Studies on Hydroxyethyl Starch. Part 3. The Preparation of 2-Hydroxyethyl Ethers of Glucose

Samples of 2-O-(2-hydroxyethyl)-D-glucose, 3-O-(2-hydroxyethyl)-D-glucose, and 6-O-(2-hydroxyethyl)-D-glucose were made by allowing glucose derivatives containing suitable blocking groups to react with 2-bromo-ethanol, followed by removal of the blocking groups.     

The Influence of Acid Hydrolysis of Potato Starch on the Stress-Strain Propoerties of Thermoplastic Starch

Potato starch has been hydrolysed lowering the molecular mass. The influence of starch molecules mass on the mechanical properties of thermoplastic starch has been investigated. Acid hydrolysis was performed with hydrochloric acid in various concentrations and time spans. Acid hydrolysis of the granular potato starch decreased both the molecular mass of amylose and amylopectin. The thermoplastic materials have been made by extrusion processing of the various starches with fixed amounts of water and glycerol. The stress-strain properties showed to be influenced by molecular mass. The materials were rubbery at 20°C and 60% relative humidity. Although the tensile stress did not change significantly, the elastic modulus increased with an decrease in molecular mass. This increase was explained by differences in starch structure and morphology. The higher of the low molecular mass materials could result in a more rapid starch structural ordering. The elongation and tearing energy increased with incrasing molecular mass. Theses effects were explained by the higher amylose chain length and amylopectin endgroups chain length resulting in a more entangled polymer matrix.     

Studies on the Biosynthesis of Starch Granules. Part 7. Compound Granules in Potato Starch

The nature of compound starch granules in potato starch is examined. The relevance of this investigation to the possible formation of potato starch is discussed, and a mechanism for synthesis of compound granules proposed.     

甘薯滨粉磷酸单酯在冰淇淋中的应用研究

对冰淇淋中常用稳定剂和甘薯淀粉磷酸单酯的流变特性进行了研究，同时通过对老化时间、粘度、膨胀率、融化率等方面的影响分析，探讨了甘薯淀粉磷酸单酯作为冰淇淋中的稳定剂和取代冰淇淋中部分油脂的可行性。研究结果表明，用甘薯淀粉磷酸单酯制造冰淇淋，可减少老化时间，降低融化率、抑制冰晶形成、降低产品脂肪含量，在口感、内在质地等诸方面均可为消费者接受，取得了较好的效果。     

The Characterization of Starch and its Components. Part 5. Observations on the Quantitative Acid Hydrolysis of Starch and Glycogen

A method and conditions are presented for the quantitative hydrolysis of starch to glucose by acid, in which no significant levels of acid-catalyzed reversion occur. The relative ease of hydrolysis of the α-1:6-bonds in branched glucans is also investigated.     

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。     

酶法红薯多孔淀粉的制备

多孔淀粉是一种新型酶变性淀粉,采用α-淀粉酶和糖化酶复合酶解法制备红薯多孔淀粉,对其工艺条件进行研究,当α-淀粉酶∶糖化酶为1∶7(体积比),反应温度45℃,反应时间28 h,pH5.6,加酶浓度0.5%,淀粉浆浓度65%时,可得到吸油率较高的多孔淀粉。     

Studies on Sweet Potatoes. Part II: Isolation and Characterization of Starch

By differential sedimentation and centrifugation steps four starch isolates were recovered from sun dried sweet potato flour. The granules in these isolates were of different size, shape and population characteristics, and were anionic in nature. They showed a single stage swelling with 30 to 35% solubility in water and only ∼30% solubility in DMSO even after 72h. Their starch content varied from ∼48 to 88%. The presence of thermostable amylases in sweet potato resulted in considerable decrease in Brabender viscosity values as amylographic studies in the presence of H_gCl₂ showed significant increase in peak (PV) and setback (SBV) viscosities. The starch isolate I had 25% higher PV as compared to the isolate II but retrogradation was much low in this. Susceptibility to glucoamylase digestion showed a decreasing trend from the isolate I to the IV on solid basis, but comparable on starch basis.     

Study on Solid Acid Catalyzed Hydrolysis of Maltose and Related Polysaccharides

Within a study on combined hydrolysis and oxidation of starch toward D -gluconic acid the solid acid catalyzed hydrolysis of maltose as model compound was investigated. Acid zeolites and ion-exchange resins in the H*-form as well as amorphous silica-aluminas were used as the catalysts. The optimal conditions found for maltose were applied in the hydrolysis of amylose and starch. It is shown that the catalysis by zeolites and alumino-silicates involves homogeneous as well as heterogeneous catalysis.     

Rheological Studies on Potato Starch Pastes at Low Concentrations. Part I. Pasting Characteristics

A novel approach is demonstrated to the determination of pasting characteristics. Using a rotatory viscometer measurements are carried out at constant torque and varying angular speed of rotation. Applied device allows application of low torque, and in consequence studies of starch pastes at low concentrations became available. A model is proposed for characteristics of pastes which involves two parameters independent of measurement conditions.     

The Production and Properties of Glucose Syrups I. Production of Glucose Syrups by Enzymatic Hydrolysis of Starch

Certain metal ions are shown to influence the enzymic hydrolysis of maize starch. Amyloglucosidase was not affected by the metal ions but á- and ß-amylase were affected by varying degrees. Calcium ions produced a positive effect with both fungal and bacterial α-amylases but no effect with ß-amylase, whilst zinc, ferric and lead ions produced negative effects or no effect. A simultaneous enzymic hydrolysis (using α- and ß-amylases) and catalytic hydrogenation showed enzyme inhibition by the nickel catalyst. High hydrogen pressure (100 at) had little effect on the enzymes. The hydrolysis and hydrogenation of the starch fraction of milled whole defatted maize was also shown to be feasible.     

The Modification of Starch by High Pressure. Part I: Air- and Oven-dried Potato Starch

Air and oven-dried potato starch was compressed at 0.8–1.2 × 10⁹ Pa for 60 to 600s. Structural studies have shown that observed changes are both pressure and time dependent. The amylopectin shell of starch grains is the component which suffers most essential but rather random damage. The high pressure of 1 × 10⁹ Pa seems to cause some repolymerization of dextrin formed first under compression. The 1.2 × 10⁹ Pa pressure causes further damage of the structure with ordering of the molecules into more crystal-like matter. The compression of the air-dried starch provide the formation of hard solid gels.     

Semi-continuous Hydrolysis of Sweet Potato Raw Starch by Chalara paradoxa Glucoamylase

Effect of preservatives was investigated on semi-continuous digestion of sweet potato raw starch by Chalara paradoxa glucoamylase which digests both raw and gelatinized starch. Potassium metabisulfite strongly inhibited raw starch digesting activity (RDA) although gelatinized starch digesting activity was only slightly inhibited. Potassium sorbate, among the preservatives examined, showed the weakest inhibition (below 10%) on RDA. In the presence of potassium sorbate, semi-continuous digestion of sweet potato raw starch in a 20L scale hollow fiber UF membrane pilot reactor proceeded efficiently at 30% (w/v) initial concentration of raw starch at pH 5.0 and 40°C. Glucose production was 5.7 to 6.0 g/hr/L.     

Effect of Citric Acid on Potato Starch Gelatinization

Coexistent effects of citric acid and acetic acid on gelatinization of potato starch and corn starch are discussed and some difference was found in citric acid but not in acetic acid on potato starch, although any difference was not found between both acids on corn starch. The amylogram of potato starch with EDTA treatment and CaCl₂ treatment supports a presumption that removal of calcium ions bound to phosphate in the starch with citric acid should be responsible to the above acid effect.     

紫薯淀粉的提取及酶解制糖工艺研究

紫薯的精深加工越来越受到人们的关注,而其中紫薯淀粉作为一种重要的食品原料,现已成为开发应用的主要方向之一.通过系列单因素和正交试验,探索紫薯中淀粉的浸提和中温α[-淀粉酶酶解紫薯淀粉的最佳工艺条件,从而确定紫薯淀粉分离提取及酶解糖化的最佳工艺参数.结果表明,在淀粉分离提取阶段最适条件是浸提温度35℃,浸提时间90 min,紫薯浸提液pH 1.5;在淀粉酶解糖化阶段,采用中温α-淀粉酶对紫薯淀粉进行酶解,酶解温度55℃、酶解时间150 min、加酶量500.1 nkat/g,pH 6.     

酸法制备玉米多孔淀粉的工艺优化及其产品特性的研究

对酸法水解玉米淀粉制备多孔淀粉进行了研究,同时采用扫描电子显微镜(SEM)和差式量热扫描仪(DSC)对所制备的多孔淀粉的颗粒结构、热学特性、成孔过程等进行分析,并将其与原玉米淀粉进行比较.其最佳工艺条件为:盐酸为10%、温度为40℃、反应时间为12 h、底物浓度为34%.用最佳工艺制备的玉米多孔淀粉,其比容积、溶解度、膨胀率、透明度和吸附能力较原玉米淀粉都有所提高,特别是吸油率增加显著.扫描电子显微镜(SEM)显示多孔淀粉表面布有凹坑或孔洞,类似蜂窝状结构,其孔径不等,密度不均;与原淀粉比较,差式量热扫描仪(DSC)表明其糊化温度范围变窄,焓变无明显变化,结晶大小均一.     

Studies on the Retrogradation of Starch in Starchy Foods. Part 3. Effect of the Addition of Sucrose Fatty Acid Ester on the Retrogradation of Corn Starch

A model of retrograded starch molecules was proposed in our previous paper. The effect of the addition of n-butyl alcohol or sucrose fatty acid on the retrogradation of starch was studied in this paper. The samples were prepared by repeating freeze-thaw cycles with or without addition of complex forming agents. The samples were treated with 16% sulfuric acid as by Nägeli amylodextrin preparation or a mixture of β-amylase-pullulanase. The residues of the acid or enzyme treatment were chromatographed. From the results of iodine titration, degree of gelatinization, X-ray diffraction, and chain length distribution, it is discussed how the helix forming angents react with fractions of starch and prevent the retrogradation. A schematic model of the retrograded starch with helix forming agents are also proposed.     

响应面法优化甘薯淀粉酶解条件的研究

在加酶量、作用时间、反应温度及pH四个单因素试验的基础上,运用响应面分析法,以甘薯汁中还原糖量为评价指标,对耐高温α-淀粉酶酶解甘薯汁中淀粉的最佳工艺进行了研究,并利用统计学方法建立了耐高温α-淀粉酶酶解甘薯汁中淀粉的二次多项数学模型.结果表明,最佳酶解条件为:加酶量55 U/mL;作用时间80 min;反应温度90℃.在最佳酶解条件下,甘薯汁中还原糖量达3.706 g/100mL,淀粉的酶解率为75.33%.水解后的甘薯汁过滤制得的饮料,无需添加稳定剂,即可达到饮料稳定性的理想效果,在饮料保存期内无沉淀产生.     

磷酸酯化对甘薯淀粉凝沉性质的影响

对甘薯淀粉的磷酸酯化制备条件及产物的凝沉性质进行了系统研究，结果表明，甘薯淀粉磷酸单酯的最适制备工艺为：NaH2PO4：Na2HPO4=3：l；反应温度130℃～140℃：反应时间2～3h，pH5．5～6．0，催化剂用量为淀粉千基重的4％～6％。甘薯淀粉经过磷酸酯化反应后可能在脱水葡萄糖单元上引入了磷酸基团，从而导致了淀粉凝沉性质的变化，使得淀粉糊的凝沉趋势降低，透明度增高，冻融稳定性提高。