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.     

酸解对不同链/支比含量玉米淀粉特性的影响

以4种不同链/支比含量的玉米淀粉为原料,酸解处理不同时间,以酸解玉米淀粉的形貌特性、冻融稳定性、膨胀度、溶解度、晶体性质为指标衡量不同酸解时间对玉米淀粉结构性质的影响。结果表明:4种玉米淀粉酸水解程度的顺序为:蜡质玉米普通玉米淀粉G50G80。酸解后,同品种的4种玉米淀粉的析水率随着酸解天数的增加而增加;溶解度增加,膨胀度降低。酸解并未改变淀粉的晶型,随着酸解时间的延长,蜡质玉米淀粉和普通玉米的相对结晶度先增大后保持不变,G50和G80的相对结晶度随着酸解时间的增加而增大。表明酸解对低直链淀粉(蜡质玉米淀粉和普通玉米淀粉)的结构、性能影响最大。     

中强电场对α-淀粉酶水解玉米淀粉的影响

本文旨在利用中强电场强化α-淀粉酶催化的玉米淀粉水解。以还原糖含量为指标,考察电场强度、频率、缓冲液浓度、酶液比等因素对淀粉酶解效率的影响,并利用扫描电子显微镜、X射线衍射仪、差示扫描量热仪和热重分析仪表征酶解产物的结构和热性质。结果表明,电场强度、缓冲液浓度和酶液比显著影响淀粉酶解效率,但电场频率的影响不明显。当电场强度低于5 V/cm时,淀粉的酶解程度较小,酶解产物保持淀粉原有的颗粒和结晶结构,淀粉热稳定性略有降低;但随着电场强度的进一步增加,淀粉水解程度加剧,淀粉颗粒发生破裂、结晶峰逐渐消失、相对结晶度降低,糊化温度先增加后降低、热稳定性显著降低。     

A Study of Some Physicochemical Properties of High‐Crystalline Tapioca Starch

Tapioca starch was partially hydrolyzed in hydrochloric acid solution at room temperature for various lengths of time to obtain high‐crystalline starches. RVA viscoamylograms of acid‐modified starches demonstrated a very low viscosity as compared to that of native tapioca starch. The relative crystallinity of native and acid‐modified tapioca starches were measured by X‐ray diffraction ranging from 39.53% to 57.75%. The native and acid‐modified tapioca starches were compressed into tablets using various compression forces. The % relative crystallinity of starch increased with the increase in hydrolysis time and the crushing strength of the tablet was also increased in line with the crystallinity while the amylose content decreased when the crystallinity increased. These results suggested that the erosion of amylose might cause the rearrangement of starch structure into a new more tightly packed form, which provided the higher crushing strength for the tablets.     

Comparative Studies on Some Physico-chemical, Thermal, Morphological, and Pasting Properties of Acid-thinned Jicama and Maize Starches

Comparative studies on acid hydrolysis of jicama and maize starch were carried out using concentrations of hydrochloric acid of 1.5%, 3.0%, and 4.5% (w/v), for 3 and 6 h, at 40°C. Native maize and jicama starches showed important morphological, thermal, and structural differences from those of tubers and cereals which potentially offer diverse industrial applications. Jicama starch showed low amylose content (12%) and small size of starch granules. Due to these characteristics, jicama starch was more susceptible to degradation during hydrolysis process than maize starch. Under the experimental conditions employed, the acid degradation was not particularly severe, as shown by scanning electronic microscopy analysis which showed small degraded zones and similar X-ray patterns in both starches. However, jicama starch was more susceptible to acid hydrolysis than maize starch, as revealed by the considerable increase in water solubility index, damaged starch, and crystallinity values. Also, the higher susceptibility of jicama starch than maize starch to the hydrolysis conditions was reflected in the sugar content release during hydrolysis. The relative crystallinity of hydrolyzed maize starches decreased during hydrolysis, while those of hydrolyzed jicama starches increased attributable to the lower amylose content of jicama starch in relation to maize starch. Maize and jicama hydrolyzed starches showed low viscosity values with relation to their native starch counterparts. However, native jicama starch showed lower viscosity values than maize starch, suggesting a lower internal stability of the starch granules during hydrolysis. Both native and hydrolyzed maize starches showed higher enthalpy, T _o, T _p, and T _c values than jicama starch and the broadening of the endotherms decreased during the hydrolysis of both starches.     

Microstructural Characterization of Plasticized Starch‐Based Films

Edible films were developed using different starch sources (corn starch and amylomaize). Starch suspensions were cold gelatinized with NaOH; either glycerol or sorbitol were used as plasticizer. Films were characterized by Differential Scanning Calorimetry (DSC), X‐ray diffraction, Scanning Electron Microscopy (SEM) and gas (CO₂ and O₂) permeabilities. SEM observations showed that plasticizer addition was necessary for film integrity. The evaluation of film formation by DSC indicated that cold gelatinization was the main factor of thermal transitions. Film crystallinity was analyzed by DSC and X‐ray diffraction during storage. For all tested formulations, film crystallinity increased while gas permeability decreased during storage. Films containing glycerol or sorbitol showed a lower crystalline/amorphous ratio by X‐ray diffraction and DSC than unplasticized films. Amylomaize films with higher crystalline/amorphous ratio gave lower gas permeabilities than the corresponding corn starch films; films containing sorbitol showed lower permeability values than those containing glycerol.     

亚糊化热处理对玉米淀粉-胡椒碱复合物功能特性的影响

为探究在亚糊化温度下胡椒碱负载于玉米淀粉对其结构和理化特性的影响,本研究选用玉米淀粉在60℃下制备亚糊化玉米淀粉-胡椒碱复合物,并通过扫描电镜、快速糊化粘度测定仪、差示扫描量热、傅里叶变换红外光谱和X射线衍射等进行了表征。结果表明,胡椒碱成功负载到亚糊化玉米淀粉上,负载率为39.45%;扫描电镜结果显示淀粉颗粒膨胀的裂隙内部成功负载胡椒碱,粒径从天然玉米淀粉的15.20μm增大到亚糊化玉米淀粉的25.80μm,再到亚糊化玉米淀粉-胡椒碱复合物的81.90μm;胡椒碱的加入降低了亚糊化玉米淀粉的峰值粘度和谷值粘度;复合物红外光谱未产生新的基团或化学键,但胡椒碱的加入增强了玉米淀粉与胡椒碱的分子内和分子间氢键作用;X-射线衍射表明相对结晶度从天然玉米淀粉的23.52%升高到亚糊化玉米淀粉-胡椒碱复合物的28.15%,但是亚糊化处理未改变玉米淀粉的晶型结构;与天然玉米淀粉相比,亚糊化玉米淀粉和亚糊化玉米淀粉-胡椒碱复合物的凝胶焓值显著（P<0.05）降低。亚糊化玉米淀粉负载胡椒碱,胡椒碱的加入对亚糊化玉米淀粉的结构影响较小,但对其理化性质产生了显著的影响,并为淀粉与胡椒碱之间的相互作用...     

玉米淀粉、籼米淀粉薄荷酮复合物的结构和释放性能的比较

采用共沉淀法制备玉米淀粉薄荷酮复合物及籼米淀粉薄荷酮复合物,并对2种淀粉复合物复合率进行测定,玉米淀粉薄荷酮复合物复合率为43.8%,籼米淀粉薄荷酮复合物复合率为24.7%。对2种淀粉复合物结构进行表征,通过CP-MAS13C NMR、XRD、红外及扫描电镜对复合物进行分析。核磁中新峰的出现及淀粉骨架的化学位移、XRD衍射新峰的出现及结晶度的变化及复合物形成前后表面形态的明显变化,证明了淀粉复合物的形成。利用Avrami方程对2种淀粉薄荷酮复合物在4、25℃,相对湿度33%、75%、90%条件下的释放情况进行分析,结果表明,低湿低温环境中贮藏的复合物更加稳定,且玉米淀粉薄荷酮复合物的贮藏稳定性高于籼米淀粉薄荷酮复合物。     

Effects of Annealing on ultra-high pressure induced gelatinization of corn starch

Ultra-high pressure (UHP) can induce starch gelatinization at the room temperature, while the change of starch architecture could affect the gelatinization process. This work evaluated the effects of annealing on UHP induced starch gelatinization. Native and annealed corn starches were subjected to UHP treatment (300–600 MPa) for 15 min at room temperature. The scanning electron microscopy, confocal laser scanning microscopy, differential scanning calorimetry and X-ray diffraction analysis showed that UHP treatment partially disrupted the ordered structures of native and annealed starches, which made starch gelatinized gradually and a transformation in crystal type from type A to type B. However, compared with native starch, annealing (C3 and C24) delayed the internal and external structure destruction of starch granules, as well as induced a slower decrease in ΔH and relative crystallinity as increasing pressure. Therefore, the suitable UHP treatment can increase the pressure resistance of starch, or delay the UHP gelatinization process.     

挤压剪切活化对添加耐高温α-淀粉酶脱胚玉米淀粉结构和理化特性的影响

本研究通过偏光显微镜、扫描电子显微镜、热台显微镜、X射线衍射、差示扫描量热分析、傅里叶变换红 外光谱分析等手段,研究原脱胚玉米、挤压脱胚玉米和添加耐高温α-淀粉酶挤压脱胚玉米的淀粉结构及性质变化, 并探究其相互关系,揭示挤压剪切活化对脱胚玉米的淀粉颗粒机械力化学效应。研究表明：与原脱胚玉米和挤压脱 胚玉米相比较,挤压处理对添加耐高温α-淀粉酶脱胚玉米的淀粉结构及性质产生显著影响,酶解力和糊化度增大,碘 蓝值、直链淀粉含量减小。添加耐高温α-淀粉酶挤压脱胚玉米淀粉颗粒形貌破坏,偏光十字破坏,结晶度变小;升温糊 化过程中,焓变降低;挤压使淀粉颗粒的结晶结构破坏,淀粉颗粒发生聚集,破损淀粉颗粒易糊化和裂解。     

干热处理辅助酶法制备多孔淀粉及其对淀粉微观结构和理化性质的影响

为了探讨干热处理对酶解制得多孔淀粉颗粒结构和理化性质的影响,采用扫描电子显微镜、傅里叶变换红外光谱仪、X射线衍射仪、比表面及空隙度测试仪、热重分析仪等对不同处理的淀粉进行测定,分析比较了干热处理(Dry heat treatment,DHT)对天然淀粉及多孔淀粉的影响。结果表明,经DHT的淀粉表面出现破损,相对结晶度减小;而经DHT制得的多孔淀粉颗粒表面孔洞数量增多,淀粉结晶度提高,耐热性增强;DHT提高了多孔淀粉的比表面积和总孔容,分别从1.16m2/g和21.22×10-3 cm3/g 增大至3.14m2/g和31.41×10-3 cm3/g,使得吸附能力增强。研究结果表明干热处理结合酶解可以改善多孔淀粉的性能。     

Characterization and Utilization of Acid‐modified Rice Starches for Use in Pharmaceutical Tablet Compression

Acid modified, agglomerated starches offer specific advantages as fillers in production of pharmaceutical tablets. Spray drying can improve processing of tablet mixtures significantly. In order to investigate prerequisites in utilization of rice starch, non‐waxy and waxy types were partially hydrolyzed in 6% (w/v) HCl solution at room temperature for varied length of time to obtain rice starches with increased crystallinity (so‐called crystalline rice starches). Scanning electron micrographs of native and highly crystalline starches were used to study the morphological changes and to suggest the mode of acid attack during hydrolysis. Exo‐corrosion distributed over the surface of acid‐modified waxy rice starch (AWRS) was observed after 192 h of hydrolysis. In contrast, the surface of acid‐modified rice starch (ARS) remained unchanged at 192 h of acid hydrolysis. The amylose content and the median particle size (diameter) were reduced with increasing hydrolysis time. It was found by X‐ray diffraction that the relative crystallinity of acid‐modified starches at >95% relative humidity was clearly increased with prolonged hydrolysis time. For studying tablet properties spherical agglomerates of the native and acid modified starches were directly compressed at 4 kN to obtain tablets. Crushing strength and disintegration time of tablets increased with relative crystallinity. In contrast, tablet friability was reduced. Concerning tablet functionality, the crystalline starches were positioned in overlapping ranges between the common commercial tablet fillers (microcrystalline cellulose, pregelatinized starch and lactose, respectively).     

蜡质玉米淀粉微晶的理化性质及其消化性研究

以蜡质玉米淀粉为原料,在酸醇介质中制备淀粉微晶。对制得的不同水解率的蜡质玉米淀粉微晶进行了颗粒形貌、X射线衍射、DSC热稳定性分析,溶解度和消化性能的测定。结果表明:随着酸醇水解程度的增加,淀粉颗粒形貌逐渐呈片晶状,最终为碎片;淀粉颗粒的无定形区先被水解,结晶区后被水解,进而导致颗粒破裂;晶体形态仍为A型。与原淀粉相比,淀粉微晶的Tp和Tc均增大,糊化温度范围也有很大提高;不同水解率的淀粉微晶的热焓(△H)先减小后增大。淀粉微晶的溶解度随水解率的增加不断增大。酸醇水解蜡质玉米淀粉的水解率越高,其在in vitro模型中的消化产物也就越多,消化速度也越快。对于同一水解率的淀粉微晶,其消化速度随时间的延长先上升后下降。     

Study on Relative Crystallinity of Moist Potato Starch

The relative crystallinity of various moist potato starches were measured by X-ray diffractometer. The diffraction patterns showed to become sharp with increasing of the amount of sorption moisture. Both areas of crystallinity portion were proportionally correlated with the amount of moisture. On the assumption that crystallinity of cellulose is 70%, that of native potato starch was showed to be 24%.     

酸解马铃薯淀粉-油酸复合物的制备

以酸解马铃薯淀粉和油酸为原料制备酸解马铃薯淀粉-油酸复合物,运用X-射线衍射(X-RD)技术探讨了淀粉酸解时间、原料配比和淀粉浓度对复合物结晶的影响.结果表明:酸解马铃薯淀粉-油酸复合物为V-型结构,随着酸解时间的延长和原料配比的增大,衍射峰的强度越来越大,复合物的结晶结构越来越完整,但相互之间结晶度变化不明显,当原料浓度为2%时,所形成的复合物的结晶度最高,约为82.23%.     

Ordered structure and thermal property of acid-modified high-amylose rice starch

High-amylose cereal starch has a great benefit on human health. Acid modification is very helpful for application of high-amylose starch in food and non-food industries. In this study, the ordered structure of acid-modified high-amylose rice starch was investigated by GPC, HPAEC, ¹³C CP/MAS NMR and XRD. Acid preferentially degraded the amylose, then A chain and short B chain of amylopectin. Relative double helix content and crystallinity both initially increased sharply and then progressively with acid hydrolysis. The relative crystallinity of starches obtained from ¹³C CP/MAS NMR was higher than that from XRD. The onset gelatinisation temperature decreased, while the peak and conclusion temperatures increased with increasing hydrolysis time. The endothermic value initially increased and then decreased with acid hydrolysis. The swelling power decreased while solubility increased after acid hydrolysis. These results add to our understanding of the effect of acid hydrolysis on the high-amylose rice starch.     

Preparation and Characterization of Annealed‐Enzymatically Hydrolyzed Tapioca Starch and the Utilization in Tableting

Tapioca starch was annealed at 60°C for 90 min followed by hydrolysis with α‐amylase at 60°C at various lengths of time (30, 60 and 120 min) to obtain high‐crystalline starches. The reaction products were subjected to spray drying to obtain annealed–enzymatically hydrolyzed–spray dried tapioca starch (SANET) in the form of spherical agglomerated granules. The properties of SANET were compared with those of annealed–spray dried tapioca starch without enzymatic treatment (SANT) and native–spray dried tapioca starch (SNT). Scanning electron micrographs of the starch samples were used to study the morphological changes and to suggest the mode of enzyme attack during hydrolysis. The á‐amylase preferentially attacked the interior of the starch granules, leaving a deep round hole on the starch granule surface. It was found by X‐ray diffraction that both annealing and amylolysis did not alter the A type diffraction pattern. The% relative crystallinity of SANET was raised with increasing hydrolysis time and with decreasing amylose content. High performance size exclusion chromatography (HPSEC) demonstrated the decrease of the degree of polymerization (DP) of the amylose fraction of SANET after prolonged hydrolysis. For the utilization of SANET as tablet filler, it was directly compressed by a tablet compression machine at 4 kN to obtain tablets. The increased relative crystallinity of starch resulted in increased crushing strength and disintegration time, but in a decreased tablet friability.     

Modification and properties of African yam bean (Sphenostylis stenocarpa Hochst. Ex A. Rich.) Harms starch I: Heat moisture treatments and annealing

African yam bean (Sphenostylis stenocarpa) starch was subjected to heat moisture treatments at 18% (HMT-18), 21% (HMT-21), 24% (HMT-24), 27% (HMT-27) and excess (Annealing) moisture levels. Proximate chemical composition of the starch samples revealed that the moisture content of the starches ranged between 6.7% and 12.5%. Following modification of the native starch, there was a reduction in the moisture level of the heat moisture treated starches from HMT-18 to HMT-27. However, the annealed starch (HMT-ANN) retained higher moisture content compared to native starch (AYB-Native). The carbohydrate, protein, ash, amylose and fat content reduced with all the forms of heat treatments. At the temperature range studied (60–90 °C), increasing level of heat moisture treatments reduced the solubility and swelling capacity. pH also exert a profound effect both on the solubility and the swelling of the starch. Increasing degree of alkalinity increased both solubility and swelling capacity. In the native and modified starch samples, replacement of the wheat flour by the starch resulted in increased alkaline water retention of the blends. Water absorption capacity of the starch increased with the severity of moisture treatments, while the oil absorption capacity decreased. Apart from HMT-18, there was improved gel forming capacity of all the other heat-modified starches.Pasting temperature increased after hydrothermal modifications, whereas peak viscosity (P_v), Hot Paste Viscosity (H_v), setback and breakdown values all reduced after heat moisture treatments. All the starches were of type-B viscosity.Differential scanning calorimetry studies revealed that heat moisture treatment shifted the onset temperature (T_o), peak temperature(T_p) and conclusion temperature (T_c) to higher values. The gelatinisation temperature of the annealed starch was comparable to native starch. In addition, gelatinisation band of the native starch increased progressively from HMT-18 to HMT-27. Heat moisture treatment reduced the gelatinsation enthalpy (ΔH), while the enthalpy of retrogradation(ΔH_r) increased with the storage time of the gelatinised starch. Retrogradation enthalpy of the heat moisture conditioned starches were lower than the value obtained for the native starch.X-ray diffraction studies of the starch indicated that all the starch samples showed the type-C diffraction pattern. Differences were however observed in their degree of crystallinity. Native starch exhibited the lowest crystallinity (20%) while annealed starch had the highest crystallinity (27%)Microscopy studies revealed surface indentation, formation of groves in the central region, folding of starch granules and formation of doughnut-like appearance in some of the starch samples.     

Physicochemical Properties of Non‐thermally Cross‐linked Corn Starch with Phosphorus Oxychloride using Ultra High Pressure (UHP)

Corn starch (20%, w/w) was non‐thermally and conventionally cross‐linked with phosphorus oxychloride (POCl₃; 0.01, 0.05, or 0.1%, based on dry weight of starch) at 400 MPa for 5, 15 and 30 min and at 45°C for 2 h, respectively. Swelling power and solubility of both non‐thermally and conventionally cross‐linked corn starches were relatively lower than those of native corn starch. The pressure holding time did not affect the solubility and swelling power of non‐thermally cross‐linked corn starches. X‐ray diffraction patterns and relative crystallinity were not significantly altered by both conventional and non‐thermal cross‐linking. DSC thermal characteristics of both non‐thermally and conventionally cross‐linked corn starches were not significantly changed indicating that the double helical structure of amylopectin was not influenced by both conventional and non‐thermal cross‐linking reactions. Both non‐thermal and conventional cross‐linking greatly affected the Rapid Visco Analyser (RVA) pasting properties, such as increase in pasting temperature and decrease in peak viscosity compared to native starch. This result suggests that in case of cross‐linking using POCl₃, both non‐thermal and conventional methods result in similar physicochemical properties and non‐thermal cross‐linking with POCl₃ can reduce the reaction time from 2 h to 15 min. This work shows the potential and possibility of non‐thermal starch modification and provides the basic and scientific information on the physicochemical properties of non‐thermally cross‐linked corn starches with phosphorus oxychloride using UHP.     

DMSO/H2O法制备高链玉米淀粉-脂肪酸包合物的热性质

采用差示扫描量热仪和热重分析仪研究脂肪酸的链长和不饱和度对高直链玉米淀粉-脂肪酸包合物热性质的影响,并利用X-射线衍射仪对其结晶结构进行了分析。研究表明,高直链玉米淀粉-脂肪酸包合物的复合指数、糊化焓值和相对结晶度均随着脂肪酸碳链长度和不饱和度的增加而减小。与高直链玉米淀粉相比,高直链玉米淀粉-脂肪酸包合物的糊化起始温度、峰值温度和终止温度随脂肪酸碳链长度的增加而升高,分别增加了23~27、26~29、27~29℃;包合物的玻璃化转变温度和最快反应速率对应的温度随不饱和度的增加而降低,下降了约0.3~1.0℃。淀粉与脂肪酸复合后晶型由B型变为V型。