Initial Phase Solubilization of Normal Corn Starch by Methyl Sulfoxide (DMSO): Evidence from Scanning Electron Microscopy and Size Exclusion Chromatography

Initial structure and solubility changes of normal corn and starch granules, dispersed in varying methyl sulfoxide (DMSO) concentrations were investigated by scanning electron microscopy (SEM) and high-performance size exclusion chromatography (HPSEC). Larger granules from starches held for 6 or 15min and air dried showed increased surface etching with increasing DMSO concentration (0–70%): smaller granules showed surface peeling at 70% DMSO. At 90% DMSO, larger granules fractures into smaller pieces, while smaller granules showed full surface erosion. At 100% DMSO, large chunks eroded off both large and small granules. With 100% DMSO, a sheet-like layer formed over a mass of ruptured granules during drying, suggesting that in the absence of water, DMSO dissolves part of the granule, forming a viscous solution which may limit further DMSO granule dispersion. Granules processed with critical-point drying showed additional evidence of attack. HPSEC polymer solubility increased with DMSO concentration (0–90%). At 100% DMSO, however, there was no measured solubility. Similar solubilities for starches held at 6 or 15min (0–90% DMSO) suggest that DMSO may require an external force such as heat to facilitate polymer solubility. More amylopectin of a lower molecular weight was solubilized at 6min, while more amylose was solubilized at 15min. This suggests that granule surfaces were mostly composed of amylopectin under development, while amylose was mostly confined to amorphous regions inside the granule.     

Cell release from alginate immobilized Lactococcus lactis ssp. lactis in chitosan and alginate coated beads

The effects of chitosan and alginate coatings of alginate beads with entrapped Lactococcus lactis ssp. lactis were studied in batch and continuous fermentations. Chitosan coating reduced the final concentrations of free cells, the initial release of free cells and the rate of lactate production in milk fermented batch-wise to a final pH of 4.7 in five consecutive batch fermentations. An alternative experimental system based on continuous fermentation with controlled pH and a high dilution rate was developed to better study the phenomenon of cell release. To estimate the effects of different bead coatings on cell release, alginate beads were coated with chitosan or alginate, or sequentially with chitosan/alginate or chitosan/alginate/chitosan. Chitosan coating alone seemed to reduce the rate of cell release only in the early stages of the fermentation, while sequential coatings with chitosan and alginate showed significant reduction throughout the whole test period. To examine whether the observed effects of bead coating could be explained only by a decrease in cell activity, the ratios between the rate of cell release and the rate of lactate production were examined during the fermentations for the different beads. This ratio showed qualitatively the same behavior as direct results of volumetric cell release.     

Physico-chemical aspects of the vaailability of pesticides in soil. II. Controlled release of pesticides from granular formulations

The extent to which formulation factors control the release of a toxicant from granular formulations, under the leaching action of rain, has been investigated. Using granules prepared by an agglomeration process and containing the herbicide chlorthiamid, the rate of release can be varied by changing the filler base and by the use of different binding agents. By varying the binding agent a considerable degree of control can be exercised over the release of chlorthiamid. The release of toxicant is partly by direct leaching from the granule and partly by disintegration of the granule in water which renders the toxicant more accessible. The extent to which the release of other toxicants may be controlled in a similar way has been examined using ‘Bidrin’, fenuron, 2,4-D, chlorfenvinphos and N-tritylmorpholine. Toxicant release appeared to be governed by the filler/binding agent combination used in the granule and by the water solubility of the toxicant. Where the toxicant solubility is high, control over release is difficult to achieve but where the solubility is below 2000 ppm, a considerable control is possible.     

Food preservative content reduction by controlling sorbic acid release from a superficial coating

In the aim to reduce the total amount of preservatives added in food, edible coating is used in the present study as surface retention of active agents to maintain a local high effective preservative concentration where microorganisms are intended to contaminate and/or grow, i.e. on coating surface. A food/anti-microbial coating system with sorbic acid as the active compound, agar gel as model food and wheat gluten (WG) or beeswax (BW) film as edible coatings was studied. A mathematical model able to describe the release kinetics of the anti-microbial agents from the edible coating into food products was developed and validated. It was used for estimating the local surface concentration in sorbic acid of coated model food. This surface concentration is an essential value for predicting microorganism growth but cannot be evaluated by experiments. In the case of WG coating, the surface concentration drops below 10% of the initial value after 1 h whereas in the case of the BW coating, the surface concentration remains above 75% even after one week of contact. Simulation realized using the estimated surface concentration and a simplified equation for the growth inhibition kinetics of Saccharomyces cerevisiae were compared to microbiological efficacy assessment. The calculated amount of sorbic acid required to maintain a 0.2% surface concentration during 23 days was 100 times lower when introducing the additive in a beeswax thin layer than directly in the core of the high moisture food or in a hydrophilic film such as wheat gluten.Industrial relevanceThe methodology presented in this study based on experimental measurements and mathematical predictions is of great interest for the rational design of anti-microbial coatings and could be used in industrial applications. Edible coatings are already used in commercial practice for their barrier properties (water barrier property for example to avoid remoistening or drying of cereal-based products, gas barrier properties for the coating of fresh fruits and vegetable, etc) or for food appearance improvement (brilliance of apples for examples could be improved using polysaccharide-based film). Edible coatings have proved to be suitable as vector of preservatives such as anti-microbial or anti-oxidants. By using such retention matrices, very small amount of additives is required since the preservative is concentrated at the product surface. The benefit of using anti-microbial edible coating for consumer health is consequently non-negligible and this aspect is more and more taken into account by food manufacturers. The use of active edible coatings at an industrial scale is expected to grow, in Europe, due to the European framework regulation (EC 2004/1935) which authorizes the concept of active packaging with intentional active agents' release.The efficacy of anti-microbial edible coating could be assessed through time-consuming experimental tests. But most of the time, the couple edible matrix/active compound suitable for one applicable won't be anymore suitable for another food product and empirical tests should be undertaken once more by the food manufacturer. By using an integrated approach such as the one presented in this work, based on mathematical model for predicting additive release kinetics, numerous experiments may be avoided, since once the preservative diffusivity values in the coating and the food are known, the numerical tool could be used to optimize the initial quantity of preservative to add in the coating, to predict the food shelf life as a function of coating thickness or coating concentration in preservative, etc. The data shown in this paper concerning wheat gluten- and beeswax-based films could be also added in data bases of industrial relevance for further commercial applications.The approach used in this study could be considered as an assistant and prediction tool that should (i) optimize food preservation and (ii) help manufacturers in elaboration of new food product and packaging.     

Controlled release of sorbic acid from bacterial cellulose based mono and multilayer antimicrobial films

Biodegradable bacterial cellulose (BC) based films, incorporating sorbic acid (SA) as antimicrobial agent, have been obtained. Monolayer films, prepared using powdered BC (BCP) and poly(vinyl) alcohol (PVA), were coated with BC membrane to obtain multilayer films. Tests indicated that both SA and BCP concentration influenced sensitivity to water, release rate and antimicrobial ability of mono and multilayer films. Swelling degree, water vapour permeability and water solubility increased with SA content, but decreased with BCP addition. However in case of multilayer films, water solubility was negligible. Colour measurements indicated no degradation of SA during film preparation. The release of SA was faster when BCP concentration was higher but significantly slower, as a consequence of formed crystals dissolution, when antimicrobial concentration was increased. Furthermore, compared to the results for the monolayer films, an important decrease of SA release rate through the multilayer films was determined. The antimicrobial effect was tested against Escherichia coli K12-MG1655. The results obtained indicated that the new biocomposite films could be promising antimicrobial food packaging materials.     

Effect of Metal Cations on the Swelling and Gelatinization Behaviour of Large Wheat Starch Granules

The effect of metal cations on the swelling and gelatinization behaviour of large wheat starch granules has been studied by observing their behaviour in the presence of 24 different chlorides in aqueous solutions. With most salts, increasing concentration results in gelatinization temperatures being first raised, then depressed, and then raised again. Increasing salt concentration may also cause the initial loss of anisotropy to occur at the granule surface instead of at the hilum, and result in an apparent solution of starch rather than swollen granules. The gelatinization phenomena have been classified into three major types, and these are described in detail. It is suggested that both water and partially hydrated salts can act as gelling agents for starch granules, and that the interplay of these two agencies can explain the observed complex relation between gelatinization temperature and salt concentration.     

Studies on Rye Starch Properties and Modification. Part I: Composition and Properties of Rye Starch Granules

Rye is considered as a potential raw material for starch industry. Starting from a survey of technical procedures of isolating starches from rye-flour and -grits investigations will be reported, which were performed on pilot plant- and laboratory-isolated rye starches. The present paper deals with its granule appearance and composition. A distribution of granule size between small granules (⩽ 10 μ − 15%) and large granules (⩾ 11 … ⩽ 40 μ − 85%) is typical for the totality of the starches. Differing distributions depend on the conditions of isolation: the entity of starch containing samples resulted from the laboratory procedures under investigation. Large-granule starch preparations were isolated in the pilot plant: the centrifuge-overflow contains the small-granule fraction which is high in impurities. Granule crystallinity amounts to 16%. The crystalline component - like in wheat and triticale starches - consists predominatly of A-polymorph - with up to 9% of the B-type. The isotherms of water exchange are of the cereal type. The contents of minor constituents largely relate to the small granule fraction which assembles the majority of crude protein, pentosans and lipids, which are difficult to remove

1 Large granule samples may be produced in high purity (⩽ 0,2% crude protein)

. Lipid components in all fractions influence the results of linear chain-iodine interactions and they must be removed to proceed from apparent to absolute polysac-charide indices. The absolute amylose contents amount to ∼ 25% for large granule samples and to 20–21% for small granule samples. The average chain-length of iodine binding helical regions was determined with 220–240 AGU.     

Nanoparticle silver released into water from commercially available sock fabrics

Manufacturers of clothing articles employ nanosilver (n-Ag) as an antimicrobial agent, but the environmental impacts of n-Ag release from commercial products are unknown. The quantity and form of the nanomaterials released from consumer products should be determined to assess the environmental risks of nanotechnology. This paper investigates silver released from commercial clothing (socks) into water, and its fate in wastewater treatment plants (WWTPs). Six types of socks contained up to a maximum of 1360 microg-Ag/g-sock and leached as much as 650 microg of silver in 500 mL of distilled water. Microscopy conducted on sock material and wash water revealed the presence of silver particles from 10 to 500 nm in diameter. Physical separation and ion selective electrode (ISE) analyses suggest that both colloidal and ionic silver leach from the socks. Variable leaching rates among sock types suggests that the sock manufacturing process may control the release of silver. The adsorption of the leached silver to WWTP biomass was used to develop a model which predicts that a typical wastewater treatment facility could treat a high concentration of influent silver. However, the high silver concentration may limitthe disposal of the biosolids as agricultural fertilizer.     

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。      

Granule Sizes of Canna (Canna edulis) Starches and their Reactivity Toward Hydration,Enzyme Hydrolysis and Chemical Substitution

Small and large granule fractions were isolated from canna starch (Canna edulis, green leaf cultivar), and their morphology, physicochemical properties, susceptibility towards granular starch hydrolyzing enzymes and chemical reaction with propylene oxide were investigated. Canna starch consisted of a mixed population of large, medium and small granules; the mean of granule diameter was 47.4 μm. The small granules presented round and polygonal shapes, whereas the large granules had oval and elliptical shapes. Significant variations in digestibility of the various granules size by granular starch hydrolyzing enzymes were observed. During the first 24 h, the hydrolysis rate of small granules was higher than that of native and large granule starches. After 72 h, however, the degree of hydrolysis of small granule, large granule and native starches had reached the extent of 19.6%, 32.0% and 27.2%, respectively. The larger the granule size, the higher the MS obtained when modified with propylene oxide, which was due to the higher swelling power of the large granules. The results obtained from this study suggest that small granules had lower water and chemical affinity when compared with the bigger ones. The difference in the reactivity of small and large granules could be presumably attributed to the starch components (amylose and amylopectin) and their organization of glucan chains in ordered and/or less ordered structure of these two fractions.     

A Study of Starch Granule Size and Distribution in 29 Barley Varieties

The starch granule size and distribution has been determined on 29 different samples of barley. There is a wide range in the ratio of small to large granules which varies from a minimum of 5.5:1 to a maximum of 37:1. Small granules were separated from large granules in four varieties and the average weight of the granules determined. From these values the actual percentage of small granules in the original barley starch was determined. Small granule starch may account for from 6.2–30.6% of total starch weight in the varieties examined.     

Enhanced copper release from pipes by alternating stagnation and flow events

Traditional studies of copper release in plumbing systems assume that the water extracted from a pipe follows a plug-type flow and that the pipe surface does not interact with the bulk water under flow conditions. We characterized actual stagnation-flushing cycles in a household pipe undergoing corrosion in the presence of a microbial biofilm. The mass of copper released in 10 experiments was on average 8 times the value estimated by using the plug-flow assumption. The experimental copper release pattern was explained by an advection-diffusion model only if a high copper concentration occurs near the pipe surface after stagnation. Microscopic examination of the pipe surface showed a complex assemblage of biotic and abiotic features. X-ray diffraction analyses identified only malachite, while X-ray absorption spectroscopy also revealed cupric hydroxide and cuprite. These results indicate that the surface serves as a storage compartment of labile copper that may be released under flow conditions. Thus, the diffusive transport from the pipe surface to the bulk during stagnation is not the only control of the flux of copper to the tap water when porous reactive microstructures cover the pipe. Our results highlight the need for models that consider the interaction between the hydrodynamics, chemistry, and structure at the solid-water interface to predict the release of corrosion byproducts into drinking water.     

淀粉基化肥缓释包膜的研究

用对二甲氨基苯甲醛比色法初步研究了包膜材料对尿素的透过性，并采用电导法研究了包膜化肥在水中的养分溶出情况，实验结果表明：乙酰化淀粉复合膜材料具有一定的控制释放性能。当LSA／PVA复合膜厚度失于0．193mm时，尿素的累积透过率有明显的下降，并且随着时间的延长，累积透过率变化很小；温度对包膜化肥在水中的养分溶出率有显著影响，随着温度的升高，养分溶出率不断增大。LSA／PVA系列包膜化肥在水中浸泡一个月后累积释放速率达到93％左右。     

Production of Spherical Granule from Viscous Red Ginseng Extracts for Improving Product Fluency and Preservation and Its Physicochemical Properties

ABSTRACT:  Viscose red ginseng extracts dried and coated using fluidized bed coater may broaden their application in food processing industry and increasing the consumer acceptance. The operating conditions of fluidized bed coater were optimized for obtaining high yield and uniform spherical granule. The physicochemical properties and sensory characteristics among the concentrates, the fluidized bed dried core particle and the spherical granules of red ginseng extract were compared. The preservative properties of these materials were also analyzed. The predicted maximum yield of spherical granule was 85.42%, at a feeding rate (FR) of 111.04 mL/min, an atomization air pressure (AP) 275.30 kPa, and a product temperature (PT) of 68.53 °C. Most of ginsenosides, which were known as functional material, did not show significant changes after granulation, while the flowability and water solubility increased. Also, for a 10-mo storage at 30 °C, the spherical granule was the most stable among the materials considered. It can be concluded that the application of fluidized bed coater can be used for making the food product of viscous extracts more valuable.     

Measuring the release of organic contaminants from melting snow under controlled conditions

The release of organic contaminants from a melting snowpack may result in temporary concentration peaks in receiving water bodies and respective pulse exposure of aquatic organisms. It is thus of considerable interest to gain a mechanistic and quantitative understanding of the processes determining the dynamic behavior of organic chemicals during snowmelt. Uniformly structured and contaminated snow was produced with the help of a newly designed snow gun and exposed to predetermined temperature conditions in a temperature-controlled cold room. The dry density and liquid water content during four freeze-thaw cycles was recorded continuously at different layers within the snowpack using time domain reflectometry, providing information on meltwater production and propagation as well as snow metamorphism. Fractionated meltwater samples were filtered and the dissolved and particle phase analyzed for five polycyclic aromatic hydrocarbons (PAHs) using gas chromatography/ mass spectrometry. The distribution of the PAHs between the dissolved and particulate fractions of the meltwater was strongly related to their hydrophobicity. Particle-bound PAHs were released late during the snowmelt, whereas PAHs in the dissolved phase were released uniformly during a two day melting period. Even though conductivity measurements indicated a preferential early elution of ions in the first meltwater fractions, no such "first flush" behavior was observed for soluble PAH. The developed laboratory-based approach opens up for the first time the possibility of reproducible experiments on organic contaminant behavior in snow. Future experiments will explore, in detail, how the properties of organic chemicals, the physical and chemical properties of the snowpack, and the temperature variations before and during the time of melting interact to determine the timing of chemical release from a snowpack.     

Nitrogen release dynamics and transformation of slow release fertiliser products and their effects on tea yield and quality

BACKGROUND: Tea (Camellia sinensis (L.) O. Kuntze) is a perennial leaf harvested crop. It requires more nitrogen than most other crops and preferentially utilises NH₄⁺ to NO₃^? when both are available in the soil. It is expected that slow release fertilisers coupled with a nitrification inhibitor could improve the N use efficiency and simultaneously reduce environmental pollution. In this study, three slow release fertilisers were developed and tested: Ca? Mg phosphate coated urea with dicyandiamide (DCD) as a nitrification inhibitor and polyolefin coated urea with and without DCD. The main aim was to compare the nitrogen release dynamics and transformation of these fertilisers and their effects on tea yield and quality. RESULTS: The results showed that the coatings significantly slowed N release and kept mineral N in soils at a higher concentration for a longer time compared to uncoated urea. Polyolefin was a superior coating to Ca? Mg phosphate. DCD was an effective nitrification inhibitor and significantly reduced the ratio of nitrate to total mineral N in a highly acidic tea soil. The ¹⁵N use efficiency was 29% where uncoated fertiliser was applied and 46% where polyolefin coated fertiliser with DCD was applied. The application of slow release fertilisers increased the chlorophyll content in mature leaves and enhanced the uptake of mineral elements by tea plants. Bud sprouting, shoot growth and mature leaf longevity were significantly improved, resulting in higher biomass of tea plants. Slow release fertilisers increased the yield of shoots by 51–143% (mean, 106%) in a pot experiment and 4–14% (mean, 9%) in a field experiment compared to uncoated urea. Tea quality parameters, especially free amino acids, were also significantly increased. CONCLUSION: Slow release fertilisers, especially polyolefin coated urea with DCD could significantly increase the N use efficiency and improve tea growth. Their uses in tea fields not only improved the profit margin, but possibly reduced environmental pollution. Copyright © 2008 Society of Chemical Industry     

Changes in Starch Granule Size Distribution and Starch Gelatinization Properties During Development and Maturation of Wheat,Barley and Rye

Changes in starch granule size distribution of wheat, rye and barley during the development were followed with a Coulter Counter. Changes in starch gelatinization properties were determined by DSC-measurements. The “large granules” are laid down in the earliest stage of development and increase in size during the ripening period, even after the appearance of the “small granules”. In the mature grains the proportion of small granules is larger in wheat and rye than in barley. The gelatinization temperature is lower for the mature starch than for starch from an early stage of development. The enthalpy for the gelatinization of the starch increases during development which indicates that the structure of starch granules changes as a result of ripening. The content of amylose-lipid complexes in the starch increases during development, partly depending on the increasing proportion of “small granules”.     

The structure of starch granules in fried battered products

This work studies the structure of starch granules during different steps in the production of frozen battered squid rings, using image analysis and microscopy techniques. Frozen battered squid was prepared with four different batter formulations including wheat flour, corn flour, salt and leavening agent and subjected to pre-frying, freezing and final frying to obtain an industrial product. A control product for each of the formulations was prepared with no pre-frying and no freezing steps.The control products, regardless of their formulation, showed most starch components occluded into the starch granules, while the final products presented more leaching of starch components out of the granules. The use of corn flour as an ingredient increased the water retention capacity of the batter, resulting in higher area values for starch granules in formulations where this ingredient is used. There were significant differences between some formulations in the size and shape of the large starch granule population, but no significant differences were observed for the small granule population. As regards the preparation steps, short thermal treatments such as pre-frying mainly affected the large starch granules, which are weaker.     

Characterizing and designing polycation-clay nanocomposites as a basis for imazapyr controlled release formulations

A novel controlled release formulation (CRF) of the herbicide imazapyr (IMP) was designed to reduce its leaching,which causes soil and water contamination. The anionic herbicide IMP was bound to polydiallyldimethylammonium-chloride (PDADMAC)-montmorillonite composites. PDADMAC adsorption reached a high loading of polymer, which resulted in charge reversal of the clay and promoted IMP binding. The composites were characterized by Fourier transform infrared, zeta potential, and X-ray diffraction measurements, indicating electrostatic interactions of the polycation with the surface, polycation intercalation in the clay and suggesting a configuration as loops and tails on the surface at high loadings. IMP binding to the composites is affected by polycation loading and flocculation. Upon adding high concentrations of IMP to a composite of 0.16 g/g, we obtained high herbicide loadings (66% active ingredient). IMP release from the CRFs applied on a thin layer of soil was substantially slower than its release from the commercial formulation (Arsenal). Accordingly, soil column bioassays indicated reduced herbicide leaching (nearly 2-fold) upon applying the CRFs while maintaining good herbicidal activity. The new PDADMAC-clay formulations are promising from the environmental and weed control management points of view.