、无机肥∶有机肥 = 2∶1 (T2)、无机肥∶有机肥 = 1∶1 (T3)、无机肥∶有机肥 = 1∶2 (T4)、单施有机肥 (T5)。在小麦拔节期,取0—20 cm土壤样品,利用荧光定量PCR技术测定反硝化和氨氧化微生物丰度,并结合反硝化能力、N₂O/(N₂O+N₂) 产物比、土壤呼吸、硝化势和氨氧化细菌 (AOB) 与古菌 (AOA) 对硝化势相对贡献率的测定,分析江淮地区长期有机和无机肥配施对黄褐土硝化、反硝化微生物丰度及其功能的影响。 【结果】 单施无机肥或有机肥处理的硝化势均高于不同配比处理。与添加有机肥相比,增施无机肥会显著增加AOA的丰度和硝化贡献率。在反硝化方面,反硝化能力和土壤呼吸随着有机肥投入量的增加而增加,单施有机肥处理显著高于其它处理。nirS和nosZ型反硝化菌丰度随着有机肥的增加而增加,而nirK型反硝化菌丰度呈减少趋势。相关分析表明,反硝化能力与nirS型、nosZ型反硝化菌丰度、有机质和可溶性有机碳含量极显著正相关,与nirK相关性不强。 【结论】 与单施无机肥或有机肥处理相比,有机和无机肥适当配施可降低土壤硝化势,并能调控AOA和AOB在硝化过程中的作用,有效地降低土壤反硝化损失。      

麦-稻轮作系统有机无机肥料配施协同氮素转化的机制研究Ⅱ.小麦季残留~(15)N对水稻的有效性分析

以15氮(N)标记的硫酸铵和兔粪作为无机肥和有机肥氮源,采用土培试验,研究了小麦-水稻轮作(W-R)系统小麦季残留的氮素对下茬水稻(O.sativaL.cv.Wuyujing7)生长的影响。结果表明:1)小麦季残留的氮素对水稻生长具有显著影响,有机无机肥料配施(IOF)处理的水稻籽粒产量均高于单一无机氮肥施用(IF)处理,黏壤土和黏土上分别高49.3%和14.9%;2)与IF处理相比较,IOF处理的矿质氮含量在水稻季均保持较高水平,且IOF处理显著增加了黏壤土上穗期和黏土上分蘖期、拔节期、穗期土壤矿质氮中来自于有机肥料15N和无机肥料15N的比例。IOF处理还显著增加了水稻分蘖期、拔节期、穗期土壤微生物量氮(MBN)中来自于无机肥料15N的比例;3)与IF处理相比较,IOF处理有机肥料氮促进了小麦季残留无机肥料15N在水稻生殖器官籽粒的分配比例,黏壤土和黏土上分别增加60%和52.6%,降低了其在叶片等营养器官的分配比例,降幅均在30%以上;与单一有机氮肥(OF)处理相比较,IOF处理无机肥料氮降低了残留有机肥料15N在水稻生殖器官籽粒的分配比例,黏壤土和黏土上降幅分别为20%和22.7%,增加了其在根系的分配比例,黏壤土和黏土增幅分别为90%和240%;4)与IF或OF处理相比较,IOF处理有机肥料氮促进了无机肥料15N在土壤的残留,而无机肥料氮增加了有机肥料15N在植株和土壤的回收率。有机肥料氮和无机肥料氮的协同降低了双方在水稻季向环境的损失,黏壤土和黏土上无机肥料15N损失率(NLR)分别降低17%和16%,而有机肥料15N的NLR分别降低15%和56%。IOF通过提高有机、无机肥料氮在土壤-作物系统的回收减少了肥料氮在W-R轮作系统的损失。