Changes of Relative Crystallinity of Potato Starch Under Gamma Irradiation

Indices of relative crystallinity of starch samples after gamma irradiation in dry form or in potatoes have been determined by differential and integral methods and compared with those calculated for corresponding reference samples. In the case of dry samples, the diminution of relative crystallinity was observed after gamma ray irradiation. In the case of starch samples extracted from irradiated potatoes, the influence of drying conditions was additionally observed. The diminution of relative crystallinity seems to be accompanied by destruction of long-range ordering as observed by SAXS experiment.     

微波辐射对马铃薯淀粉结晶度和α度的影响

采用酶水解法、X-射线衍射法等研究了微波辐射对马铃薯淀粉的结晶度和α度的影响。试验结果表明：微波辐射可有效改变马铃薯淀粉的结晶度和α度，在微波辐射功率一定的条件下，马铃薯淀粉乳的浓度不同，经微波辐射后的样品结晶度和α度变化也不同，马铃薯淀粉乳的浓度与经微波辐射后样品的X-射线衍射图谱的晶峰面积及样品结晶度的大小呈正相关，与经微波辐射后Ⅸ度的高低呈反相关。     

变性淀粉结晶性和形态研究

利用光学显微镜和X射线衍射对玉米变性淀粉的颗粒形貌和结晶结构进行了研究和讨论，揭示出一定变性度下，不同的变性淀粉仍然具有球晶结构和结晶性，保持其刚性粒子特性。与原淀粉相比，变性淀粉的粒子形态未受到破坏。     

Effect of the Degree of Phosphorylation on the Crystallinity of Native Potato Starch

X-ray diffraction technique, combined with digital image processing was used to compare the crystallinity of native starch from a number of potato varieties, differing in the degree of phosphorylation. The crystallinity was found to decrease linearily with an increased degree of phosphorylation. Based on earlier observations of the gelatinization enthalpies, it was assumed that the C-6 phosphates, which have an orientation out of the α-helices disturb the crystallization of the amylopectin during the starch synthesis. The C-3 phosphates, which are located in the interior parts of the α-helices, are not believed to interfere with the crystal structure.     

Changes in Crystallinity and Gelatinization Phenomena of Potato Starch by Acid Treatment

The hydrolysis of potato starch by 1-N H₂SO₄/30% ethanol aqueous solution at 45°C increased linearly with increasing of hydrolysis time for 14 d. The relative crystallinity of native starch showed 0.343 and 0.350 by symmetrical reflection and transmission techniques, resp. The increasing ratio of relative crystallinity to hydrolysis time corresponded very closely with that of 1/hydrolysis residue up to 14 d. These facts suggest that only the amorphous region of the starch granules will be hydrolyzed by the acid. By differential scanning calorimetry the calorimetric enthalpy of potato starch containing about 200% moisture content was found to stay largely unchanged by acid treatment for 6 d. The swelling power at 70° and 80°C of potato starch reached to the minimum value and, moreover, from the gel-chromatogram patterns of the acid-treated starches, the crystalline region of the starch granules may begin to deteriorate slightly by acid treatment for more than 6 d, although the relative crystallinity by the X-ray diffraction method increased slightly with passing of hydrolysis time.     

蕉藕淀粉与薯类淀粉特性对比研究

为探索蕉藕淀粉应用范围,选取木薯淀粉、马铃薯淀粉、红薯淀粉等薯类淀粉为对照,对蕉藕淀粉与常见薯类淀粉的组成、吸水(油)率、溶解度、膨胀度、透明度、凝沉性、凝胶强度、冻融稳定性及黏度等特性进行了对比分析。结果显示:蕉藕淀粉与常见薯类淀粉特性相比除吸水性差异不显著外,吸油率、溶解度、膨胀度、透明度、凝沉性、凝胶强度、冻融稳定性及黏度变化均存在显著差异,可利用蕉藕淀粉直链淀粉含量高、透明度好、凝胶强度高等特性,开发新型淀粉食品和增稠稳定剂。     

Evolution of Crystallinity and Specific Gravity of Potato Starch versus Water Ad- and Desorption

Interrelation between water vapour sorption hysteresis on native potato starch and X-ray diffraction structure analysis has been investigated. The crystallinity appears to be significantly dependent on water content and is modified by the ad-sorption state. The dependence has been specifically studied for (100) reflexion intensity which increases largely and linearly with hydration and is constantly larger in desorption. The specific gravity measurements obtained by gas comparison and liquid pycnometry have shown significantly higher values in adsorption than in desorption. The facts presented here show the importance:

• – of water as a necessary compound for the building up of crystalline structure of B starch and
• – of the mobility of α-D -glucosidic chains to account for the hysteresis in all three properties studied when observed at equal water content.

     

直链结晶淀粉形成过程中结晶度的变化

以蜡质玉米淀粉为原料,采用酶法制备直链结晶淀粉,优化酶法制备直链结晶淀粉的工艺参数,通过斐林试剂法和X-射线衍射技术考察酶相对作用量及作用时间对直链结晶淀粉DE值、结晶度的影响。采用酶法所制备的直链结晶淀粉有可能形成一种新的材料,可部分或全部替代价格昂贵的微晶纤维素,应用于药用辅料及片剂制品工业中。     

红薯淀粉糖化条件的研究

对红薯中淀粉的糖化参数进行了研究。确定糖化温度、液化液pH值、糖化时间、用酶量等单因素范围．并进行了正交实验,以淀粉的水解程度（DE值）为指标选出最佳糖化参数。实验结果：最佳参数为糖化温度60℃左右,pH值4．0-4．5,糖化时间以48-60h为宜,用酶量为300U／g淀粉。     

甘薯淀粉增白方法的研究

提出了用氧化剂次氯酸钠与少量多偏磷酸钠混合氧化漂白甘薯淀粉的新方法，并从淀粉的化学结构和反应机理方面作了初步的探讨。氧化漂白后的淀粉通过ＳＢＤ－１型数字白度计测量，其白度达到８５．９，已超过目前市售的玉米淀粉与绿豆淀粉的白度。     

微细化马铃薯淀粉流变学特性的研究(一)

通过机械球磨对马铃薯淀粉进行粉磨，采用流变仪研究了马铃薯淀粉及其不同微细化程度产物的糊的流变特性。结果表明，所有淀粉样品糊均呈现假塑性流体特征。球磨时间越长的样品，其糊的表观粘度越低，越偏近牛顿流体，触变性和剪切稀化也越低。     

Molecular Depolymerization of Moist Sweet Potato Starch Melt by Shearing Force under an Elevated Temperature

Sweet potato starch (SPS) with 20 or 25% moisture was heated and then fused at 150°C for 15 min under pressurization at 30–500 Kg/cm². At the same time, the heated SPS melt was extruded through a capillary tube under specified pressure in order to give shearing force. Thus, intact SPS, heated SPS and heated sheared SPS specimen were prepared and examined. The heated and heated sheared SPS did not contain any pyrolysis products because their spectrum profiles were the same as that of intact SPS. By heating and shearing, the intact SPS molecule was depolymerized into small molecules including a few amount of glucose. This finding was revealed by means of molecular weight estimation by viscometry and by gel filtration. The shearing toward SPS melt markedly stimulated the depolymerization while the effect of only heating on depolymerization of SPS was modulate in comparison with heated shearing. Water solubilities of intact SPS, heated SPS and heated sheared SPS with 20% moisture were 0.07, 3.5 and 51.5% respectively, and also the degrees of gelatinization of 1.8% for intact starch increased markedly to 29% for heated SPS and 80–95% (depending on the pressure at extrusion) for heated sheared SPS.     

交联酯化甘薯淀粉特性研究

采用示差扫描量热仪(DSC)、扫描电子显微镜(SEM)和X-射线衍射仪(X-ray)研究了交联酯化甘薯淀粉的特性,结果表明,甘薯淀粉经过不同的交联酯化作用后,其糊化特性、颗粒形态外观特征和X-衍射图谱等发生明显的变化,并对其变化机理进行了分析。     

淀粉酶分解马铃薯淀粉的因素研究

研究α-淀粉酶与β-淀粉酶对马铃薯淀粉的分解效果。在控制一定温度和时间的条件下,采用正交设计、因素分析、优化处理、均衡试验。实验结果表明,α-淀粉酶添加量0.15%(4000U),淀粉量20%,处理温度80.0℃,时间13min,液化效果达到最佳;β-淀粉酶量0.15%(50000U)、温度60℃、时间46h、pH5.4,糖化效果最佳。     

Studies on the Relationship Between Water-satured State and Crystallinity by the Diffraction Method for Moistened Potato Starch

Crystallinity was measured by X-ray diffraction method and water-saturated state was determined by means of the moisture contents calculated from the crystallinity for moistened cellulose and potato starch. In the X-ray diffractograms the upper areas which were separated by the straight line joined the points of intensity at 37° and 4° (8°) of diffraction angle was the relative reflection area in the crystalline and amorphous portions, and the lower area was the background of the non-relative reflection area. The upper area separated by the smooth curve joined the minimum intensity at 4° to 37° of diffraction angle corresponded to the crystalline portion and the lower area to the amorphous one. The ratio of the crystalline portion to sum of the crystalline and amorphous portions was considered to be crystallinity. Crystallinity of the air-dried and the moisture-saturated (28%) samples of cellulose were 0.68 and 0.71, resp. The crystallinity of the air-dried and water-saturated (49%) samples of potato starch were 0.24 and 0.32, resp.     

Crystallinity of Acid Treated Corn Starch

The hydrolysis of corn starch by 1N H₂SO₄-30% ethanol aqueous solution at 45°C increased linearly with increasing of hydrolysis time for 20 d. The relative crystallinity of native corn starch showed 0.350 by X-ray diffraction and it increased gradually with increasing of hydrolysis time up to 8 d. The increasing ratio of 1/hydrolysis residue to hydrolysis time increased more largely than that of relative crystallinity after 14 d. On the other hand, the relative crystallinity of native corn starch by deuteration showed 0.341 very near to the value by X-ray diffraction. Moreover, this increasing ratio of the crystallinity accompanied by acid hydrolysis showed an inclination similar to that given by X-ray diffraction. These facts suggest that the exchanging of OH for OD groups may be caused very a little in crystalline region of corn starch granules.     

微细化马铃薯淀粉流变性质的研究

通过机械球磨对马铃薯淀粉进行粉磨，采用流变仪研究了不同条件下马铃薯淀粉及其不同微细化程度产物的糊的流变特性，结果表明，淀粉样品糊的流变性质随着浓度，温度因素的变化而有显著变化。     

马铃薯淀粉糊相对分子质量在超声场中的变化规律

为揭示超声场对淀粉相对分子质量的影响,以马铃薯淀粉糊为研究对象,采用凝胶渗透色谱仪测定了不同超声场条件与不同马铃薯淀粉糊质量浓度对马铃薯淀粉相对分子质量的影响。研究结果表明:马铃薯淀粉糊的数均相对分子质量、重均相对分子质量、峰均相对分子质量都有一定程度的降低,表明超声场中,淀粉分子发生降解,降解程度随作用时间的延长而增大,随超声强度的增大,淀粉分子进一步降解,但降解程度减小;淀粉糊的质量浓度越低受超声场的影响越大。超声作用时间对马铃薯淀粉糊相对分子质量分布宽度的影响规律是:初始阶段降解是一个随机过程,相对分子质量分布变宽;中间阶段转变为一个非随机过程,淀粉糊相对分子质量分布变窄;最后阶段相对分子质量分布趋于一个极限值。