几种淀粉的糊化特性及力学稳定性(简报)

为探索淀粉糊化的力学稳定性,以不同来源淀粉为原料,采用快速黏度分析仪于不同搅拌速度下,研究外力作用对淀粉糊化特性的影响,为淀粉质食品的品质控制提供依据。结果表明,不同来源淀粉的黏度曲线及其力学稳定性有差异。以小麦淀粉的糊化温度最低;马铃薯淀粉糊的黏度和温度稳定性最大;马铃薯和莲子淀粉的峰值黏度较高,冷糊稳定性好;莲子淀粉的热糊稳定性差;玉米淀粉糊易于老化。外力作用对淀粉糊的黏度曲线有影响。较强的外力作用后,会导致淀粉糊的强度、黏度和糊化温度降低,改善热糊稳定性和冷糊稳定性。淀粉糊化的力学稳定性与其颗粒强度有关,较大颗粒强度的淀粉的力学稳定性较好。     

超高压处理对太白葛根淀粉理化特性的影响

采用超高压技术对太白葛根淀粉进行处理，研究超高压处理对太白葛根淀粉理化特性的影响。试验结果表明，超高压处理对太白葛根淀粉的颗粒大小和形态没有明显影响。超高压处理可使太白葛根淀粉糊的透明度明显增大，淀粉糊的冻融稳定性降低，提高太白葛根淀粉糊黏度对pH值的稳定性，但对其糊化黏度特性的影响不明显。300 MPa高压处理可改善太白葛根淀粉的理化特性。     

振动式超微粉碎处理时间对绿豆淀粉理化性质的影响

为研究振动式超微粉碎处理时间对绿豆淀粉理化性质的影响,提高淀粉类制品中抗性淀粉的含量,该文以绿豆淀粉为研究对象,通过振动式超微粉碎处理,研究了处理时间对样品的粒度分布、结晶度、溶解度、膨润力、凝沉性、老化值及提高抗性淀粉形成等性质的影响。研究结果表明:随着振动式超微粉碎处理时间的延长,绿豆淀粉颗粒的平均粒径、中位径(D50)和粒径分布的离散度增大,比表面积总体呈下降趋势;淀粉晶体的有序化程度降低,无定形化程度逐渐增强;在同一温度下,样品的溶解度大幅增加,同一处理时间的绿豆淀粉其溶解度随着温度的升高不断增加,低温膨润力随处理的时间延长而增加,高温膨润力随处理的时间延长而降低,且随着处理时间的延长,温度对膨润力的影响逐渐减小;绿豆淀粉糊的凝沉程度变高、凝沉速度变快,超微处理20 min可明显提高绿豆淀粉的老化程度,对提高抗性淀粉的形成具有促进作用,该研究为绿豆抗性淀粉的生产、提高绿豆淀粉制品中抗性淀粉含量的工艺改进提供了理论依据及技术支撑。     

马铃薯交联淀粉醋酸酯的制备工艺及特性

马铃薯原淀粉在水相体系、碱性条件下与醋酸酐作用，生成马铃薯淀粉醋酸酯，然后与交联剂进行交联反应，得到马铃薯交联淀粉醋酸酯。通过改变反应温度、反应时间、pH值和交联剂用量等条件，得出制取马铃薯交联淀粉醋酸酯的最佳工艺条件：反应温度35℃，pH值11，反应时间2 h，交联剂用量2%。所制取的马铃薯交联淀粉醋酸酯较原淀粉在糊液黏度的稳定性、抗老化性、抗分离性等方面均有较大的改善。     

60Co-γ射线辐照处理后马铃薯淀粉糊的流变特性

为深入了解辐照处理对淀粉糊流变特性的影响,采用60Co-γ射线对马铃薯淀粉进行0～400 kGy辐照处理后制成淀粉糊,使用流变仪研究了不同剂量处理辐照后马铃薯淀粉糊的流变特性。静态流变特性测定结果表明,不同辐照剂量处理后马铃薯淀粉糊均呈假塑性流体特征,符合幂定律;辐照剂量越大,马铃薯淀粉糊的表观黏度和剪切稀化程度越低,并逐渐偏近牛顿流体。动态流变特性测定结果表明,马铃薯淀粉糊的弹性模量峰值及其相应的峰值系统温度和20℃弹性模量均随辐照剂量的增加而降低。研究结果可为辐照处理后淀粉的应用提供基础数据。     

60Co-γ射线辐照处理后马铃薯淀粉糊的流变特生

为深入了解辐照处理对淀粉糊流变特性的影响,采用60Co-γ射线对马铃薯淀粉进行0～400 kGy辐照处理后制成淀粉糊,使用流变仪研究了不同剂量处理辐照后马铃薯淀粉糊的流变特性.静态流变特性测定结果表明,不同辐照剂量处理后马铃薯淀粉糊均呈假塑性流体特征,符合幂定律;辐照剂量越大,马铃薯淀粉糊的表观黏度和剪切稀化程度越低,并逐渐偏近牛顿流体.动态流变特性测定结果表明,马铃薯淀粉糊的弹性模量峰值及其相应的峰值系统温度和20℃弹性模量均随辐照剂量的增加而降低.研究结果可为辐照处理后淀粉的应用提供基础数据.     

甘薯淀粉糊与绿豆淀粉糊流变行为的共性与区别

淀粉糊在粉丝加工中作为黏结剂，它的流变特性是粉团搅拌、形成、漏粉和定型的关键因素。本研究通过对甘薯淀粉糊和绿豆淀粉糊在不同浓度、温度、剪切速率和升温扫描过程中的流变行为的考察和分析比较，表明两种淀粉糊有触变共性，在流变曲线图上都呈现出不同滞后面积大小的开口型滞后回路，用Cross方程拟合精度比幂律方程高；用Arrhenius方程描述两者都具有温度敏感性。两者的区别在于：甘薯淀粉糊在各条件下的滞后面积比绿豆淀粉糊小，说明在粉团形成中甘薯淀粉糊的持续增黏效果高于绿豆淀粉糊；虽然绿豆淀粉糊的零剪切黏度值比甘薯淀粉糊要低，但在浓度较低(≤8%)时，两者差别不大，因此用甘薯淀粉糊替代绿豆淀粉糊是可行的。     

基于岭脊分析的藜麦淀粉提取及糊化特性研究

为优化藜麦淀粉碱法提取工艺,以藜麦为试验材料,采用岭脊分析法研究料液比、NaOH 质量分数和浸提时间对淀粉提取率的影响,并对藜麦淀粉的颗粒形貌、化学结构及淀粉糊化特性进行研究。结果表明,碱法提取藜麦淀粉的优化工艺参数为料液比1：5 g/mL、NaOH质量分数0.2%和浸提时间5.5 h,淀粉提取率为98.94%±0.26%;藜麦淀粉为限制性膨胀淀粉,形态多呈不规则形,具有-OH、-CH2、-CHO、C-O-C和吡喃环典型淀粉分子官能团;随静置时间增加,淀粉透光率降低,凝沉体积增加,12 h后基本稳定;藜麦淀粉糊第四次冻融循环后达到稳定状态;对淀粉凝胶质构特性分析,硬度、内聚性、弹性、胶黏性和咀嚼性5个指标都随藜麦淀粉糊浓度增加而增大;流变性分析表明藜麦淀粉糊为假塑性流体,其弹性优于黏性。该文系统研究藜麦淀粉提取工艺和糊化特性,拓展了新的淀粉资源,同时也为藜麦淀粉的生产和应用提供一定的借鉴和参考。     

红花甜荞籽粒淀粉的理化特性

为明确红花甜荞籽粒淀粉理化特性,选用12个红花甜荞品种为材料,分析了其淀粉颗粒形态、粒度分布特征、直链淀粉含量、溶解度、透明度及糊化特性以及品种间差异。结果表明,红花甜荞淀粉颗粒多为不规则多角形和球形,多角形多且颗粒较大,球形颗粒较少且颗粒小,淀粉粒径范围介于0.38～25.78 μm;品种间淀粉粒径、直链淀粉含量、溶解度、透明度存在显著性差异（P＜0.05）;起始糊化温度在62.80～72.60℃,峰值黏度在126.58～141.00 RU;品种间谷值黏度、最终黏度、破损值、回生值和峰值时间差异显著。定边甜荞谷值黏度大,为118.00 RU;破损值及回生值小,分别为13.00和57.33 RU;达到峰值时间最长,达5.80 min;淀粉糊稳定性好。因此,在进行优质专用品种选育和产品加工时,应根据不同目标选择不同的甜荞品种。     

气流粉碎对玉米淀粉结构及理化性质的影响

为研究气流粉碎对玉米淀粉结构及理化性质的影响,该文以普通玉米淀粉为原料,通过流化床气流粉碎处理,采用扫描电子显微镜、偏光显微镜、粒度分析仪、X-射线衍射仪、红外光谱仪、差示扫描量热仪、快速黏度分析仪等分析手段研究经微细化处理前后玉米淀粉颗粒形貌、晶体结构、热力学特性、糊化特性、溶解度和膨胀度、冻融稳定性、持水能力等结构及性质的变化。结果表明,微细化处理后,淀粉颗粒形变的不规则,粒径明显减小,中位径(D50)由14.37μm减小到5.25μm,偏光十字减少,相对结晶度由33.43%降低至15.46%,淀粉颗粒结晶结构被破坏,由多晶态向无定形态转变,粉碎过程淀粉无新的基团产生;热焓值、糊化温度均降低,热糊稳定性好;溶解度、膨胀度均升高,持水能力增加,冻融稳定性好,产生较好的热糊稳定性和冷糊力学稳定性,该研究为玉米淀粉的深度加工与应用提供了理论依据及技术支撑。     

Effect of Dry Heating with Ionic Gums at Controlled pH on Starch Paste Viscosity

Waxy maize and potato starches were dispersed in pH 6.0 and 8.0 aqueous solutions (1%) of an ionic gum (sodium alginate, sodium carboxymethylcellulose, and xanthan). The mixture was dried at 45°C overnight and then heat‐treated 2 hr at 130°C. Effects on the paste viscosity of the products in a pH 7.0 buffer were examined. Heating with sodium alginate or sodium carboxymethylcellulose (CMC) increased the paste viscosity of waxy maize starch but reduced that of potato starch. In both starches, xanthan effected greater viscogram changes than did sodium alginate or CMC. Use of xanthan in the treatment produced products with restricted granular swelling and increased shear stability of the pastes. The pH of the starch‐gum mixtures affected the thermally induced viscosity changes. Mild acidity (pH 6.0) effected a viscosity decrease for the heat‐treated starch product, whereas alkalinity (pH 8.0) raised the viscosity regardless of the presence of gum. But pH 6 before heat treatment was favored for viscosity increase by sodium alginate, whereas pH 8 gave a greater increase in viscosity when xanthan was used. By using gum mixtures such as xanthan‐alginate and xanthan‐CMC, both viscosity increase and good shear‐stability were achieved.     

Effect of Oil Content and pH on the Physicochemical Properties of Corn Starch‐Soybean Oil Composites

Starch‐lipid composites are a new category of fat replacers. The physicochemical properties of reconstituted corn starch and soybean oil composites (CSSBOC) were evaluated and compared with the properties of reconstituted jet‐cooked corn starch (JCCS). Gel firmness, thermal properties, and hot pasting properties at two pH levels and two oil content levels were studied. Amylose content of CSSBOC was unaffected by processing. Buffer pH significantly affected the firmness of the gels made with JCCS. Gels appeared to have a more ordered structure and were firmer at pH 3.4 than at pH 6.0. The firmness of gels made with CSSBOC was not affected by pH or oil content. Retrogradation enthalpy of the gels made with JCCS was significantly affected by pH. Differences in the thermal characteristics of gels made with CSSBOC were attributed to pH and oil content. Peak viscosity, cold paste viscosity, and breakdown viscosity changed significantly when CSSBOC pastes were reconstituted in different pH buffers. Only hot paste viscosity and cold paste viscosity changed significantly when JCCS pastes were reconstituted in different pH buffers. Results establish critical parameters for processing decisions and for the understanding of the behavior of CSSBOC in food system models in which pH is an important factor.     

Effect of Ferulic Acid and Catechin on Sorghum and Maize Starch Pasting Properties

The effects of ferulic acid and catechin on starch pasting properties were studied as part of an investigation into the structure and functionality of phenolics in starch‐based products. Commercial maize starch, starches from sorghum cultivars (SV2, Chirimaugute, and DC‐75), and the phenolic compounds ferulic acid and catechin were used in the investigation. Pasting properties were measured using rapid viscosity analysis. Ferulic acid and catechin (up to 100 mg each) were added to maize or sorghum starch (3 g, 14% mb) in suspensions containing 10.32% dry solid content. Addition of catechin resulted in pink‐colored pastes, whereas ferulic acid had no effect on paste color. Ferulic acid and catechin decreased hot paste viscosity (HPV), final viscosity, and setback viscosity of maize and sorghum starch pastes, but had no influence on the peak viscosity (PV) of the former. Both phenolics increased breakdown viscosity. Ferulic acid had greater influence on HPV, final viscosity, breakdown, and setback than catechin. Addition of catechin under acidic conditions (pH 3) decreased HPV, final viscosity, and setback of maize starch, but alkaline conditions (pH 11) slightly increased setback. Both acidic and alkaline conditions resulted in increased breakdown. Investigations on model‐system interactions between ferulic acid or catechin and starch demonstrated that phenolic type and pH level both significantly influence starch pasting properties, with ferulic acid producing a more pronounced effect than catechin. The significance of these interactions is important, especially in food matrices where phenolics are to be added as functional food ingredients.     

Method for Determining the Rate and Extent of Accelerated Starch Retrogradation

A method to accelerate and quantitate retrogradation of starch pastes using a freeze-thaw cycle (FTC) process and turbidometric analysis has been developed. Using this method and differential scanning calorimetry (DSC), it was determined that the rate of retrogradation in 2.5% waxy maize pastes was inversely correlated to the rate of freezing, and that the thawing temperature affected perfection of the crystallites in retrograded amylopectin. DSC and X-ray diffraction were used to determine whether the crystallites formed during the FTC process were the same as those formed in starch pastes held isothermally at 4°C. Analysis of retrogradation of pastes of starches from various botanical sources indicated that the method reflects retrogradation in higher concentration pastes. Retrogradation rates were reduced by the addition of sodium dodecyl sulfate. Microstructures of freeze-thaw processed waxy maize and common corn starch pastes were examined.     

Genetic variation in the physical properties of sweet potato starch.

Sweet potato starch, prepared from 44 genotypes adapted to Philippine conditions, showed wide variation and distinctly different pasting profiles in Rapid Visco-Analyzer (RVA) analysis at 11% and 7% starch concentration. At 11% starch concentration, the pasting profiles were type A, characterized by high to moderate peak with a major breakdown and low cold paste viscosity. At 7%, the pasting profile was generally type C, characterized by the absence of a distinct peak with none to very slight breakdown and high cold paste viscosity. However, differentiation among genotypes was better achieved from RVA pasting profiles at 11% starch concentration. Peak viscosity (PV) and hot paste viscosity (HPV) at 11% starch paste concentration had significant negative correlation with amylose content. PV, HPV, and setback ratio were significantly correlated to adhesiveness of the starch gel. Sweet potato starch generally had high swelling volume but low solubilities at 92.5 degrees C.     

玉米淀粉与黄原胶复配体系流变和凝胶特性分析

为考察胶体对淀粉流变及凝胶特性的影响,该文以玉米淀粉为原料,加入不同比例黄原胶,研究两者复配后流变及凝胶特性的变化,对其相互作用机理进行了初步探讨。结果表明,玉米淀粉及两者复配体系属于屈服-假塑性流体,随着黄原胶比例的提高,复配体系的稠度系数显著增加,流体指数降低,假塑性增强,但黄原胶比例大于10%时,增加不再显著。动态流变学试验显示,复配体系具有更为优越的黏弹性,黄原胶可与淀粉分子间相互作用形成氢键,使得分子链段间的缠结点增加,同时,可延缓及阻止部分直链淀粉分子间的重新排列,从而抑制淀粉凝胶体系的回生,复配体系形成了质地更为柔软的凝胶。综合考虑,在实际应用中选择玉米淀粉与黄原胶质量比为9.0∶1.0 g/g较为适宜。研究结果可为更好的在食品工业中应用玉米淀粉/黄原胶复配体系及品质控制提供参考。     

Structures of Four Waxy Rice Starches in Relation to Thermal,Pasting, and Textural Properties

Waxy rice starches from three japonica cultivars (Taichung Waxy 1 [TCW1], Taichung Waxy 70 [TCW70], Tachimemochi) and one indica cultivar (Tainung Sen Waxy 2 [TNSW2]) were characterized for chemical and physicochemical properties. The amylopectin structures were different for the four waxy rice starches in terms of degree of polymerization (DP), average chain length (CL), exterior chain lengths (ECL), and distribution of chains, indicating the existence of varietal differences. The order of swelling power was TCW1 > TCW70 > TNSW2 > Tachimemochi; the order of water solubility index was TCW70 > TNSW2 > Tachimemochi > TCW1. The low water solubility index of TCW1 might be ascribed to a high DP. All starches shared similar gelatinization temperatures and enthalpies but showed distinct retrogradation patterns. TNSW2 showed the highest retrogradation rate, followed by TCW2, Tachimemochi, and TCW70. TCW70 exhibited the highest overall pasting viscosity, followed by TNSW2, TCW1, and Tachimemochi. The hardness of waxy rice starch pastes from a Brabender amyloviscograph increased rapidly after storage at 5°C for one day and remained the same or slightly increased after seven days of storage, whereas the opposite trend was observed for adhesiveness. The lower degree of retrogradation of TCW70 was probably a result of a larger amount of A chain and a shorter ECL. The changes in hardness correlated with the amount of A and B1 chains. The texture attributes of waxy rice starch pastes were significantly affected by amylopectin retrogradation during storage.     

Genetic Diversity in Physical Properties of Starch from a World Collection of Amaranthus

Physical and functional properties of starches isolated from 93 noncultivated genotypes of nine Amaranthus species from a world germ plasm collection and an additional 31 cultivated Amaranthus genotypes obtained from China were tested. A wide variation was found in the properties tested among the Amaranthus species and among genotypes within the same species. When comparing starches from cultivated and noncultivated genotypes, it was generally found that amylose was lower; starch pasting profiles were more consistent with higher peak viscosity, lower breakdown, and lower setback; the gelatinization temperature was lower; and energy of enthalpy was higher. Under cool storage, the hardness of cultivated starch pastes was lower and the adhesiveness was higher. As expected, amylose content was a primary factor affecting the physical and functional properties of Amaranthus starch. Compared with reference maize, rice, and wheat starches, Amaranthus starch tended to have lower hot paste viscosity and lower cool paste viscosity; and higher gelatinization temperatures and higher energy of enthalpy. Furthermore, Amaranthus starch pastes showed less change of gel hardness and adhesiveness after cold storage. The environmental effect on the different properties of starch varied among Amaranthus species. It is suggested that Amaranthus starches can be developed for a wide range of food uses.     

玉米淀粉与黄原胶复配体系流变和凝胶特性分析

为考察胶体对淀粉流变及凝胶特性的影响,该文以玉米淀粉为原料,加入不同比例黄原胶,研究两者复配后流变及凝胶特性的变化,对其相互作用机理进行了初步探讨。结果表明,玉米淀粉及两者复配体系属于屈服-假塑性流体,随着黄原胶比例的提高,复配体系的稠度系数显著增加,流体指数降低,假塑性增强,但黄原胶比例大于10%时,增加不再显著。动态流变学试验显示,复配体系具有更为优越的黏弹性,黄原胶可与淀粉分子间相互作用形成氢键,使得分子链段间的缠结点增加,同时,可延缓及阻止部分直链淀粉分子间的重新排列,从而抑制淀粉凝胶体系的回生,复配体系形成了质地更为柔软的凝胶。综合考虑,在实际应用中选择玉米淀粉与黄原胶质量比为9.0∶1.0 (g/g)较为适宜。研究结果可为更好的在食品工业中应用玉米淀粉/黄原胶复配体系及品质控制提供理论依据。