Pollen Starch from Amylomaize

Starch has been extracted from the pollen of band 5 and band 7 amylomaizes which are homozygous for the amylose extender (ae) gene. Microscopic examination showed the starch granules to be small, prolate ellipsoids, having minor diameters of approximately 0.5 μ and major diameters of 1–2 μ. Potentiometric iodine titration of the starches showed the apparent amylose content to be high, and to be grossly dependent on the temperature of measurement. This behavioural pattern is similar to that observed for the endosperm starches of amylomaize. It is therefore concluded that the starches of the gametophytic and sporophytic generations of amylomaize are similar in type.     

A Novel Type of Corn Starch from a Strain of Maize. Part 3. The Properties of the Starch from Amylo-waxy Maize and Its Hybrids with Waxy Maize

A pair of hybrids were produced by alternative crossbreeding of waxy maize with amylo-waxy maize which had double recessive genes, amylose extender (ae) and waxy (wx). Investigation of the starches proved that they did not coincide with waxy starches. Hidden amylose extender genes also participated in the starch produced in the endosperm of hybrid maize. Amylo-waxy starch looks promising as a new material of food industry.     

Effect of Environmental Temperature During Development of Rice Plants on Some Properties of Endosperm Starch

Starch granules were isolated from polished grains of rice plants (Oriza sativa L.) grown under controlled temperature conditions. Distribution of isoamylase-debranched starch materials and unit chain-length of amylopectin were examined by gel-filtration on columns. Higher environment temperature decreases amylose concentration in endosperm starches of Japanese rice cultivars. The amylose concentration in the endosperm starch is determined by the environment temperature 5 – 15 days after heading. Interestingly, the higher environment temperature seemed to increase the amount of long B chains and decrease that of short chains of amylopectin. The effect of environment temperature on pasting characteristics of starch by DSC, starch-granule digestibility by amylases and X-ray diffractograms of starch was also investigated.     

Characterization of High-amylose Type Endosperm Starches of Rice Plants Cultivated in Asia

Starch granules were prepared from 14 indica rice grains which were collected from various places of Asia and had the amylose content of 28% and over by a blue value method. The starches were high- and medium-amylose types by the enzymatic and chromatographic method. However, none of them belonged to the type of high amylose mutants which were induced by the chemical mutagen treatment of a japonica rice cultivar: Kinmaze and possessed similar characteristics of endosperm starch to that of the amylose-extender (ae) mutant of maize (Zea mays L.).     

The Interaction of Endosperm Genotype and Genetic Background. Part I. Differences in Chromatographic Profiles of Starches from Nonmutant and Mutant Endosperms

The effect of maize endosperm genotype and genetic background on variation of endosperm starch properties has been examined by gel filtration. Nonmutant, and single, double and triple mutant combinations of the endosperm genes amylose-extender (ae), dull (du), sugary (su), and waxy (wx) in four maize inbred lines were compared. The major effects of endosperm genes on starch properties did not vary as a result of genetic background. Starches from wx endosperms contained no amylose. The mutants ae, du and su resulted in starches with increased amylose content. Genetic background did affect starch properties in predictable ways. For example, the production of amylose in mutant endosperms was higher in the dent inbred background, followed by the sweet corn inbreds. However, the production of low molecular weight amylopectin and intermediate polysaccharide fractions was greatest in a sweet corn inbred background, We conclude that the material included in this study will be valuable in future investigations designed to delineate the interaction of genetic background and endosperm genotype in starch biosynthesis and starch properties.     

Characterization of Endosperm Starch from High-amylose Mutants of Rice (Oryza sativa L.)

The structure and properties of endosperm starch from high-amylose mutants of rice were examined. The starch in the mutants was characterized by a higher content of amylose and loosely branched amylopectin with longer chains compared with non-mutant starch. The starch granules in the mutants showed high temperatures of gelatinization and a type B pattern in X-ray diffractometry. These properties were similar to those of amylose-extender (ae) starch of maize. The effect of locations where rice plants were grown on the endosperm starches of one high-amylose mutant and a non-mutant was also investigated.     

Structural and Physicochemical Properties of Endosperm Starches Possessing Different Alleles at the Amylose-extender and Waxy Locus in Maize (Zea mays L.)

The structure and some physicochemical properties of endosperm starches from seven amylose-extender (ae) and two waxy (wx) alleles of maize (Zea mays L.) were studied. Starches prepared from mature kernels of six ae mutants, Oh43 inbred line ae (standard ae), ae-RWB-2 and ae-RWB-3, and W23 × L317 hybrid line ae-PP, ae-Bol 561 and ae-emll, were uniquely ae type, as was concluded from B type X-ray diffractograms; high gelatinization temperatures determined by differential scanning calorimetry (DSC); with poor starch-granule digestibility to amylase; high amylose (37—45 %) and high intermediate fraction (13—18 %) contents; and low ratios (1.0—1.2) of long α-1,4-chains to short α-1,4-chains of amylopectin determined by gel permeation chromatography (GPC) of isoamylase-debranched starches. The results also indicated that different ae alleles had different effects on the amylose content of endosperm starches. Mature kernels of Oh43 ae-RWB-1 mutant showed tarnished and translucent phenotype characteristics of the ae genotype but contained endosperm starch with 21—22 % of amylose which was lower than that of the Oh43 normal counterpart. Both wx-B and wx-C (standard wx) genes have similar effect on structure and physicochemical properties of waxy starches of A632, B37, C105, Oh43, and W64A inbred lines.     

Effects of the Barley amo1 and wax Genes on Starch Structure and Physicochemical Properties

Starch structural mutants showing abnormal endosperm characteristics have been used for investigating the effects of the mutation on structure and physicochemical properties of starches. Inbred lines of barley cultivars ‘Shikoku Hadaka 97’ and ‘Glacier AC38’ were used to investigate the impact of amo1 and waxy genes on starch properties. The amo1 type starch had high apparent amylose content and low starch content. The amo1+waxy type starch contained very little amylose. The content of long chains of amylopectin as detected with high‐performance size‐exclusion chromatography (HPSEC) was decreased, and that of amylopectin chains with the degree of polymerization (DP) of 12‐36 was increased in amo1 and amo1+waxy type starches. The amo1 and amo1+waxy type starches exhibited high gelatinization temperatures and low gelatinization enthalpies.     

Gelatinisation Characteristics and Enzyme Susceptibility of Different Types of Barley Starch in the Temperature Range 48–72°C1

The gelatinisation temperatures, pasting characteristics and enzymic susceptibilities in the temperature range 48–72°C of normal, high amylose, low amylose and zero amylose barley starches were determined. Normal starches had the lowest gelatinisation temperatures, but low and zero amylose starches had the lowest pasting temperatures. Normal starches were the most readily soluble in water at 48–60°C in the presence of a mixture of α‐amylase, β‐amylase and limit dextrinase and were most readily broken down to reducing sugars by these enzymes. High amylose starch was the most resistant to enzymic hydrolysis in the temperature range 48–72°C and, hence, produced the lowest level of reducing sugars.     

热处理对不同直链淀粉含量的玉米淀粉理化性质的影响

采用快速黏度分析法、离心法、差示扫描量热分析法、动态流变仪分析法等,研究了干热与湿热处理对3种不同直链淀粉含量的玉米淀粉糊化性质、膨润性质、热力学性质、流变性质的影响,为淀粉的物理改性研究和加工应用提供理论依据。结果表明,干热处理使淀粉更易糊化,表现为3种玉米淀粉糊化温度降低,溶解度、膨胀度增加。湿热处理加大糊化难度,使3种玉米淀粉的糊化温度升高,膨胀度降低。热处理使玉米淀粉糊稠度、糊化焓值降低。蜡质玉米淀粉经热处理后,溶解度和老化率增加。流变性质测定结果表明,湿热处理不利于高直链玉米淀粉黏弹性凝胶的形成。     

Microstructural and physicochemical properties of heat-moisture treated waxy and normal starches

Starches from normal rice (21.72% amylose), waxy rice (1.64% amylose), normal corn (25.19% amylose), waxy corn (2.06% amylose), normal potato (28.97% amylose) and waxy potato (3.92% amylose) were heat-treated at 100 °C for 16 h at a moisture content of 25%. The effect of heat-moisture treatment (HMT) on morphology, structure, and physicochemical properties of those starches was investigated. The HMT did not change the size, shape, and surface characteristics of corn and potato starch granules, while surface change/partial gelatinization was found on the granules of rice starches. The X-ray diffraction pattern of normal and waxy potato starches was shifted from B- to C-type by HMT. The crystallinity of the starch samples, except waxy potato starch decreased on HMT. The viscosity profiles changed significantly with HMT. The treated starches, except the waxy potato starch, had higher pasting temperature and lower viscosity. The differences in viscosity values before and after HMT were more pronounced in normal starches than in waxy starches, whereas changes in the pasting temperature showed the reverse (waxy > normal). Shifts of the gelatinization temperature to higher values and gelatinization enthalpy to lower values as well as biphasic endotherms were found in treated starches. HMT increased enzyme digestibility of treated starches (except waxy corn starch); i.e., rapidly and slowly digestible starches increased, but resistant starch decreased. Although there was no absolute consistency on the data obtained from the three pairs of waxy and normal starches, in most cases the effects of HMT on normal starches were more pronounced than the corresponding waxy starches.     

The Generalized Heat Capacity/Amylose Content Function for Barley and Maize Starches

The heat capacity values of 1 % aqueous dispersions of barley and maize starches with different amylose content (1—35 %), were determined. It was shown that a rise in amylose content leads to an increase of heat capacity values. The heat capacity values were calculated per 1 % change of amylose content in barley and maize starches. The generalized function describing changes of heat capacity values versus amylose content for barley and maize starches has been established.     

Amylose Content and Chain Profile of Amylopectin from Normal,High Amylose and Waxy Barleys

The amylose content and the chain profile of amylopectin from normal, waxy and high amylose barley starches were determined after enzymatic debranching and gel permeation chromatography and the degree of branching of the amylopectin was analysed by 1H-n.m.r. spectroscopy. The normal barley starch contained around 30%, the high amylose around 40% and the waxy starch 9% amylose. The amylopectin of the high amylose starches had longer chains than those of the normal or waxy starches, especially in the molecular weight interval 5,400-8,000, but less of those below 2,400 in molecular weight. The chain length of amylopectin from high amylose barley was on average 5 units longer than those of normal or waxy barleys.     

Polarization Colors of Lightly Iodine‐stained Maize Starches for Amylose‐Extender and Related Genotypes in the W64A Inbred Line

Previous qualitative research showed that for some maize endosperm genotype starches the color of variably iodine‐stained starch granules observed by bright field microscopy (BFM) was different from the color of identically stained granules observed by polarized light microscopy (PLM). One objective of the present study was to determine the polarization color for a variety of high‐amylose and other starch genotypes in an identical genetic background. A secondary objective was to determine the iodine concentration dependence of polarization colors for the samples. Starches from the W64A inbred line were obtained from the following genotypes: normal, wx, ae, du, su2, ae wx, ae du, ae su2, and du su2. Starches were stained with iodine solutions ranging from 0.02 to 0.075% and viewed with BFM and PLM, using an auto‐exposure digital camera function. Most starches showed the first appreciable color at about 0.04percnt; I₂. Unlike normal and non‐ae‐containing starches, ae starch showed a pink polarization color, despite its blue color in bright field. Heterogeneity in polarization color was observed both within and among granules. Double mutant starches containing ae showed variable effects, depending on the combination. It is suggested that the pink polarization color of ae starch may be due to a lack of symmetrical orientation of iodinecomplexed amylose in these granules     

Action Pattern of Porcine Pancreatic alpha-Amylase on Hydroxypropyl Derivatives of Maize,Waxy Maize and High Amylose Maize Starches

Differences in the action pattern of porcine pancreatic α-amylase during hydrolysis of maize, waxy maize and high amylose maize starches and their hydroxypropyl derivatives were examined by measuring changes in blue value and reducing value during digestion. Among the unmodified starches, the degree of random attack increased in the order waxy maize < high amylose maize < maize. Increasing substitution with hydroxypropyl groups led to increased random attack for both maize and high amylose maize starches. For waxy maize starches random attack increased up to a molar substitution of 0.07 and subsequently declined.     

不同直链淀粉含量对羟丙基氧化玉米淀粉性质的影响

本文采用蜡质玉米、普通玉米和高直链玉米淀粉为原料,改变有效氯添加量,制备羟丙基氧化淀粉,通过XRD、DSC、Brabender粘度仪等测定手段,研究不同直链淀粉含量对羟丙基氧化淀粉理化性质的影响。实验表明,直链淀粉含量对羟丙基化和氧化程度影响显著,其中直链淀粉含量高有利于羟丙基化,而不利于氧化;X-射线衍射分析发现,改性淀粉没有改变晶型,随氧化程度增加,淀粉分子结晶度下降,直链淀粉含量越高,下降趋势越缓;DSC测试和Brabender粘度分析表明,直链淀粉含量直接影响到羟丙基氧化淀粉糊化特性,糊化温度:高直链普通蜡质,糊粘度:蜡质普通高直链,糊化焓:蜡质普通高直链;通过观察淀粉的偏光特性和颗粒表面形态,发现直链淀粉含量越高,羟丙基氧化淀粉的偏光十字越弱,颗粒越不易破碎。     

不同品种小米淀粉品质特性研究

选取山东农科院提供4种小米(济12、济13、保18、复1)及山东省部分地区种植2种小米(市1、市2)作为研究对象,采用1%SDS法提取小米淀粉,对不同品种小米淀粉直链淀粉含量、可溶直链淀粉含量、凝沉性、膨润性、溶解度等进行研究,并对淀粉理化指标进行相关性分析。结果显示,不同品种小米直链淀粉含量为2.27%~31.98%,其中以市1品种含量最高;复1和市2膨润力和溶解度最大;凝沉性排列次序为:高直链小米淀粉(市1)>中直链小米淀粉(济12、济13、保18)>低直链小米淀粉(复1、市2);淀粉理化指标间进行相关性分析结论为:溶解度、膨润力、凝沉体积皆与直链淀粉含量呈显著负相关。     

Solubility Behavior of Granular Corn Starches in Methyl Sulfoxide (DMSO) as Measured by High Performance Size Exclusion Chromatography

The extent of corn starch dispersibility and the relative molecular solubility of amylose and amylopectin in methyl sulfoxide (DMSO) were determined. Granular corn starches with <l, 25, 53, and 70% amylose were dispersed in 0–100% DMSO (in water) solutions at 30°C for 30 min. Maximum dispersibility for all starches (98%) was obtained when 90% DMSO/10% water was used; regular (normal) dent corn starch was equally dispersed in solutions with 88–94% DMSO. Molecular solubility, the presence of individual molecules of amylose and amylopectin, of starches was also measured (after centrifugation and filtration) by high performance size-exclusion chromatography (HPSEC). Starches were dispersed in 90% DMSO and heated for 10 min at temperatures of 35–120ºC. At low temperatures, high coefficients of variation resulted from additional DMSO solubilization after treatment. At 120ºC, 70% amylose starch was >90% solubilized, while waxy starch was only 47% solubilized. When starches were treated for 18–89 h in 90ºC DMSO, solubility stopped increasing after 67 h. High amylose starch (70%) was mostly solubilized, but 53% amylose, waxy and regular starches could only be fully solubilized after exposure to shear. Amylopectin molecules appeared more susceptible to shear induced depolymerization than amylose. The percent amylopectin in the high amylose starches reflected that as determined by iodine binding analysis and the manufacturer; while the percent amylopectin in regular starch was too low (manufacturers: 75%, HPSEC: 65%). Undispersed components were mostly amylopectin. Since amylose is fully solubilized, however, the HPSEC can be used to quickly determine percent amylose in starch.     

Physicochemical Characteristics and Functional Properties of Starch from a High β-Glucan Waxy Barley

The physicochemical properties and functional characteristics of starch from a high β-glucan waxy barley were compared with those of starches isolated from normal and high amylose barleys. Amylose content of the starches ranged from 1.9 to 34.8%. There was no relationship between amylose content and water binding capacity and gelatinization temperature of the starches. Amylose content and swelling power as well as enzyme susceptibility were negatively correlated. Waxy barley starches had a lower solubility than amylose-containing starches. High amylose barley starch registered no swelling in the Amylograph. Amylose content in starch proved to be very important for good bread- and cake baking quality. Waxy starches did not produce acceptable breads and cakes. The starch from the high β-glucan barley variety “Shonkin” will be suitable as a thickening agent, but not as an ingredient in bakery products.     

微波辐射对木薯淀粉性质影响

研究微波辐射前后木薯淀粉物化性质变化,采用微波对30%水分含量木薯淀粉进行处理,结果表明,微波处理增强对应X–射线衍射峰强度,降低膨胀度、溶解度和冻融稳定性;木薯淀粉经处理后糊化起始温度升高、粘度降低,但其粘度曲线不改变。以上数据表明,在淀粉颗粒内无定形区和结晶区直链淀粉与直链淀粉、直链淀粉与支链淀粉发生交互作用,微波处理使淀粉分子发生一定程度降解。