Search for the contamination source of butyltin compounds in wine: agglomerated cork stoppers

A possible butyltin contamination source in wine was studied in this paper. Agglomerated cork stoppers, which were produced in Portugal, Spain, and Italy, used in wine bottles were examined. The domestic cork products, cork granules, and mucus used for cork products were also analyzed. The levels of mono- and dibutyltin compounds in corks were found in the range from <0.0024 to 3.3 and from <0.0029 to 6.7 microg of Sn/g, respectively. A low level of tributyltin contamination was also found in 2 of 31 tested samples. The presence of butyltin compounds in agglomerated cork stoppers was confirmed by GC-MS. Experimental results indicated that all overseas agglomerated cork stoppers studied contained mono- and/or dibutyltins. Butyltins were not detected in cork granules, mucus, most of the natural cork stoppers, and domestic agglomerated cork products. The concentrations of mono- and dibutyltins increased with the time in a 30-day experiment, showing that butyltin compounds can leach from agglomerated cork to the wine. When the butyltin concentrations in wine samples were compared with their levels in the corresponding agglomerated cork stoppers, a correlation was found. The potential harm of such food contamination was evaluated by the toxic research of butyltin compounds using Daphnia sp. as the experimental model.     

种植密度对沿淮玉米籽粒淀粉粒度分布与糊化特性的影响

分析不同种植密度对沿淮玉米籽粒中淀粉粒度分布与糊化特性的影响。以豫单132、京科968等13个玉米杂交品种为材料,设置56 250 株/hm2、67 500 株/hm2、77 250 株/hm2等3个种植密度,分析不同种植密度对玉米籽粒品质、淀粉粒度分布与糊化特性的影响。结果表明,在种植密度56 250~77 250 株/hm2范围内,随着种植密度的增加,玉米籽粒的蛋白质和脂肪含量呈递减趋势,淀粉含量呈递增趋势,即淀粉/蛋白质比率增加。玉米籽粒大型淀粉粒体积和表面积百分比显著增加,小型淀粉粒却显著降低。增加种植密度后玉米淀粉的峰值黏度、低谷黏度、最终黏度和稀懈值等黏度参数均呈显著升高。相关分析表明,玉米籽粒峰值黏度等黏度参数与小、大型淀粉粒体积百分比呈正相关,与中型淀粉粒体积百分比呈显著或极显著负相关。说明种植密度影响玉米籽粒淀粉粒度分布、淀粉黏度参数和组分含量。     

Effects of alfalfa particle size and specific gravity on chewing activity, digestibility, and performance of Holstein dairy cows

Two experiments were carried out to test the effects of alfalfa particle size and functional specific gravity (FSG) on chewing activity, digestibility, rumen kinetics, and production of lactating dairy cows fed corn silage based rations. In experiment 1, water-holding capacity (WHC), insoluble dry matter, hydration rate, and FSG changes were determined in alfalfa hay (varying in particle size) and corn silage. Reduction of particle size increased bulk density, FSG, and the rate of hydration, and decreased WHC of alfalfa. In experiment 2, 9 midlactation Holstein dairy cows fed total mixed rations containing 3 sizes of alfalfa hay (with geometric mean 7.83, 4.04, and 1.14 mm) were used in a replicated 3 x 3 Latin square design. The diets contained 20, 20, 35, 7, 7.5, 10, 0.3, 0.1, and 0.1% of DM alfalfa, corn silage, barley, soybean meal, beet pulp, wheat bran, dicalcium phosphate, vitamin premix, and salt, respectively. The geometric means (GM) of rations were 3.34, 2.47, and 1.66 mm in long, medium, and fine alfalfa treatments, respectively. Reduction of particle size increased daily NDF intake (kg), but decreased the proportion of physically effective factor (pef) and physically effective NDF (peNDF) in the ingested rations. Reduction of particle size increased the FSG of rations and intake of DM but reduced digestibility of NDF and ash. Reduction of particle size decreased ruminal mean retention time (RMRT), but increased the ruminal particulate passage rate. Milk and FCM yield were not affected by treatments. The rumen pH, total chewing activity, rumination, eating time, and milk fat were reduced as particle size decreased, but milk protein increased. This study showed that reduction of forage particle size increased bulk density, FSG, and hydration rate of alfalfa and was the most influential factor affecting DMI, milk composition, and chewing behavior. Reduction of forage particle size had minimal impact on digestibility and milk production.     

Dynamic mechanical analysis and creep-recovery behavior of agglomerated cork

The mechanical behavior of agglomerated cork, made of cork granules bound with polyurethane moisture-cured adhesive is investigated and compared to natural cork in the small strain regime (strain?<5%). Dynamic mechanical analysis (DMA) of the agglomerated material revealed two distinct thermal transitions, one at ?45?°C, related to the glass transition of polyurethane, and one at 3?°C, associated with melting of suberin, a natural polyester that is the main component of cork’s cell walls. Natural cork showed the latter transition to occur at a higher temperature range, between 10 and 25?°C, probably due to a different crystalline arrangement being formed upon cooling the cork granules under pressure in the mold. The storage modulus of agglomerated cork was found to be similar to that of natural cork. Creep and recovery experiments were well described by Burgers model and Weibull distribution function, respectively. Agglomerated cork showed higher instantaneous creep strain and viscous flow than natural cork, probably due to relative displacement and slippage of the granules being allowed by the binder. In all cork materials, not all the instantaneous creep strain was instantaneously recovered. A fraction underwent delayed recovery and another turned into permanent strain. This behavior was associated with the deformation of corrugations in the cork cell walls. Cyclic creep-recovery tests showed for all cork materials recoveries above 90%, except for the first cycle.     

桉木纤维水泥板的制备

测定了桉木纸浆纤维形态,探讨了桉木纤维与水泥的相适性,采用半干法制备桉木纤维水泥板。研究结果表明：桉木纸浆纤维的平均长度为2.8mm,属于长纤维;桉木纤维对水泥的阻凝作用较小,与水泥有较好的相适性,可直接用于制备水泥纤维板;木灰比和水灰比对板材的性能具有显著的影响,当木灰比为0.22、水灰比为0.42、目标密度为1.3g/cm3时,压制出的纤维水泥板静曲强度可达14MPa,弹性模量可达3900MPa,24h吸水厚度膨胀率为1.26%,均达到了水泥刨花板标准（GB/T 24312-2009）优等品的要求。     

Fractionation of Wheat Starch on the Basis of Hydrated Density

From two bread wheat cultivars having contrasted pasting properties, hydrated starch granules were separated into two fractions by flotation. These fractions were indistinguishable on the basis of granule size but were distinguished by their amylose contents and hot-pasting peak heights. Fractionation could not be obtained on dry starch, nor on wet starch from which water had been expelled by centrifugation in solvent of high density. This suggests that all sizes of granules of both cultivars could be reduced to the same level of hydration of 42% dry starch basis. The range of hydrated density was 1.305 - 1.315 g/cm³ which suggests differences between the fractions of only 4% water. Two models are developed to explain the mechanism of fractionation and the differences found between cultivars.     

微射流处理对豆乳粉溶解特性的影响

以传统湿法工艺技术制备豆乳粉为基础,为改善豆乳粉溶解性对豆浆进行微射流处理。研究不同微射流压力(0、42.5、89.0、123.5、152.0 MPa)对豆乳粉溶解特性(粒径、可溶性固形物含量、蛋白分散指数、休止角、溶解度、分散性和水合能力)的影响。结果表明:随微射流压力不断增大,豆乳粉平均粒径呈现出先下降后略有增加的趋势;可溶性固形物含量、蛋白分散指数、休止角、溶解度、分散性和水合能力呈现出先升高后降低的趋势;豆乳粉的微观结构表现为颗粒减小、趋向于均匀且分散性增加。当微射流压力为123.5 MPa时,豆乳粉具有较高的蛋白分散指数和水合能力,分别为97.35%和1.94 mL/g,豆乳粉的堆积密度较高,与对照组相比增加了25.81%。研究表明,当微射流压力为123.5 MPa时,豆乳粉具有良好的溶解特性。     

Variation of cork quality for wine stoppers across the production regions in Portugal

Cork production and technological quality were characterized following a field sampling covering the whole area of cork oaks in Portugal (six regions), with one site per 20,000 ha of cork oak area (30 sites), using samples taken from the tree at the time of cork stripping (20 trees per site). The following quality parameters were determined: thickness of the raw cork planks, calliper of the cork planks after boiling, cork growth index, i.e., growth of the first 8 complete years, density and porosity. The cork growth index was 28.6 mm, with significant differences between regions and sites within regions. A production cycle of 9 years was applied to 51% of the trees with annual productivity of 0.93 kg m^?2 year^?1 of debarked surface, 30.3 mm raw cork plank thickness, 33.9 mm corkboard calliper, 251 kg m^?3 density and a porosity coefficient of 5.8%. For all the cork quality parameters analysed, the regions and sites within regions were a significant factor of variation. This research covers the natural variability of cork production features for industrial processing, namely for the production of wine stoppers. It is the most extensive work characterizing the geographical variation of cork as an industrial raw-material. The results are useful for optimizing the production cycle and for improving management practices and regulations.     

辅酶Q10纳米脂质体配方与工艺优化研究

采用乙醇注入-超声法制备辅酶Q10纳米脂质体,以包封率、保留率、平均粒径以及平均粒径的变化程度作为响应指标,应用正交试验法优选辅酶Q10纳米脂质体的配方和制备工艺。最佳配方为磷脂:胆固醇:吐温80:辅酶Q10=2.5:0.4:1.8:1.2(W/W),水相为0.01mol/L磷酸盐缓冲液(pH7.4);最佳制备工艺条件为乙醇用量1ml,搅拌时间10min,水化温度45℃,超声功率450W。以优化配方和工艺制得的脂质体形态均匀,粒径分布范围在20～300nm之间,平均粒径为68nm,包封率高于95%,4℃下贮存四个月,粒径分布无显著变化,平均粒径的变化程度小于10%,保留率高于90%。经优化得到的辅酶Q10纳米脂质体配方合理、工艺简便可行、包封率高、稳定性好。     

Milling of rice grains: The roles of starch structures in the solubility and swelling properties of rice flour

Rice flours with different particle sizes and degrees of damaged starch granules were produced by hammer milling and cryogenic milling of rice grains, where degradation of starch molecules was evident in the hammer‐milled flours, but not in the cryogenically milled flours. The solubility and swelling properties of the resulting rice flours were determined in cold (30°C) and hot water (90°C). The cold‐ and hot‐water starch solubility was strongly correlated with the degree of damaged starch granules, and weakly with the particle size of rice flour. No evident correlations were observed between starch solubility and the molecular structures, indicating that molecular degradation by milling process was not the only precondition of increased starch solubility. Possible mechanism for the observed correlations is that increasing surface area and/or exposure of loosely packed inner part of starch granules with increasing degree of damaged starch granules allowed more starch molecules to leach out in cold and hot water. Furthermore, the cold‐water swelling of rice flour was strongly correlated with the degree of damaged starch granules, possibly due to the rapid hydration of damaged starch granules, whereas the hot‐water swelling did not show any correlations with flour particle size and granular and molecular starch structures. The results have provided better insights in the relationship between starch structures and solubility and swelling properties of rice flour, which can be used to improve the manufacture and selection criteria of rice flour for better products.     

Source apportionment and spatial distributions of coarse particles during the Regional Air Pollution Study

To identify the coarse particle sources and to estimate the variability in their contributions to coarse particle mass (CPM) concentrations across the St. Louis metropolitan area, positive matrix factorization (PMF) was applied to historic ambient coarse particle compositional data from 10 Regional Air Pollution Study/Regional Air Monitoring System (RAPS/RAMS) monitoring sites in St. Louis. Coarse particles in this study had aerodynamic sizes between 2.4 and 20 microm. The sources were qualitatively identified, and the source contributions were quantitatively estimated. Nine sources were identified for 8 of the 10 sampling sites (except rural sites 122 and 124) including soil, cement kiln/quarry, iron and steel, motor vehicle, incinerator, pigment plant primary/secondary lead smelter, zinc smelter, and copper production, respectively. At site 122, five sources were identified as soil, cement kiln/quarry, motor vehicle, incinerator, and zinc smelter. At site 124, six sources were identified as soil, cement kiln/quarry, motor vehicle, incinerator, primary/secondary lead smelter, and zinc smelter. Soil was the largest coarse particle source across the study area (6.15 microg/m3, 29.3%). Cement kiln/quarry, iron and steel, and motorvehicle sources were the other large contributions to the coarse particles mass (5.27 microg/m3, 25.1%; 3.53 microg/m3, 16.8%; 2.72 microg/m3, 12.9%). The results of this study suggest there can be significant potential for exposure misclassification in time-series epidemiologic studies when regressing health outcomes against source contributions if they were to be estimated at a single central monitoring site.     

Effect of quality, porosity and density on the compression properties of cork

The compression properties of cork were studied on samples obtained from cork planks of two commercial quality classes (good and poor quality), with densities ranging from 0.12–0.20g?cm^-3 and porosities from 0.5 to 22.0%. The stress-strain curves were characterized by an elastic region up to approximately 5% strain, followed by a large plateau up to 60% strain caused by the progressive buckling of cell walls, and a steep stress increase for higher strains corresponding to cell collapse. The direction of compression was a highly significant factor of variation, with cork showing higher strength for the radial compression. Density influenced compression and cork samples with higher density showed overall larger resistance to compression in the three directions. In the elastic region, an exponential model of Young’s modulus in function of cork density could be adjusted. The effect of porosity on compression was small and the stress-strain curves were similar regardless of the porosity of the samples, although there was a trend toward an overall increase of stress with porosity for higher strains. Porosity was characterised by a high variability in the anatomical features of the lenticular filling material and the presence of collapsed and thick walled lignified cells. The inclusion of a porosity parameter for the modelling of the elastic modulus did not improve the prediction obtained with density-based models. There was no significant difference in the compression properties of cork samples obtained from cork planks of good and poor quality classes.     

Dietary fiber from coconut residue: effects of different treatments and particle size on the hydration properties

The present work is aimed at the production of dietary fiber from underutilized coconut residue left after the extraction of milk, by subjecting it to physical treatments such as water washing, hot water washing, boiling water washing and pressure cooking, as well as solvent extraction. The fat content was reduced from 62% to 45% and 41% by treatment with boiling water and pressure-cooking, respectively. Water-holding, water retention and swelling capacities increased with decreasing fat content. A marked increase was observed in hydration properties when the fat content decreased from 10 to 2%. The hydration properties were maximum for 550 m particle size coconut fiber. For the higher particle size (1,127 m), the oil was trapped inside the fiber matrix, resulting in decreased hydration properties, whereas for the lower particle size (390 m) the rupture of the fiber matrix was responsible for low hydration properties. An attempt was made to compare the hydration properties of coconut dietary fiber with other commercially available dietary fibers.     

Effects of High Pressure Disintegration of Steeped Maize Grits on the Release of Starch Granules from the Protein Matrix

The horny endosperm of maize gives the greatest resistance to the mechanical disintegration of the protein matrix during starch extraction. Thus attempts were made to release the starch by wet-milling of maize grits in the valve of a high-pressure homogenizer. At the same time, information was gathered on the principles involved in the structural breakdown of the endosperm components. For this purpose the influence of the valve geometry as well as the concentration and flow rate of the suspension on the particle size reduction and disintegration was examined. Using a valve specially constructed for the photographic documentation of this process step, it could be shown that the slit height of the valve predominantly determined the particle size of the wet milled product. Already after a single passage through the valve, set at slit heights between 200 and 600 μm, 70% of the grits were reduced to particles <40 μm. The grits were initially between 250 and 1000 μm in size. Scanning electron microscope photographs showed that a large fraction of the mass existed as free starch granules alongside partly intact particles of the protein matrix. Since the starch granules were of higher purity after raffination, it is assumed that the extent to which disintegration of the endosperm particles results in starch granules and protein particles as separate entities, depends not only on the particle size reduction step, but also on the different visco-elastic behaviour of the protein matrix and the starch granules under the influence of the large shear forces occuring in the valve.     

二硫代焦磷酸酯水性分散体系的制备及其在阻燃粘胶纤维中的应用

针对二硫代焦磷酸酯(DDPS)阻燃剂粒径大,与粘胶纤维(VF)界面相容性差等问题,以聚氧乙烯醚型非离子表面活性剂为分散剂,通过超细加工制备了DDPS水性分散体系;探究了分散剂结构对DDPS粒径的影响,通过响应面试验方法优化超细化工艺参数;然后将DDPS水性分散体系共混添加到粘胶纺丝原液中,通过湿法纺丝制得阻燃粘胶纤维,探究了纤维的阻燃性能。结果表明:牛酯胺聚氧乙烯醚(TA10)和蓖麻油聚氧乙烯醚(EL90)复配对DDPS具有较好的协同分散作用;当研磨时间为4 h,研磨转速为1 700 r/min,分散剂TA10和EL90质量比为1.2:1时,DDPS分散体系粒径中值为0.310 μm;DDPS在阻燃粘胶原液中分布均匀,且不影响粘胶原液的可纺性;与VF相比,当DDPS质量分数为20%时,阻燃粘胶纤维热释放速率峰值下降了18.8%,极限氧指数从19%升高到31.31%。     

Roselle (<Emphasis Type="Italic">Hibiscus sabdariffa</Emphasis>) by-product as functional ingredient: effect of thermal processing and particle size reduction on bioactive constituents and functional,morphological, and structural properties

Food industry is in the search of new functional ingredients, so this study was focused on evaluating the effect of thermal processing used to produce roselle beverages, and the effect of particle size reduction, on the retention of bioactive constituents, and physicochemical, functional, and structural properties of Hibiscus sabdariffa calyces. After decoction process (DP), by-products retained up to 56% of polyphenolic compounds, 54% of flavonoids and 44% of anthocyanins; mainly delphinidin 3,5-O-diglucoside (74.1%); besides presenting an increased content of total dietary fiber (DF) as compared to roselle calyces (26%). Viscosity and hydration properties were improved by the DP, which may be related to an increased porosity as observed in the SEM micrographs. Fourier transform infrared spectroscopy spectrum, reflected the differences in the chemical composition of BP and calyx, whereas the X-ray diffraction analysis showed no effect of DP. Interestingly, samples with a large particle size (250–177 µm) presented increased viscosity, which was the most important change for particle size. Therefore, roselle beverage by-product could be a functional ingredient since is an excellent source of phenolic compounds and dietary fiber with improved functional and physicochemical properties as compared to calyces.     

Hydration and physicochemical properties of small‐particle cassava starch

Acid hydrolysis followed by ball milling was applied to cassava starch in order to fracture the granules. Lintnerisation led to degradation first in the amorphous domains and increased the crystallinity. The resulting increase in internal defects and brittleness made the granules more susceptible to breakage upon milling. Ball milling, although leading to some degree of crystallinity loss, could effectively reduce the size of acid‐hydrolysed starch while the total double helix remained relatively unchanged. The resulting small‐particle starch was structurally more heterogeneous (wider T_m range). Swelling of small‐particle starch was accompanied by solubilisation of water‐soluble fragments at a temperature greater than 60 °C. The properties of individual granules are strongly influenced by the hydration and physicochemical properties of their amorphous and crystalline domains. © 2002 Society of Chemical Industry     

Rheological characterization of edible films made from collagen colloidal particle suspensions

A rheological characterization of collagen edible films is proposed through the experimental evaluation of shear elastic modulus, toughness, hydration capability and stress and stretch ratio at fracture. These properties are obtained from hydration, simple extension and compression tests and analyzed through the BST (Blatz, Sharda, & Tschoegl, 1974) hyperelastic model. Also precursor collagen particle suspensions, with solid concentrations in the range 0.5–4% w/w, are studied to evaluate their thixotropic responses in sudden imposed shear rates and shear loops. These responses are a consequence of particle aggregations leading to cluster formations. The particle size distribution function of suspensions is determined via scanning electron microscopy. Films are formed by casting and then fixed through either a coagulation process with a salt solution or a chemical process involving covalent cross-links with glutaraldehyde. Results indicate that these collagen films behave as colloidal particulate networks composed of particles and clusters. Also it is found that the fractal dimension of clusters is an intrinsic property of collagen particle suspensions, independently from the maturation time. Clusters in these suspensions are formed with a rather open architecture (low fractal value) due to rather large particle attractive forces. The evaluation of the BST rheological parameters allows one the estimation of the energy amount required to get film fracture for different collagen and cross-linker concentrations. Since the final films have to satisfy several quality requirements before using, the interplay between their stiffness and toughness is presented and discussed.     

Effect of chemical and physical properties of Dried Distillers Grains with solubles (DDGS) on Tribolium castaneum (Herbst) development

Dried Distillers Grains with Solubles (DDGS) has been used as a grain-based supplement in animal feed. The focus of this study was to investigate the effects of chemical and physical characteristics that may affect DDGS susceptibility to Tribolium castaneum (Herbst) infestation. Multiple regression-based models were built to determine if the diet’s chemical and physical characteristics affect T. castaneum development. Based on the regression models, diet particle size was the most influential factor in larval development. Larval weight increased more rapidly on T. castaneum normal laboratory diet, 90% flour/10% brewer’s yeast (F/Y), followed by ground DDGS, compared to raw DDGS with different particle sizes. To determine the effect of diet particle size on larval development, experiments were conducted to increase particle size by pelletizing F/Y using a rotary drum granulation apparatus. T. castaneum larval stage lasted significantly longer on F/Y granules with a particle size of 1.4 mm or larger. Although the chemical properties of DDGS (protein, fat, fiber and ash content) were not significant predictors of T. castaneum larval development, larval developmental time and weight gain on ground DDGS was significantly slower than on F/Y, highlighting the potential importance of nutritional factors not accounted for in our analysis. Our results conclude that storing DDGS as raw ingredient and in the granule or pellet form with large particle size may help limit T. castaneum infestations. Although granulation or pelletization may not be economically feasible for small manufacturing plants, larger producers may benefit from the reduced risk of insect contamination associated with secondary feeders such as T. castaneum.     

甘油与丙二醇复配比例对烟草颗粒热解和释烟特性的影响

为考察雾化剂种类和质量分数对烟草颗粒热解和烟气释放特性的影响规律，采用湿法造粒技术，利用热重-红外光谱联用系统（TG-FTIR）、锥型量热仪（CONE）以及稳态热解装置与撞击采样器联用系统，研究甘油与丙二醇复配比例对烟草颗粒热解与烟气释放特性的影响。结果表明:①随丙二醇量的增加，烟草颗粒起始失重速率明显增大，总失重比例增加，主要失重温区向低温区移动，且单一雾化剂制备的烟草颗粒主要失重温区范围较小，混合雾化剂则较为宽泛；有氧裂解阶段失重速率与甘油质量分数成反比。②红外光谱分析结果显示，添加丙二醇后，烟草颗粒在100 ℃即开始释放雾化剂；随丙二醇质量分数的增加，碳水化合物、酚类、有机酸类、烟碱等胺类化合物以及烷烃、烯烃等化合物的释放量变化趋势由先增大后减小变为逐渐增大；在有氧裂解阶段，单一甘油体系裂解的气相产物以CO₂、H₂O、CO和羰基化合物为主，随丙二醇质量分数的增加，碳氢和羰基化合物的特征吸收峰增强，且CO和CO₂的特征吸收峰强度在350、400 ℃时明显增大，说明烟草裂解更为剧烈。③随丙二醇质量分数的增加，烟草颗粒的释烟时间范围减少，累积释烟总量降低，由30%（质量分数）丙二醇制备的烟草颗粒的起始释烟速率最小；增加甘油质量分数，烟草颗粒热解释放CO和CO₂的速率减小。④随甘油质量分数的增加，气溶胶总质量呈增加趋势，平均粒径则呈先减小后增大的趋势。