Gamma Radiolysis of Starches Derived from Different Foodstuffs. Part III. Study of Induced Hydrogen Peroxide

The foodstuff from which the studied starches (maize, waxymaize, amylomaize, manioc, bread-wheat, potato, rice and haricot bean) derive has only a little influence upon the quantities of gamma radioinduced hydrogen peroxide.     

Gamma Radiolysis of Starches Derived from Different Foodstuffs. Part IV. Study of Radiodepolymerization

The foodstuffs from which the investigated starches (maize, waxymaize, amylomaize, manioc, bread-wheat, potatoe, rice and haricot bean) derive has only little influence upon their radiodepolymerization, as previously stated by theory.     

Gamma Radiolysis of Starches Derived from Different Foodstuffs. Part 1. Study of Some Induced Carbonyl Derivatives

The foodstuff from which the studied starches (maize, amylomaize, waxymaize, bread-wheat, manioc, rice, potato, haricot bean) derive only has a little influence upon the quantities of gamma radioinduced carbonyl derivates: the ratio between the maximal and minimal values found is always lower than 5; the radio-induced quantities in maize starch do not vary for more than 30% around the average value found for the different starches; the different curves drawn – showing the influence of irradiation dose, atmosphere, water content – have similar shapes.     

Detection of Corn Starch Irradiated with Low Doses of Gamma Rays. Part II. Disappearance of Malonaldehyde from Starches of Various Moisture Contents

Using the thiobarbituric acid test for malonaldehyde, irradiated starch can be detected qualitatively for up to a year after irradiation. If the moisture content of the starch is known, the dose can be determined quantitatively, if below 75 krad, for up to four months after irradiation, and doses between 75 and 200 krad can be determined up to four weeks after irradiation. Decreasing production of malonaldehyde with increased moisture content is ascribed to preferential radilysis of the water rather than the starch, with formation of hydrogen peroxide. A possible route for the disappearance of malonaldehyde by reaction with hydrogen peroxide is suggested.     

几种不同品种淀粉及羟丙基产物糊液性质比较研究

以薯类淀粉(木薯,马铃薯)及禾谷类淀粉(普通玉米、蜡质玉米、高直链玉米及糯米)为原料,以环氧丙烷为醚化剂。制备了羟丙基变性淀粉。反应条件:淀粉乳质量分数40%、反应温度40℃、无水Na_2SO_4添加量12%(以淀粉干基计)、NaOH添加量1.2%、环氧丙烷添加量12%、反应时间18h。分别对原淀粉及在相同的反应条件下制备的羟丙基变性淀粉糊性质做了对比研究。不同品种淀粉糊性质存在很大差别。经过羟丙基改性。淀粉糊液粘度性质、冻融稳定性、透光率、都有不同程度的改善,但凝沉性质不能准确反映羟丙基化对蜡质玉米淀粉和糯米淀粉糊液性质的改善。     

Synthesis and Application of Reactive Carbohydrates. Part VI: Application of Reactive Carbohydrates Derived from Starch and Hydrolyzed Starches to Cotton Fabric

Native starch, 15 min, 30 min, 45 min and 60 min hydrolyzed starches were converted to reactive carbohydrates via graft polymerization with acrylamide followed by methylolation with formaldehyde. The reactive carbohydrates so obtained were applied to cotton fabric according to the conventional pad-dry-cure method under different conditions. The latter included the catalytic system and the curing conditions. The pad-cure and the pad-batch methods were also applicated. Examination of the treated fabrics for nitrogen content as a measure of the extent of reaction, occuring between the methylol groups of the reactive carbohydrate and the hydroxyl groups of cotton cellulose, as well as durability of the finish on the fabric indicated the dependance of the reaction and durability on nature of both reactive carbohydrate and catalyst as well as curing conditions. Reactive carbohydrate derived from 15 min hydrolyzed starch along with mixed catalyst, namely MgCl₂ · 6 H₂O/citric acid (20:80), constitute the most appropriate finish/catalyst combination provided that application is carried out according to the pad-dry-cure method; drying is effected at 100°C for 2.5 min while curing is expedited at 130°C for 30 s.     

不同植物来源淀粉之间的理化性质的比较

本研究比较了绿豆淀粉、马铃薯淀粉、红薯淀粉、大米淀粉及玉米淀粉的理化性质,结果如下：绿豆淀粉具有最高的直链淀粉渗滤和胶凝值,并且这两个指标均与表观和总直链淀粉含量呈高度的相关关系。尽管绿豆淀粉具有最高的直链淀粉含量,但它并不显示出热糊稳定性。红薯淀粉在加热过程中具有高的膨润力和峰值黏度、高的崩溃值以及低的离水率,这表明红薯淀粉颗粒在加热时能够自由膨胀,糊的热稳定性差,淀粉的老化速率较低,而大米淀粉则与红薯淀粉相反。五种淀粉具有不同的胶稠度,马铃薯淀粉最高,而大米淀粉最低。离水率与直链淀粉含量不呈现明显的相关关系,因此其值的大小可能受其他因素的影响。     

不同品种南瓜淀粉的理化特性对比研究

对比研究了三种不同品种南瓜(蜜本、东升、翠栗)淀粉的理化特性。结果表明:三种南瓜淀粉中脂肪和蛋白质含量分别在0.15-0.25%和0.09-0.57%之间;直链淀粉和可溶性直连淀粉含量则依次在26.4-29.0%和4.48-7.40%之间,东升淀粉中直链淀粉和可溶性直链淀粉的含量明显高于其他两种南瓜淀粉。淀粉颗粒大小均在5-15μm之间,平均直径为10μm,属于偏小的淀粉颗粒,且多为无规则的椭圆或卵圆形。结晶结构均属于B型,结晶度分别为30.9%、42.7%、43.3%。东升和翠栗淀粉的起始糊化温度和糊化终止温度范围分别为73.21-82.76℃、78.66-89.88℃,而蜜本淀粉出现双峰现象,其糊化温度范围为69.00-75.67℃和77.70-86.17℃。蜜本淀粉具有较低的溶解度和膨胀度,凝沉稳定性较差,透光率最高;东升淀粉的溶解度和透明度较低,但凝沉性和冻融稳定性较好;而翠栗淀粉的溶解度和膨胀度最高,但冻融稳定性最差。     

不同品种大米淀粉的流变学特性研究

以不同品种大米淀粉为材料,研究淀粉糊的流变学特性,温度、淀粉糊浓度对黏度系数、流变指数的影响,为淀粉质食品的原料选择和加工提供参数。结果表明,大米淀粉糊呈假塑性流体的特性。不同品种大米淀粉湖的流变特性有较大差异,金优和放心米的热稳定性较差,大米淀粉糊的黏度系数为0.1~11。黏度系数和流变指数对温度和浓度对有较大的依赖性。大米淀粉的流动能约为1.66×106J/mol~20.53×106J/mol。     

Properties of Starches from Australian Wheats. Part 2: Some Physico-chemical Properties

Various physico-chemical properties of starches isolated from 21 Australian wheat varieties were assessed. Molecular weights varied between the starches and were lower in those from soft wheats. Proportions of small granules were significantly correlated with starch amylose and protein contents; those of large granules correlated negatively with fat content. Granule crystallinity was correlated with hardness of the parent wheats. Gelatinisation temperatures, measured by differential scanning calorimetry, varied between the starches within the range of 46–79°C. Enthalpies of gelatinisation, 4.6–13.3 J/g of dry starch, were correlated with both amylopectin content and wheat hardness. Minimum moisture for gelatinisation, 0.15–0.56 wa-ter/g of dry starch, was significantly correlated with both amylose and fat contents of the starch.     

Non‐contact Atomic Force Microscopy of Starch Granules Surface. Part II. Selected Cereal Starches

Atomic Force Microscopy (non‐contact method) was used to examine the surface of starch granules of selected cereals. Depressions which might be typical surface pores or ends of penetrating channels were observed in case of all examined granules. The size and shape of these depressions depended on the botanical origin of the starch. Regions of relatively flat surface without visible structures, pores and protrusions could be detected on the granules studied.     

Properties of Sweet Potato Starches from Different Tissue Zones

Sweet potato starches prepared from the peel ( P ), cambium ( C ), and inner-tissue ( IT ) were tested for physicochemical properties. The average granule sizes of the IT starches were tended to be larger than those of the P and C starches. Amylose contents of starches from the different tissue zones did not differ significantly. The onset and peak temperatures ( T _o, T _p ) of the P starches determined by differential scanning calorimetry (DSC) were somewhat high. The C starches were readily digested by the four glucoamylases.     

Studies on Sago Starch. Part I: Characterization and Comparison of Sago Starches Obtained from Metroxylon sagu Processed at Different Times

This paper reports on a study undertaken to determine some of the factors responsible for the variability shown by sago starch, which at present severely limits the commercial value of this material. Two batches of sago starch extracted from Metroxylon sagu species were characterized physicochemically and structurally. One batch was white in colour while the other was reddish-brown. The latter contained significantly more protein (0.06%) than the former (0.015%). Non-proteinaceous material constituted 40% of the total nitrogen in the former. The ionic contents of the two batches of starch exhibited a similar ion profile except for the following striking differences. The white batch contained 20-fold more phosphorus and 15-fold more aluminium whilst the reddish-brown batch contained double the quantity of iron and calcium. The solubility and swelling capacity of both batches were also different. Amylographic representation was used to reveal the strength of starch granules during pasting. Scanning electron microscopy disclosed different degrees of pitting between the two batches, the morphology of which were also shown to be disparate. Flow curves also displayed significant differences in the rheological behaviour.     

Properties of Starches from Australian Wheats. Part 1: Separation of Starch and Gluten

Starch and gluten were isolated from flours milled from 21 Australian wheat varieties. Relative yields of starch and gluten varied in general accord with flour protein content. Recoveries of total solids (starch plus gluten) ranged from 67.6% to 85.1% amongst the varieties. Significant differences in proximate composition and amylose content were observed between the isolated starches. This was especially so for starch protein content which was significantly correlated with wheat hardness. Potential benefits exist for the starch/gluten industry in selecting wheats on the basis of minimal loss of total solids during the process, and for purity and amylose content of the isolated starch.     

Relationships Between Selected Properties of Starches from Different Corn Lines

Starch was isolated from the corn lines obtained by crossing two different germ pools (MS and Tux pool) and evaluated for amylose content, swelling power, solubility, water binding capacity (WBC) and syneresis. The gelatinization (T_o, T_p, T_c, ΔH_gel, PHI & R) and pasting (pasting temperature, peak viscosity, breakdown viscosity, final viscosity and set back) properties of starches were measured using Differential Scanning Calorimeter (DSC) and Rapid Visco Analyzer (RVA), respectively. The relationships between different properties were also determined using pearson correlation coefficients. Amylose content was negatively correlated to swelling power and WBC (p < 0.05). Several significant relationships were also observed between thermal and pasting properties of isolated starches. Transition temperatures (T_o, T_p & T_c) and PHI showed positive correlation with peak, trough and breakdown viscosity (p < 0.05). Syneresis of starches was positively correlated to amylose content (p < 0.05).     

Studies on the Gelatinization of Starches. Part 2. Effect of Lower Alcohols on the Gelatinization of Cereal Starches

The effect of lower alcohols (methyl to amyl alcohol) on the gelatinization of cereal starches was studied by means of amylography and the determination of degree of gelatinization by glucoamylase digestion and iodine affinity. The straight chain primary alcohols other than methyl alcohol considerably decreased the transition temperature of the amylograms of these starches with the increase of molecular weight. The characteristic modification of the amylograms by these alcohols was inferred to be due to the exchange of the alcohols for the lipids in the amylose-lipids complex of starch.     

不同品种鹰嘴豆淀粉糊与凝胶特性研究

以不同品种的鹰嘴豆Kabuli和Desi为原料,采用快速黏度仪、质构仪和流变仪研究淀粉糊与凝胶特性的差异。研究表明:Kabuli淀粉在糊化过程中的峰值、谷值、最终黏度等特征值均高于Desi淀粉,而降落值、回值及成糊温度却低于Desi淀粉。Kabuli淀粉的品质优于Desi淀粉,但这2种鹰嘴豆淀粉糊的糊丝均属于短糊系列。在不同热过程中Desi淀粉形成凝胶速度快,强度大;Kabuli淀粉的凝胶强度随温度的变化是可逆的。Kabuli淀粉凝胶破裂强度、弹性模量均小于Desi淀粉凝胶。     

Structure and Viscoelastic Properties of Starches Separated from Different Legumes

A comparison between the morphological, structural, thermal and viscoelastic properties of starches separated from pigeon pea, chickpea, field pea, kidney bean and blackgram was made. The shape of the starch granules in the different legumes varied from oval to elliptical or spherical. X-ray diffraction of the legume starches indicated a typical C-pattern (mixture of A- and B-type). Granules of blackgram and pigeon pea starch had a higher degree of crystallinity than those of field pea and kidney bean starches. Apparent amylose content of field pea, kidney bean, chickpea, blackgram and pigeon pea starch was 37.9%, 36.0%, 34.4-35.5%, 32.9-35.6% and 31.8%, respectively. Distribution of isoamylase-branched materials among the starches revealed that the proportions of long and short side chains of amylopectin ranged between 13.6-18.5% and 41.7-46.5%, respectively. Field pea and kidney bean starch had the highest apparent amylose content and the lowest amount of long side chains of amylopectin, respectively. Blackgram and pigeon pea starch possessed higher proportions of both long and short side chains of amylopectin than field pea and chickpea starches. The onset, peak and conclusion temperatures of gelatinization (T_o T_p and T_c, respectively) were determined by differential scanning calorimetry. T_o and T_c ranged from 59.3 to 77.3°C, 66.8 to 79.6°C, 55.4 to 67.6°C and 68.3 to 69.3°C, respectively, for chickpea, blackgram, field pea and kidney bean starch. The enthalpy of gelatinization (ΔH_gel) of field pea, kidney bean, chickpea, blackgram and pigeon pea starches was 3.6, 3.0, 2.6-4.2, 1.6-1.7 and 2.6 J/g, respectively. Pastes of blackgram and pigeon pea starches showed lower storage and loss shear moduli G′ than field pea, kidney bean and chickpea starches. The changes in moduli during 10 h at 10°C revealed retrogradation in the order of: field pea> kidney bean> chickpea> blackgram> pigeon pea starch. In blackgram and pigeon pea starches, the lower proportion of amylose plus intermediate fraction and higher proportion of short and long side chains of amylopectin are considered responsible for the higher crystallinity, gelatinization temperature and enthalpy of gelatinization.     

不同品种苦荞麦淀粉的主要理化性质

研究了不同种类苦荞淀粉的性质。采用扫描电镜(SEM)拍摄了苦荞淀粉颗粒的形态;用X-射线衍射仪测定了X衍射图样及结晶结构;用快速黏度分析仪(RVA3)对各个淀粉黏度进行了测定;并与玉米淀粉进行了比较。同时测定了淀粉糊的透明度、凝沉曲线等性质。