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.     

Effects of Cationization on Functional Properties of Pea and Corn Starches

Amylography, scanning electron microscopy and storage tests demonstrated that native pea starches were highly resistant to granule disintegration during heating in dilute slurries, resulting in low hot paste viscosity, high retrogradation and syneresis. Cationization at degrees of substitution of 0.02 to 0.05 reduced the pasting and gelatinization temperatures, increased peak viscosities and set-back on cooling but eliminated syneresis after storage at 4°C and − 15°C. The principal effects of cationization were to promote rapid granule dispersion at low pasting temperatures, yielding a molecular dispersion of amylose and amylopectin on heating to 95°C. On cooling, the gel structures were firm and the cationic groups controlled the realignment of starch chains during low temperature storage.     

Preparation of Amphoteric Starches During Aqueous Alcoholic Cationization

Use of an aqueous alcoholic-alkaline solvent allowed cationization and phosphorylation to be combined in simultaneous or sequential processes in the production of amphoteric starch. Degrees of substitution required by the paper industry were obtained in normal corn, pea and barley starches, and in waxy corn and barley starches without the need for drying and heating the cationic starches to complete the phosphorylation reaction. The amphoteric starches had increased welling power, lower gelatinization temperatures, improved paste consistency and stability, and increased α-amylase digestibility than native controls, while gel syneresis after cold storage was eliminated.     

An Aqueous Alcoholic-Alkaline Process for Cationization of Corn and Pea Starches

To develop a more efficient process for cationization of corn and pea starches, the effects of gelatinization inhibitor, type of solvent and solvent concentration, starch: water ratio, reaction temperature and 2-chloro-3-hydroxypropyltrimethylammonium chloride (CHPTAC) concentration on rate and efficiency of cationization of corn und pea starches in an aqueous alcoholic-alkaline solvent were studied during 24h of reaction time. The use of watermiscible organic solvents in the aqueous alkaline media eliminated the requirement for a gelatinization inhibitor to minimize starch swelling. The alcohol concentrations which produced high reaction efficiencies were 35-75% ethanol or 2-propanol. Optimum conditions for the reaction included 65% ethanol, 50°C and a starch:water ratio of 1:1 (w/w). The degree of substitution (DS) value increased linearly with CHPTAC concentration up to O,2M CHPTAC, but reaction efficiency (RE) decreased at the O,2M CHPTAC concentration. Cationization of starch in the aqueous alcohol solvent would be an alternative to aqueous processes because of the higher DS and reaction efficiencies that were achieved more rapidly and without the aid of other gelatinization inhibitors.     

麦芽糖对糯性谷物淀粉糊化和流变性质的影响

以大黄米、糯米、糯玉米淀粉为原料,通过快速黏度分析仪、流变仪、差示扫描量热仪以及低场强核磁研究不同添加量的(2％、6％和10％)麦芽糖对糯性谷物淀粉糊化和流变性质的影响.结果表明:麦芽糖能够提高3种糯性谷物淀粉的成糊温度,显著降低3种淀粉的峰值黏度、终值黏度和回生值;随着麦芽糖添加量的增加,3种淀粉糊的剪切应力逐渐降低...     

Modeling of Retrogradation of Waxy and Normal Corn Starches

Retrogradation behavior of waxy and normal corn starch gels stored at 5 and 21°C were investigated for 50 days by differential scanning calorimetry. The extend of retrogradation can be expressed as the ratio of retrogradation and gelatinization enthalpy values and these were 70–78% for normal corn starch and 39–68% for amioca stored at two temperatures. Higher retrogradation rates were observed at 5°C for both waxy and normal corn starch. Kinetic data were evaluated by considering retrogradation as consecutive reactions in series and by Avrami Equation. High R² values (0.97–0.98) indicated that both models can be used for prediction. The comparison of rate constants obtained by Avrami Equation indicated that both temperature and amylose content of starch affected the recrystallization rate. By the kinetic model based on consecutive reactions in series, it was proven mathematically that the rate limiting step in recrystallization of starch gels is the nucleation.     

Physicochemical Properties of Waxy and Normal Maize Starches Irradiated at Various pH and Salt Concentrations

Waxy and normal maize starches of various pH values and salt contents were prepared, irradiated with gamma rays (5–20 kGy) and their molecular structure, pasting viscosity and rheological properties determined. Average molar mass and size of both waxy and normal maize starches decreased considerably by irradiation from >338.0×10⁶ to <39.4×10⁶ g/mol and from >237.5 to <125.2 nm, respectively. Adjustments of pH had little influence on the average molar mass and size of irradiated starch, whereas incorporation of salt greatly reduced the molar mass and size of irradiated waxy and normal maize starches. As the pH increased from 4 to 8, the pasting viscosity of the irradiated starches decreased from 1032 to 279 mPa s in waxy and from 699 to 381 mPa s in normal starches. Pasting viscosity of both irradiated waxy and normal starch decreased from 689 to 358 mPa s and from 327 to 184 mPa s as the salt concentration increased from 1 to 5%. The G′ of gels, determined during cooling from 90 to 10°C or storage for 8 h, decreased in irradiated waxy and normal starches by pre‐conditioning at pH 8 and in irradiated waxy starches by pre‐conditioning at 5% NaCl. With 5% NaCl, G′ of irradiated normal maize starch during cooling increased up to the irradiation level of 10 kGy, and increased during storage for 8 h at all levels of irradiation. Incorporated salt prior to irradiation appears to induce incremental modifications in the molecular structure, rheological and retrogradation properties of starch by boosting the degradation of molecules.     

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.     

Effect of Cross-Linking on Functional Properties of Legume Starches

Refined starches from lentil, fababean and field pea contained 38.5, 32.0 and 34.2% amylose, respectively, where the water binding capacities, swelling powers, susceptibilities to amylase digestibility and amylograph viscosities were in the order: lentil > fababean > field pea. This evidence and the X-ray diffraction data suggested that the degrees of molecular association between starch chains, especially amylopectin, followed the order: field pea > fababean > lentil. Cross linking with phosphorus oxychloride decreased water binding capacity, swelling power, α-amylase digestibility and 95°C viscosity in the amylograph but increased the degree of set-back. X-ray diffraction patterns indicated that cross linking occurred mainly in the amorphous regions of the starch granule. Scanning electron microscopy showed that cross linking hindered amylose exudation. The stable hot paste viscosities of cross-linked starches would be of value where low pH and high temperature are employed during pressure cooking or sterilization while the low degree of set-back of field pea starch should improve the freeze-thaw stability and textural quality of frozen foods.     

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。     

Properties of Korean Amaranth Starch Compared to Waxy Millet and Waxy Sorghum Starches

Characteristics of waxy type starches isolated from amaranth, waxy millet and waxy sorghum harvested in Korea were evaluated. Shapes of all starch granules were polygonal or slightly round and the surfaces of waxy millet and waxy sorghum starch granules showed visible pores. Amylose contents of the three starches were between 3.2–6.0% and amaranth starch showed the highest water binding capacity (WBC) (130.7%). The swelling power and solubility of amaranth starch studied at 65.0–95.0°C increased about 13.7‐ and 14.0‐fold, respectively, with increase in temperature. Swelling power of waxy sorghum starch was the highest (72.6 at 95°C) among the starches studied, while amaranth starch had a constant swelling power and its rate of solubility increasely only slowly at temperatures higher than 75°C. From RVA data, initial pasting temperatures of amaranth, waxy sorghum and waxy millet starches were 75.7, 73.3 and 75.2°C, respectively. Peak viscosity, breakdown, and setback from trough of amaranth starch were 68.3, 16.7 and 7.5 RVU, respectively, which were the lowest values among the starches investigated. Using DSC, onset temperature of gelatinization of amaranth starch was 1.5–4.0°C higher than those of waxy sorghum and millet starches, corresponding to the RVA result. The enthalpies of gelatinization of the starches studied in our laboratory were in the range of 8.5–12.7 J/g with decreasing order of waxy sorghum > amaranth > waxy millet starch.     

Comparison of Thermal and Viscoelastic Properties of Four Waxy Starches and the Effect of Added Surfactant

The waxy starches used in this investigation (maize (WM), barley (WB) and two rice starches RD4 and IR29) showed different gelatinization temperatures (GT) and enthalpies (ΔH_G) measured with differential scanning calorimetry (DSC). The differences in GT and ΔH_G could only partially be related to X-ray crystallinity. The high GT waxy starches WM and RD4 retrograded to a greater extent measured with DSC and the order of increased retrogradation agreed well with the order of X-ray crystallinity of the retrograded waxy starches. The melting temperature (T_C) of the retrograded waxy starches in contrast to GT was very similar for all starches. This indicates that the temperature of the glass transition (T_g) of the amorphous regions in the starch granules controlled the onset GT and perhaps also the extent of retrogradation. Addition of cetyl trimethyl ammonium bromide (CTAB) decreased the extent of retrogradation more than 45% compared to the melting enthalpy (ΔH_C) of the waxy starches without CTAB addition. The rice starch RD4 was most affected by the CTAB addition, and the WM starch the least. The viscoelastic behaviour in the temperature interval 25–90°C of 12%(w/w) gels differed between the waxy starches. The WB starch gels showed the highest storage modulus (G′) value and the lowest phase angle (δ), i. e. strongest and least viscous gels. The WM starch gels showed the lowest G′ value and the highest δ. The rice starches were in between with the RC4 starch (high GT) showing higher G′ value and lower δ than the IR29 (low GT). The viscoelastic parameters changed only slightly with increased temperature. The addition of CTAB to the waxy starch gels changed the viscoelastic behaviour of the stronger and less viscous starch gels of the WB and RD4 as their G′ value decreased and δ increased with increased temperature. The effect on WM and IR29 was only small.     

Pasting Properties of Various Retrograded Starches Isolated with Ethanol

The pasting properties of various retrograded starches were studied by means of RVA. Most retrograded starch pastes showed a low‐temperature peak which did not appear in the viscograms of any raw starch sample: for wheat and rice starches, both a high‐temperature peak shown in the viscogram of their raw samples and a low‐temperature peak appeared, while for other cereal starches and potato starch, only a low‐temperature peak was detected in the retrograded paste. The low‐temperature peak began to appear, when the degree of gelatinization decreased below 60—70%. The viscosity of both peaks tended to increase to a maximum value and then decrease during storage.     

灌浆期糯米淀粉精细结构变化

分别对灌浆期11、13、15、17、22、27和35 d糯稻米取样,研究其淀粉形态、晶体和分子结构,揭示糯稻米成熟过程中淀粉精细结构的变化规律,以期为筛选慢消化性、抗老化性等新型糯米淀粉食品的加工原料提供科学依据。扫描电镜(SEM)和激光粒度仪(LPSA)研究结果表明,灌浆期糯米淀粉中出现球形颗粒,随着淀粉成熟,逐渐转化成为多面体状的颗粒,且颗粒峰值粒径不断增大,由5.92μm增加至6.77μm。X-射线衍射图谱(XRD)研究显示,灌浆期糯米淀粉晶型不变,然而淀粉晶体结晶度从31.0%增加至37.5%。采用阴离子色谱(HPLC-AEC)、高效尺寸排阻色谱联合多角度激光检测器与示差检测器联用系统(HPSEC-RID-MALLS)对样品分子结构进行检测发现,灌浆期淀粉分支密度逐渐增加,由81.91%提高至83.88%;灌浆后期大分子淀粉分子含量增加,相对分子质量6.817×10~7～1.033×10~8;灌浆后期糯米淀粉在水中更容易聚集。     

不同糯性谷物淀粉性质的比较研究

本研究选取圆糯米、血糯米、糯小麦、糯玉米、糯小米(糜子)、糯高梁和糯薏米为原料提取淀粉,比较研究了7种糯性谷物淀粉的性质,为其应用提供一定的参考。结果表明:透光率以糯玉米和糯高粱淀粉最大,为20%左右;糯薏米和糯小麦淀粉较易凝沉;50℃下圆糯米、血糯米和糯玉米淀粉的膨胀势较大;圆糯米淀粉的冻融稳定性最差,而糯小麦、糯玉米、糯小米(糜子)和糯高粱淀粉的较好;糊化温度以糯小米(糜子)淀粉最大,为67.8℃,而圆糯米、血糯米和糯玉米淀粉的糊化温度最小,均为60℃;7种糯性谷物淀粉的峰值粘度、保持粘度和最终粘度以糯小麦、糯高粱和糯薏米淀粉的最大,糯玉米淀粉的最小;由回升值/峰值粘度的大小可知,糯玉米淀粉最不易老化,糯薏米淀粉最易老化;糯高粱、糯小麦和糯薏米淀粉的抗剪切作用较弱,而血糯米和糯玉米淀粉在剪切过后有变稠的趋势。     

Gelatinization and Pasting Properties of Waxy and Non‐waxy Rice Starches

Gelatinization and pasting properties of diverse rice types grown in two locations were examined by differential scanning calorimetry (DSC) and rotational rheometry, respectively. The data were compared to previously reported molecular starch properties for these samples: specifically, amylose content, starch molecular weight (M_w), and amylopectin side‐chain‐length distributions. Significant correlations were observed between amylose content, starch M_w, and the weight degree of polymerization of the long side chains of amylopectin F₁(DP_w) and many of the gelatinization and pasting properties measured. Higher amylose content corresponded with increased gelatinization onset (T_o) and peak temperatures (T_p), pasting onset and peak temperatures, and decreased peak and trough viscosity. Starch M_w correlated negatively with T_o, T_p, pasting onset, and peak temperature and positively with peak, trough, final, and breakdown viscosity. Amylopectin with DP_w 59‐78 of F₁(DP_w) correlated with increased T_o, T_p, pasting onset and peak temperature, and decreased peak, trough, final and breakdown viscosity. Pasting properties were also somewhat related to DP_w 21 of shorter side chains of amylopectin (F₂(DP_w)). Significant correlations between F₂(DP_w) and peak, final, and breakdown viscosity were observed (r = −0.447*, −0.391*, −0.388*, peak, final, and breakdown viscosity, respectively).     

乙醇对丝素蛋白结构及功能特性的影响

为了研究在乙醇存在及不同透析时间下丝素蛋白的结构及功能特性,通过扫描电镜(SEM)、傅立叶红外光谱(FT-IR)、表面张力、乳化性、乳化稳定性、起泡性、起泡稳定性及蛋白溶解性进行测定。FT-IR分析表明当溶剂中添加乙醇后,样品中β-折叠结构明显增加。SEM分析表明Ca Cl2-CH3CH2OH-H2O体系处理的丝素蛋白较Ca Cl2-H2O体系溶解更为完全。随透析时间的延长,Ca Cl2-CH3CH2OH-H2O体系处理的丝素蛋白的最低表面张力值和临界胶束浓度均低于Ca Cl2-H2O体系。此外,Ca Cl2-CH3CH2OH-H2O体系处理的丝素蛋白液在透析20 h左右的乳化性最好,约为97.51%,15 h左右乳化稳定性最好,起泡性约为355.49%,泡沫稳定性在10 h左右最好;而Ca Cl2-H2O体系处理的丝素蛋白液在透析25 h左右乳化性最好,约为96.23%,20 h左右的乳化稳定性最好,起泡性约为200.86%,泡沫稳定性在15 h左右最好。因此,乙醇的加入可有效改善丝素蛋白结构和功能特性,为丝蛋白质基表面活性剂的开发提供理论依据。     

The Fine Structure of Corn Starches of Various Amylose-Percentage: Waxy,Normal and Amylomaize

The fine structure of high-amylose corn starches has been studied after dispersion of the starch and fractionation into their components amylose and amylopectin. The resulting amylopectin fraction reported in the literature possesses anomalous properties with regard to the waxy and normal amylopectin. However, the experimental results obtained by different authors for determining the structure lead to controversal explanations. Therefore, using an enzymic method, which permits the direct examination of the constitutive chains of the starch, the fine structure of the amylopectin of an amylomaize starch (64% amylose) has been investigated and compared with those of waxy and normal starches. The pullulanase – debranched chains are fractionated by gel permeation and their linearity are checked under the action of β-amylase. The inner chains of the amylopectin fraction are studied after debranching of the β-limit dextrins. The results show the identity between amylopectins from waxy and normal starches. The amylopectin fraction of amylomaize has its own structure with longer inner chains than those of waxy-maize amylopectin.     

Modeling Selected Properties of Extruded Waxy Maize Cross-Linked Starches with Neural Networks

ABSTRACT: Extrusion process is described as a complex multiple input, multiple output system. Various cross-linked waxy maize starches were extruded at initial moisture contents of 20, 24, and 28% (dry basis) and screw speeds of 110, 150, and 190 rpm. Multiple Input, Single Output neural network models were developed for predicting individual product properties, and Multiple Input, Multiple Output models were developed for predicting selected product properties at 1 time from selected input process parameters. Models varied only in the number of hidden neurons, ranging between 8 and 14. Models had R2 values of 0.89 and greater. Models explained the process and the influence of selected process parameters on selected product properties.