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H. D. Heath B. T. Hofreiter A. J. Ernst W. M. Doane G. E. Hamerstrand M. I. Schulte 《Starch - St?rke》1975,27(3):76-82
Graft co- and terpolymers were prepared by free radical polymerizations of vinyl monomers onto ω-irradiated starch by a prototype commercial process. Products with graft contents of up to 46%, by weight, were obtained by grafting acrylamide and quaternary amine-containing esters of methacrylic acid to starch. The graft polymers were evaluated on a pilot fourdrinier paper machine as filler retention aids and compared with several commercial flocculants. Drainage rate increased markedly with one of the starch graft terpolymers that was cationic. Since the number of starch graft polymers prepared was limited, the results reported, although excellent, are not necessarily optimal. Further studies are needed to establish the relationships of graft content and terpolymer compositions to retention and drainage. 相似文献
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Degradation of Wheat Starch in a Single Screw Extruder: Characteristics of Extruded Starch Polymers 总被引:2,自引:0,他引:2
Wheat starch was processed in a 19 mm diameter, single screw extruder to study the physical and structural modifications that occur during extrusion cooking. Structural modification of the starch polymers was investigated using gel permeation chromatography (GPC), enzymatic digestions and dilute solution viscometry. Both the GPC and intrinsic viscosity results showed that the average molecular size significantly decreased as a result of extrusion processing. The relative amount of material excluded by Bio-Gel A150m was considerably lower for extruded samples than for unprocessed wheat starch and this size reduction of the amylopectin fraction was attributed to mechanical rupture of covalent bonds. The characterization of the structural modifications of the starch polymers is reported. 相似文献
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The grafting of acrylamide (AM) onto maize starch in aqueous medium initiated by ceric ammonium nitrate (CAN) has been studied gravimetrically under nitrogen atmosphere. The effect of concentration of monomer and initiator, polymerization time and reaction temperature has been studied in terms of efficiency of grafting (%GE) and percentage Add-on (%Add-on). The %GE was found to decrease with increase in monomer concentration, but the reverse trend was obtained on increasing the polymerization time and temperature. The maximum %GE was obtained at 45°C when polymerization was carried out for 180 min using [CAN] = 0.004 mol/L and [AM] = 0.141 mol/L in 100 mL of distilled water with 2 g of starch. These graft copolymers were characterized by IR spectroscopy and thermogravimetric analysis. The graft copolymers showed enhanced thermal stability than pure starch. Hydrogels were prepared by grafting AM onto gelatinized maize starch followed by saponification of these graft copolymers with NaOH. The maximum water absorption obtained was 170 g/g. 相似文献
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Detailed mechanistic pathways are described for starch-epichlorohydrin (ECH) reaction. The mature and extent of side reactions accompanying the cross-linking reaction as well as the influence of reaction conditions on these have been demonstrated. The influence of degree of crosslinking of starch on its various physicochemical properties such as swelling, solubility, gelatinization, viscosity, iodine complex, crystallinity and granular structure are discussed. 相似文献
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Graft copolymerization of acrylonitrile onto Sodium salt of partially carboxymethylated starch using ceric ammonium nitrate(CAN) has been carried out in the presence of triethylamine, diethylamine, ammonia and pyridine. The percentage of grafting varied with the nature and concentration of the amines. All the amines with exception of diethylamine have been found to suppress grafting. The relative reactivity of different amines towards grafting has been determined and found to follow the order: DEA > TEA > ammonia > pyridine. 相似文献
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The starch-epichlorohydrin (ECH) reaction follows second order kinetics, first order with respect to ECH as well as starch. The activation energy for the reaction is of the order of 38 kJ/mole and the temperature coefficient K323/K303 is of the order of 2. 相似文献
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Polyacrylonitrile (PAN)-containing graft copolymers of corn starch were prepared from monomer mixtures and then saponified, and dried. Incorporation of selected comonomers lead to shorter saponification times and higher yields of adsorbent products. Substitution of flour for starch gave products which had a higher absorbency than saponified starch-g-PAN. 相似文献
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Graft copolymers of starch and the vinyl monomers acrylamide (I) and acrylic acid (II) – prepared by γ-radiation induced grafting reactions – and a graft terpolymer of starch, I and II – prepared by base hydrolysis of a graft copolymer of starch and acrylonitrile (III) — have been evaluated as textile print paste thickeners. Preparation, characterization and evaluation procedures are presented together with results illustrating that starch poly (I) containing 39% poly (I) and starch poly (I, II) containing a mixture of 21% I and 37% II are effective thickeners in this application if used in combination with one another or with commercial thickeners such as algin (sodium alginate). 相似文献
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Sedimentation Field Flow Fractionation in combination with multi angle laser light scattering was applied to fully destructured potato and waxy corn starches to investigate the molecular weight and radius distributions of the starch components. In a range of radii betwen 50 and 500nm, information could be obtained about the influence of the medium conditions on the distributions. The averages of molecular weight and particle radius were found to decrease when holding the solution at a given temperature for an extended period of time (from 20min up to 60min) and when the temperature was increased (from 160°C up to 175°C). The molecular weight and radii of gyration of the dissolved starch species typically panged from 106 to 109 daltons and 50nm-500nm respectively. Changes in the distributions due to different conditions during the dissolution process where also recognized by changes in the shape of the distribution curve. Thus the applied technique gave satisfactory results in a high molecular weight region where SEC fails. 相似文献
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Gelatinization temperatures of starch and hydroxyethyl starch was determined using Differential Scanning Calorimetry (DSC), hot stage microscopy and viscography. The gelatinization temperature based on peak temperature of DSC is incorrect. Viscograph overestimates the gelatinization temperature. Hot stage microscopy based on visual observation gives the correct gelatinization temperature. DSC gives the heat of gelatinization which is helpful in estimating heat requirement during cooking of starch. Hydroxyethylation of starch reduces gelatinization temperature and heat of gelatinization for starch. 相似文献
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ABSTRACT: Different starches often coexist in food systems. Starch retrogradation is the primary reason for quality deterioration of a food system during storage. This article addresses the retrogradation behaviors of several starch mixtures containing normal rice starch (NRS). Potato starch, tapioca starch, waxy corn starch, hydroxypropylated potato starch, hydroxypropylated tapioca starch, and acetylated tapioca starch were mixed with NRS. Starch suspensions were gelatinized and the relative solid content, (S′) measured by pulsed nuclear magnetic resonance, was used to characterize the retrogradation behavior of starch systems. The retrogradation behaviors of starch mixtures can be divided into two categories according to the additive or non‐additive nature of S′, for which the concept “regional moisture content” was introduced. 相似文献
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研究了在蕨根淀粉、葛根淀粉和马铃薯淀粉中添加食盐、碳酸氢钠、蔗糖、油脂后微波加热效果、物料膨化效果的改变情况。结果表明:由于食盐、碳酸氢钠、蔗糖对淀粉糊化的影响及加热后的特性,随着添加量的增加膨化率变小,膨化过程也相对迟缓;随着糖含量的增加,产品的孔隙状态发生变化,孔隙变形、回缩,产品硬度减小,脆度增大,孔隙率渐大,色泽加深。油脂的添加,对脆度影响较大,但是对于膨化率、色泽的影响不大,添加过多时,口感变差。最佳配比是:食盐2%~4%,碳酸氢钠0.1%,蔗糖3%~6%,油脂3%~5%,并添加适量甜味剂以改善口感。 相似文献
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Tapioca and maize are the major sources of starch in India. Tapioca starch is produced in very small units which are not extensively mechanized. This quality of the starch produced is not of a high quality. Maize starch is produced in mechanized units. The liberalization of the economy and growing consumerism bode well for the starch industry in India. Growth of the starch industry would depend on developing applications for starch as well as optimizing usage to derive maximum benefits. The unique properties of maize and tapioca should be considered. 相似文献
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以玉米淀粉为原料,以柠檬酸和乙酸酐为交联剂制取交联淀粉,通过反复试验研究了不同混合酸的用量、不同混合酸比例、不同反应时间、不同反应温度条件对交联淀粉交联效果的影响,最后采用正交试验优化了制备交联淀粉的工艺条件,为制备交联淀粉提出了新工艺。 相似文献
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Graft co- and terpolymers of starch and the vinyl monomers acrylamide (I), acrylic acid (II), acrylonitrile (III) and β-methacryloyloxyethyltrimethylammonium monomethyl sulfate (IV) were prepared and evaluated as flocculants for bauxite ore red mud suspensions. Starch-poly (III) was base hydrolyzed to starch poly (I, II) before evaluation. Products containing poly (I), (II), and (IV) were prepared by γ-radiation induced grafting while that containing poly (III) was prepared by ceric (Ce+14) ion initiated grafting. Preparation, characterization and evaluation procedures are presented together with results illustrating that starch poly (II) containing 38% poly (II) is an effective flocculant for domestic bauxite ore red mud suspensions. 相似文献
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变性淀粉让软糖口感更佳 总被引:1,自引:0,他引:1
<正>淀粉是一种供应稳定、价格低廉,广泛应用于食品工业的重要原材料。经过或长或短的改性过程,淀粉可以转变为多种衍生物,如变性淀粉。目前变性淀粉作为一种常用的食品添加剂,已经在乳制品、酱类、冷冻食品和糖果等食品中得到了广泛地应用,其中在凝胶糖果中变性淀粉的作用尤为明显。 相似文献