Cationization of Waxy and Normal Corn and Barley Starches by an Aqueous Alcohol Process

When an aqueous alcoholic-alkaline solvent was used, cationization of normal and waxy corn and barley starches was achieved with high degrees of substitution (DS) and reaction efficiency (RE) in the absence of gelatinization inhibitor salts. Ethanol was a more effective solvent than methanol or 2-propanol, and alcohol concentrations could vary between 35–65%. Maintaining a starch to water ratio of 1:1 (w/w) was critical, but DS values were proportional to the concentration of cationic reagent, 3-chloro-2-hydroxypropyltrimethylammonium chloride. At 50°C, cationization was essentially complete within 6h but nearly the same DS could be achieved in 1h at 70°C.     

Endosperm Structure and Physicochemical Properties of Starches from Normal,Waxy, and Super-Sweet Maize

Maize is a main botanical source used for extraction of starch in the world market. New maize cultivars with different amylose contents and special starch metabolism characteristics have been generated. Three types of maize cultivars, namely, normal maize, waxy maize (wxwx homozygous mutant), and super-sweet maize (sh2sh2 homozygous mutant), were investigated to determine differences in endosperm structures, morphologies, and physicochemical properties of starches. Maize kernels exhibited significantly different contents of total starch, soluble sugar, and amylose. Normal maize kernels contained the largest proportion of floury endosperm, followed by waxy maize and then super-sweet maize. Normal maize starch and waxy maize starch were larger in size than super-sweet maize starch. Normal maize starch and waxy maize starch were spherical and polygonal in floury and vitreous endosperms, respectively. Super-sweet maize starch was spherical both in floury and vitreous endosperms. Waxy maize starch showed the strongest birefringence patterns, the highest crystallinity and the largest proportion of ordered structure in external region of granules, and the largest proportion of double helix components, followed by normal maize starch and then super-sweet maize starch. Waxy maize starch showed the highest peak viscosity, trough viscosity, breakdown viscosity, gelatinization temperatures (i.e., gelatinization conclusion temperature, gelatinization onset temperature, gelatinization peak temperature, and gelatinization enthalpy). By contrast, super-sweet maize starch showed the lowest corresponding values for these parameters.     

The Structure of Waxy Corn Starch: Effect of Granule Size

The granules of waxy corn starch were isolated and various samples were separated by size and classified according to their average diameter in: non-separated granules (N), granules with diameter < 15 μm (S) and granules with diameter ≥ 15 μm (L). The samples were hydrolyzed by bacterial α-amylase and fungal amyloglucosidase. The starch granules remaining after enzymatic hydrolysis were analysed by X-ray diffraction and optical and scanning electron microscopy. Sephadex G-50 gel permeation chromatography of the dissolved residues from the hydrolysis of the N and S samples was performed directly and after successive enzymatic digestion with pullulanase and β-amylase. The results showed that the percentage of hydrolysis increased with a decrease in diameter. No apparent differences in waxy corn starch when observed under light and scanning electronic microscope were observed, regardless of diameter and enzyme action, although both large and small granules showed extensive surface corrosion after enzymatic attack. X-ray analysis suggested a decrease in the quantity of crystalline areas in the smaller granules, which would explain the high percentage of hydrolysis evidenced by these granules. The elution patterns of the α-glucans of both starches (N and S) were similar and reveled the presence of two fractions which were not susceptible to α-amylase and amyloglucosidase attack suggesting that these fractions were involved in the waxy corn starch crystalline regions. Debranching with pullulanase followed by gel-permeation chromatography showed that the amylopectins from the starch granules studied contained three groups of unit chains instead of the two reported in the literature.     

Effect of Aqueous Ethanol Cationization on Functional Properties of Normal and Waxy Starches

Cationic starch ethers of normal and waxy corn, normal and waxy barley and normal pea starch were prepared by an aqueous alcoholic process for evaluation of their functional properties as compared to the native starch controls. The native starches exhibited a wide range in average granule size (10–21 μm diameter), amylose content (0–34%) and swelling power (13–31). Cationization to degrees of substitution (DS) of 0.030–0.035 with 3-chloro-2-hydroxypropyltrimethylammonium chloride resulted in marked increases in swelling power of all starches, with little corresponding increases in starch solubility. Cationization also decreased the onset of endothermic transitions and pasting temperatures quite substantially, and promoted the development of sharp peak viscosities in the amylographs of all normal and waxy starches, including that of pea starch. Final cold viscosities of the cationic starches exhibited positive setbacks, and the cooked starch gels, after storage for 7 days at 4°C and −15°C, showed no syneresis. All cationic starches except for waxy corn were more susceptible to α-amylase hydrolysis than native control starches. The general improvement in functional properties, especially in the waxy corn, waxy barley and pea starches, due to the aqueous alcoholic-alkaline cationization process would greatly enhance their industrial applications.     

Studies on the Starches of Barley Genotypes: The Waxy Starch

Two varieties of waxy barley originating from Japan, Sumiremochi and Mochimugi, have been characterized in detail for the first time. These two glutinous starches were found to be essentially identical. Both contained less than 0.5% of amylose, had a β-amylolysis limit of 53% conversion into maltose, and an average length of unit-chain of about 23 glucose units. The weight average molecular weight was 300 × 10⁶. These properties are characteristic of amylopectin. The iodine binding capacity of six other varieties of Japanese waxy barley has been measured and apparent amylose contents of 3 to 13% were obtained. Possible reasons for the presence of this amount of amylose are discussed.     

普通玉米杂交种间淀粉糊化过程中热力学性质的差异研究

采用湿法在试验室条件下提取了52种普通玉米杂交种淀粉。采用差示扫描量热仪(DSC)分析了这些玉米杂交种淀粉的糊化过程中的热力学性质。结果表明:52种普通玉米杂交种间淀粉糊化过程中的热力学性质存在明显区别:热焓值变化范围为8.95~15.54 J/g,起始糊化温度、峰值糊化温度、终止糊化温度及温度变幅的变化范围分别为64.72~70.28℃、70.37~75.03℃、77.16~84.16℃及9.49~17.43℃;52种普通玉米杂交种淀粉平均热焓值、起始糊化温度、峰值糊化温度、终止糊化温度及温度变幅分别为10.87 J/g、68.17℃、72.68℃、81.01℃和12.85℃;某些热力学性质参数间存在显著的相关性;依据热焓值大小,可以将52种普通玉米杂交种分为5个组别。     

Fractionation and Characterization of Dent Corn and Amylomaize Starch Granules

Starch granules of dent corn and Classes V and VII amylomaizes were fractionated according to size by an aqueous differential sedimentation procedure. The sized fractions were characterized by microscopy and by a modified method for determining their iodine binding capacities. Results show an inverse relationship between granule size and iodine binding capacity in the amylomaizes. Ordinary dent corn does not show this. The percent apparent amylose in the fractions of amylomaize V starch amounted to 40% for the largest size particles and 52% for the smallest ones; for amylomaize VII starch, 46% for the large particles and 70% for the small particles. Dent corn averaged 23% apparent amylose.     

Structure and Physicochemical Properties of Endosperm Starches of a Waxy Allelic Series and Their Respective Normal Counterparts in the Inbred Oh43 Maize Background

Research over the past three decades has greatly increased our understanding of the biochemical genetics of various waxy (wx) alleles of maize, but our knowledge about the structure and physicochemical properties of endosperm starches obtained from the wx alleles is still incomplete. We further investigated the structure and physicochemical properties of endosperm starches from a wx allelic series and their normal counterparts in the Oh43 inbred background. Starch granules were prepared from mature kernels of wx mutant alleles; wx-C31, wx-R, wx-90, wx-a, wx-B3, wx-m-1, wx-m-8, and wx-S5, and their respective normal counterparts in the inbred Oh43 maize background. Measurements of absorption spectra of starch-iodine complexes and by gel permeation chromatography of Pseudomonasisoamylase-debranched starches showed that all of the starches from the wx allelic series were uniquely waxy type in characteristics, and their normal counterparts were characteristically normal type. Pasting characteristics of starch granules and retrograded starches of the wx allelic series and their respective normal counterparts were investigated by differential scanning calorimetry (DSC). The peak temperature (Tp) and conclusion temperature (Tc) values from starches of the wx allelic series were slightly higher than those of their respective normal counterparts and the ΔHs of starches of the wx allelic series were greater than those of their respective normal counterparts. The onset temperature (To), Tp, and Tc of all retrograded starches were very similar, however, the ΔHs of the retrograded starches of the wx allelic series were greate than those of their respective normal counterpart. Starch granules of the wx allelic series were hydrolyzed more rapidly than those of their respective normal counterparts.     

Enhancement of Resistant Starch (RS3) in Amylomaize,Barley, Field Pea and Lentil Starches

Native starches isolated from amylomaize. Glacier high amylose barley, field peas and lentils contained 3–5% (w/w) resistant starch (RS3). Retrograded gels that were prepared from these starches had higher RS3 (6–9%) contents. The effects of gel concentration (% starch), storage temperature and time on the RS3 content of the retrograded gels were investigated; the optimum RS3 content was determined in gels prepared at = 10% (w/v) starch concentration and stored under = 20°C for = 5 days. Annealing of the retrograded starch gels by heating and cooling cycles, further enhanced RS3 content to 9–19%; the effect of annealing temperature and number of heat-cool cycles on the RS3 content of the annealed gel were studied. The hydrolysis of retrograded starch gels by pulanase enzyme or acid (2.2 N HCl), prior to annealing, enhanced the RS3 formation during annealing; the enzyme or acid treatment increased RS3 content of the annealed gel to 15–24% or 17–24%, respectively. The potential molecular mechanism that is responsible for the RS3 increase is discussed.     

Preparation and Properties of Benzyl Corn Starches

Benzyl corn starches (DS 0.02–0.16) were prepared by reacting starch with benzyl chloride in an alkaline aqueous medium at 65°C, and the pasting properties of the starches were investigated. Reaction yield with 20% benzyl chloride (based on starch weight) for 12 h was increased from 26.7% to 60.5% as the NaOH addition increased from 3% to 8% (based on starch weight), and became relatively constant thereafter. With 20% benzyl chloride and 8% NaOH, degree of substitution (DS) reached 0.16. Light transmittance and viscosity of starch paste were decreased as DS increased. Low viscosity and opaqueness of the paste indicated that the benzyl groups increased hydrophobicity, and reduced solubility of the starch. Onset temperature (T_o) for starch melting measured by a Differential Scanning Calorimeter thermogram was decreased as DS increased up to 0.1. But above DS 0.1, T_o increased. Melting enthalpy was also decreased as DS increase because of the incomplete gelatinization. Solubility in aqueous methanol (80%) increased near 2% as DS reached 0.16. Maximum wavelength and absorbance of the iodine complexes of benzyl starch were decreased with benzylation.     

不同淀粉在鱿鱼鱼糜制品中的应用

探讨了在鱿鱼鱼糜制品中添加不同种类的淀粉(玉米淀粉、木薯淀粉、马铃薯淀粉、小麦淀粉和变性马铃薯淀粉)以及β-环糊精等对鱿鱼鱼糜制品凝胶性能、弹性、持水力、色泽、风味的影响。结果发现:添加淀粉能有效提高鱿鱼鱼糜的凝胶强度、持水力,但是会使色泽有所下降;而添加β-环糊精能提高鱼糜凝胶白度,但是对提高凝胶强度没有作用。     

Comparative Acid Modification of Various Starches

Eight starches (maize, sorghum, finger millet, waxy and nonwaxy rice, chick pea, tapioca and potato) were acid modified with 0.5N HCl at 50°C. Alkali fluidity number (AFN) increased progressively with time of modification, and was highest in cereal followed by root, legume, and tuber starches. However, reduction in the number average molecular weight (M̄_n) was in the reverse order. Potato starch had the highest M̄_n, among the nonwaxy native starches and showed the greatest fall upon modification, whereas cereal starches had the least M̄_n in native form and showed the least fall. In fact, there was a clear proportionality between the M̄_n, of native starch and the extent of its hydrolysis under any given set of conditions. This relationship could be expressed by two intersecting lines, one for grains and one for root and tuber starches. When acid modified starches were recovered and dried without neutralization, hydrolysis still continued strongly in potato starch and slightly in tapioca, finger millet and sorghum starches. Other starches showed no change.     

Development Changes in Fine Structure of Starches of Several Endosperm Mutants of Maize

Distribution of components of maize starches from several endosperm mutants sampled at three stages of development were investigated by gel filtration after debranching by isoamylase. The waxy (wx) starches consisted of only amylopectin, and the distribution of components did not change during development. In other starches: normal, amylose-extender (ae), dull (du), sugary-1 (su₁) and sugary-2 (su₂) starches, amylose contents increased during the 20–35 days after pollination (DAP) period of development. The ae, du, su₁ and su₂ mutants produced high-amylose starches, while amylopectin of su₂ was normal type and those of ae, du and su₁ were novel type, and ae starches possessed longer average chain-lengths of amylopectin. Phytoglycogens were prepared from su₁ kernels during development and their characteristics were compared with those of su₁ starches. The characteristics of phytoglycogens did not change during the developmental phase studied and the average chain-lengths of phytoglycogens were shorter than those of amylopectin of su₁ starches at each stage of development.     

In vitro Digestibility of Hydroxypropyl Maize,Waxy Maize and High Amylose Maize Starches

Hydroxypropyl derivatives of maize, waxy maize and high amylose maize starches were prepared and characterized. The in vitro digestibility of the raw and gelatinized starches and their derivatives was compared using porcine pancreatic α-amylase. Digestibility of the unmodified starches decreased in the order waxy maize > maize > high amylose maize. Increasing molar substitution (MS) caused a decrease in digestibility for all starch types after gelatinization. Raw maize and high amylose maize starch derivatives showed an initial decrease in digestibility followed by increases at higher MS levels. The digestibility of the raw waxy maize starch derivatives showed a continuing drop as MS increased.     

羟丙基化改性对普通玉米杂交种淀粉糊化热力学性质的影响

采用湿法在实验室条件下提取18种普通玉米杂交种淀粉,并制备了羟丙基淀粉.采用差示扫描量热仪(DSC)分析了原淀粉和羟丙基淀粉的糊化过程中的热力学性质.结果表明羟丙基化改性显著降低了所有普通玉米杂交种淀粉的热焓值、起始糊化温度、峰值糊化温度和终止糊化温度,平均降幅分别为29.6%、13.9%、12.2%和7.8%.但羟丙基化改性对不同的普通玉米杂交种淀粉热力学性质的影响程度明显不同,即热力学性质各参数的降幅在杂交种间存在显著差异,热焓值、起始糊化温度、峰值糊化温度及终止糊化温度的降幅的变化范围分别为10.95～47.15、9.1%～16.9%、8.7%～14.3%、4.8%～12.2%.     

Studies on Starches of High Amylose-Content. Part 14. The Fractionation of Amylomaize Starch by Aqueous Leaching

Amylomaize starch is known to contain an anomalous material which does not conform to the classical definitions of either amylose or amylopectin. A detailed study of this polysaccharide has not yet been carried out, principally because of the difficulty of obtaining it in sufficient quantity. This paper presents a rapid and simple method by which the isolation may be achieved.     

热处理对直链淀粉扩增,蜡性及正常玉米淀粉物理性质和酶解率的影响

对直链淀粉扩增（ａｅ），蜡性（ＷＸ）及正常玉米淀粉经热处理（ａｕｔｏｃｌａｖｉｎｇ）后，其物理性质和酶解率的变化进行研究。淀粉经热处理后，除蜡性淀粉其峰值粘度增加外，所有淀粉的峰值粘度降低，且糊化温度提高，热处理增加扩增淀粉的热焓，但降低蜡性淀粉的ΔＨ；同时对正常玉米淀粉的ΔＨ几乎无影响。热处理使蜡性和正常玉米淀粉的硬度和粘结力增加，但使扩增淀粉的硬度和粘结力降低；同时使所有淀粉的弹性降低。热处理     

糯玉米交联淀粉的制备及性质研究

本文采用混合酸酐交联法，用糯玉米淀粉制备糯玉米交联淀粉，并着重研究了糯玉米交联淀粉的性质如交联度、冻融稳定性、膨胀度、透明度和凝沉性。试验表明：通过交联作用制成的糯玉米交联淀粉，大大改进了原淀粉的性能。具有交联度高（沉降积为0．75mL）、冻融稳定性好（析水率最低为56．3％）、抗凝沉性强（凝沉性最弱）和具有一定膨胀力（膨胀度低于原淀粉但高于其它变性淀粉）和透明度（透光率比糯玉米淀粉低，但较其它淀粉而言仍具有较高的透光率，说明糯玉米交联淀粉具有较高的透明度）。     

糯玉米粉、淀粉和脱脂淀粉的理化特性研究

以4个糯玉米品种为材料,比较分析了糯玉米粉、淀粉(脱蛋白)和脱脂淀粉(脱蛋白脱脂)的理化特性.结果表现,脱蛋白或脱蛋白脱脂处理不改变材料的结晶类型,各材料均表现为典型的"A"型衍射图谱.理化特性在糯玉米粉、淀粉和脱脂淀粉间存在显著差异.结晶度、膨胀势、回复值、峰值时间和糊化温度以糯玉米粉最高,脱脂淀粉最低;溶解度、峰值黏度和谷值黏度以淀粉最高,米粉最低;透光率以脱脂淀粉最高,米粉最低;但4个糯玉米品种的终值黏度变化趋势不甚明显.     

羟丙基直链扩增、蜡性和正常玉米淀粉功能性质的研究

本文对ＳｔａｒｃｈＡｕｓｔｒａｌａｓｉａ公司提供的直链扩增玉米淀粉（Ｈｉ－Ｍａｉｚｅ，直链淀粉含量６６％和ＧＥＬＯＳＥ５０，直链淀粉含量４７％），蜡性玉米淀粉（ＭＡＺＡＣＡ３４０１，直链淀粉含量３．３％和正常玉米淀粉（直链淀粉含量２２．４％）进行羟丙基化反应，并对其功能性质和酶解率进行研究。与母体淀粉相比，羟丙基化反应降低所有淀粉的糊化温度，同时除蜡性玉米淀粉其粘度略有降低外，所有淀粉的粘度均提高。ＤＳＣ（ｄｉｆｅｒｅｎｔｉａｌｓｃａｎｎｉｎｇｃａｌｏｒｉｍｅｔｒｙ）结果显示，所有羟丙基淀粉与未改性淀粉相比均有较低的Ｔｏ，Ｔｐ，Ｔｃ和△Ｈ。但是羟丙基化反应使膨胀率和溶解率得到提高。淀粉经羟丙基化反应后，所有淀粉凝胶的硬度（ｈａｒｄｎｅｓｓ）和粘着力（ａｄ－ｈｅｓｉｖｅｎｅｓｓ）均降低，同时所有淀粉的透光率和酶解率均提高。