Chromatographische Untersuchungen zur Polydispersität von Hydroxyethylstärke

Chromatographic Studies on the Polydispersity of Hydroxyethyl Starch. A representative sample of clinically used hydroxyethyl starch was separated by semipreparative HPSEC into narrow fractions in the range of approx. 3.000 to 800.000 D. The original sample and selected fractions were characterised by gaschromatographic methylation analysis according to their substitution degrees MS and DS, which were differentiated by the substitution positions at C2, C3 and C6 of the anhydroglucoses and their kind of glycosidic bonding α-1, α-1,4 or α-1,4,6, respectively. Furthermore, polydispersity in relations to the degree of branching was determined. Mark-Houwink and molecular weight distribution parameters determined by multi-detection HPSEC are reported. The presented data demonstrate a extensive homogeneity of the original sample. The clinical relevance is discussed.     

Systematische GC/MS-Analyse von 1,2-O-Ethylenglucose-Derivaten in Hydrolysaten von Hydroxyethylstärke

Systematic GC/MS Analysis of 1,2-O-Ethylenglucose Derivatives in Hydrolysates of Hydroxyethyl Starch . In hydrolysates of hydroxyethyl starch sixteen 1.2-O-ethylen-D-glucose derivatives were identified by GC/MS after persilylation. Beside the common MS fragments of silylated compounds four significant fragments of the bicyclic intramolecular glucosidation products of monocyclic (2-O-hydroxyethyl)glucose derivatives were found: m/z 86, 127, 229 and 277. These ions allow an identification of trimethylsilylated 1,2-O-ethylenglucose derivatives in a complex matrix and in addition the differentiation of isomers and anomeres. The typical fragmentation pattern of TMS-1.2-O-ethylenglucose derivatives is described and is verified by the study of the corresponding acetyl derivatives.     

Einfluß von Sorte und Standort auf die Viskositätseigenschaften von Kartoffelstärke

Influence of Sort and Locality on Viscosity Properties of Potato Starch. Regarding its rheological properties potato starch holds a special position compared with all other starches, which is mainly due to the phosphoric acid, resp. phosphate groups bound ester-like to the amylopectin. The present work was carried out in order to find out, whether rheological properties of potato starch are also affected by outer influences such as year of cultivation, locality and sort. A marked influence of year of cultivation and locality as well as a less marked influence of the sort on phosphate and ash content of the starches became apparent. Locality exerts the strongest influence on viscosity. An influence of the sort can be stated, but it is mostly obliterated by superimposition.     

Elektronenmikroskopischer Beitrag zur Kenntnis der Feinstruktur der Weizenstärke

Electron Microscope Contribution to the Study of Fine Structure of Wheat Starch . Electron microscope investigations of the fine structure of wheat starch granules were carried out using a combined fixation and staining technique. It was found that amylose is particularly concentrated in the nucleus. Uranophilic layers seem to indicate the presence of protein in the outermost surface regions of the starch granules. The radial orientation of the helicoidal unit chains of amylo-pectin could be confirmed. In both tangential and radial sectioning directions characteristic features of hexagonal structure are shown.     

Über den Feinbau von Kartoffel- und Weizenstärke

The submicroscopic radial structure of the starch granule can be explained by folded-chain crystals better than by microfibrils. Such microfibrils described especially by Sterling and also observed by myself may be artefacts which are caused by steps of carbon coated fracture planes of starch granules. The partly submicroscopic tangential shell structure of the starch granule is probably caused by a periodical change of higher and lower molecular fractions both of amylose and amylopectin. This conclusion follows from staining and fluorochroming as well as from phosphoric tungstic acid contrasting experiments in light and electron microscopy. The more crystalline layers consist exceedingly of high molecular fractions. The less tight and more amorphous regions of layers which are easier oxydated (e. g. by periodic acid) and hydrolysed (by a-amylase) are composed of lower molecular fractions rich in phosphorus and nitrogen containing compounds (especially in wheat starch) and therefore are more hydrophilic and abounding in water.     

Radiolyse von Stärke Beitrag zur quantitativen Bestimmung einiger Radiolyseprodukte in Kartoffelstärke und Weizenmehl

Radiolysis of Starch. A Contribution to Quantitative Determination of Several Radiolysis Products in Potato Starch and Wheat Flour . The amounts of formed desoxy-compounds, which produce malonic dialdehyde during HI O₄-oxydation, as well as that of ω-hydroxymaltol have been determined in irradiated potato starch and irradiated wheat flour in dependence on irradiation doses. With pure potato starch, G-values*) of 0.03–0.04 for water soluble desoxy-compounds and such ones of 0.02 for insoluble desoxy-compounds were obtained. G-values of desoxy-compounds in an ethyl acetate-acetone-water extract (4: 5: 1 v/v) of irradiated potato starch and irradiated wheat flour showed a ratio of about 3: 1. When aqueous potato starch sols are irradiated desoxygroups in the high-molecular starch molecule will also be found (in N₂O atmosphere: G-values around 0.3). With ω-hydroxymaltol it became apparent that the main part of this compound is formed after irradiation during storage. With pure potato starch G-values around 0.015–0.02 were determined after 10 days of storage. When this material is heated after irradiation an increase of the hydroxymaltol content (G-values: 0.025) is to be found. In the non-irradiated materials traces of desoxy-compounds as well as ω-hydroxymaltol were found.     

Die Nutzung der Nah-Infrarot-Spektroskopie (NIR) zur Prozeßkontrolle bei der Synthese von Hydroxyethylstärke (HES)

The reaction of starch and ethylene-oxide giving hydroxy-ethyl starch (HES) can be controlled by near infra-red spectroscopy (NIR) The controlled parameter is the molar substitution (MS), which is measured by means of a probe directly from the neutralized and filtered reaction solution. According to the type of HES (200/0.5, 130/0.4 or 50/0.2) the measured MS depends on the concentration of HES in the solution. To prevent distorted results the content of HES 130/0.4 and HES 50/0.2 must be adjusted to 25% (w/v) for this individual calibration. Only in the case of HES 200/0.5 the concentration can vary between 19 and 29% for measuring the MS. Sodium chloride as a byproduct of the process does not effect the measurement up to 10% NaCl in the sample. The temperature of the solution does not influence the result significantly (in the range of 20 to 34°C). The reproducibility of the MS determination is good. The day-to-day standard deviation of 25 repetitions is +/– 0.005 for a sample with MS = 0.405. The relative standard deviation is 1,1%. Nevertheless the biggest problem for the determination of MS by NIR is ethylene glycol (EG), the most important by-product of the reaction. If the concentration of EG differs significantly from that in the calibration samples, the calibration of the method must be revised.     

Darstellung und gezielte Polykondensation von Anhydroalditol-Bausteinen aus Stärke

Synthesis and Directed Polycondensation of Starch-Derived Anhydroalditol Building Units . Using regioselectively acylated derivatives of 1,4: 3, 6-dianhydro-D-sorbitol (DAS) a series of different oligomeric terephthalic acid esters were synthesized and subsequently analyzed. By melting condensation of terephthalic acid dichloride and various dianhydrohexitol derivatives the preparation of certain polyterephthalates was achieved. Related 2,5-diamino compounds were obtained by a facile synthetic procedure from 1,4: 3,6-dianhydrohexitols, and their polycondensation with the bisdichloroformate of DAS led to novel polyurethanes. The polycondensates were characterized by their polymer parameters.     

Stufenweise Elutionsanalyse elektrodialysierter Fraktionen von Wachsmais- und Amylosestärke

Stepwise Elution Analysis of Electrodialysed Fractions of Waxy Corn- and Amylose Starch. Changes in the sol and gel fractions of waxy corn- and amylose starch during thermic dispersing were observed by stepwise elution analysis. The sol- and gel fractions were separated from pastes and dispersions, after being treated in an autoclave at 120°C, by electrodialysis. It was found that during the thermic dispersing the sol- and gel fractions of waxy corn paste decompose more intensively than the analogous fractions of amylose starch. Addition of alkali to the sol fraction of waxy corn- and amylose starch has no influence on the chromatograms. Especially in the gel fraction of amylose starch paste and partially also in the gel fraction of waxy corn starch paste fragments can be observed which after addition of alkali disaggregate. In the sol fraction of the paste of waxy corn starch only 9% of starch could be detected, in the sol fraction, isolated after 3 h of dispersing in an autoclave, however, 45% approx. were determined. In the analogous fractions of amylose starch no increase of the starch contents was observed.     

Die Verteilung von Stärke und Amyloseanteilen in der Kartoffelknolle

Distribution of Starch and Amylose Components in the Potato Tuber. Distribution of dry matter and starch in potato tubers has been studied. Moreover, distribution of amylose components of the starch and qualitative properties of the isolated starch as well as the interrelation between the received data have been examined. From the results it is seen that with most varieties a tendency towards an increase of the dry matter content at the navel end is perceptible. This tendency is more distinct with big tubers. On an average, the starch content was higher at the navel end than at the crown end of the tuber with almost all samples. Starch from big tubers shows a higher viscosity than that obtained from small tubers. Viscosity of the starch from the navel end of small tubers is lower than that from the crown end; with big tubers this is the other way round. Amylose content of starch from small tubers is lower than that from big tubers. Starch, which had been isolated from the crown end of small tubers contained mainly a lower amylose content than the starch isolated from the navel end. Again the situation was the other way round with big tubers. Quality of starch is furthermore also determined by the size of the starch granules. With big tubers a higher amount of bigger granules is to be found. This must be contributed to the fact that in big tubers a higher stage of maturity is reached. Another factor that has been very rarely examined so far is the steeping temperature of starch granules. Apparently the vegetation year has its influence on this factor, too. Differences between the two parts of the tuber were insignificant with small tubers. With big tubers the average steeping temperature of granules was higher in the navel end than in the crown end. The whole complex has been examined from the point of view that the origin of the starch does not have a great significance, although here an interrelation might have been expected. The following relations have been stated by means of the correlation coefficient: amylose content, viscosity, granules (21–40 μm), granules (41–70 μm), average granule size. From the results it is clear that the correlation coefficient between starch content and the amylose content is negative. The correlation between granules of the second (21–40 μm) and the third (41–70 μm) category also proved to be negative. From the basis of the correlation coefficients a regression equation for the statistically secured results may be calculated.     

Papierchromatographischer Trennungen zum Nachweis von nativer und modifizierter Weizenstärke

Paperchromatographic Separation as Identification Method of Native and Modified Wheat Starch . The previous experiences with paperchromatographic separation as identification method of native and modified starch samples has been useful in the study of wheat starch. This technique has been applied to the separation and identification of amylose and amylopectine of native and modified wheat starches (treated by phosphate, mineral acids and different temperatures). The results thus obtained were compared with the physico-chemical characteristics of the same material. The modification procedure and the temperature influence are precisely outlined. The evaluation of the final data permits one to judge the applied technique favourably, the method can be considered as useful and complementary in the analysis of starch material.     

Einfluß von Spurennährstoffen auf den Stärkegehalt von Kartoffeln und die Qualität von Kartoffelstärke

The influence of Trace Element Fertilizers on Starch Content of Potatoes and Quality of Potato Starch. The influence of added trace element fertilizers on starch content and yield of potatos was examined, and among other things the size of starch granules was determined. The trace element fertilizers influence the increase in tuber weight and starch yield and they do not impair starch quality which is expressed in granule size. Boron, manganese and zinc have an optimum effect at certain amounts, whereas copper does not show favourable effects on sand cultures.     

Stufenweise Elutionsanalyse von Carboxymethylstärke

Gradual Elution Analysis of Carboxymethyl Starch . Paperchromatographic elution separation with perchloric acid solutions of different molarities were carried out with synthesized carboxymethylated starches (CMS) of the following degrees of substitution (DS): 0,30, 0,58, 1,09 and 2,17. On the basis of occurring coloured sections in comparison with those of native starch it could be stated that the native starch is subjected during the CMS-synthesis to a partial degradation. A comparison of the chromatograms of the starch ethers indicates for higher DS a change into violet colours, a fading of these colour intensities and an arising of new coloured sections which were separated by lower concentrations of perchloric acid. Already at a degree of substitution of 2,17 any coloured sections are lacking. Induced carboxymethyl-groups in the course of the synthesis prevent the formation of the iodine complex of amylose and the amylopectin-iodine reaction. At defined conditions of the CMS-synthesis the paperchromatographic elution separation makes it possible to evaluate the approximate degree of substitution of starch on the basis of the occurring coloured sections and colour shades.     

Stufenweise Elutionsanalyse elektrodialysierter Fraktionen von Mais-Sorghum-, Kartoffel- und Weizenstärke

Stepwise Elution Analysis of Electrodialyzed Fractions of Maize-, Sorghum-, Potato- and Wheat Starch. Changes in the sol and gel fractions of maize-, sorghum-, potato- and wheat starch during thermic dispersing were followed by stepwise elution analysis. The sol and gel fractions were separated from pastes and dispersions by electrodialysis. Qualitative evaluation of the changes in the chromatograms after thermic dispersing of the pastes is in correlation with the decreasing value of molecule masses of the sol and gel fractions. Additional dispersing of the gel fractions with alkali leads to disaggregation of eventually present traces of starch fragments on the starting spot of the samples, whereas the chromatograms of the sol fractions do not change after addition of alkali. Correlation between the percentage of the gel fraction in the starch – the amylopectin constituent – and the molecule masses during the thermic dispersing was pointed out. With continued dispersing at 120°C the gel content in the starch becomes smaller, while the value of the molecule mass of amylopectin in the gel fraction decreases. During 3 h of dispersing the starch contents in the gel fractions of maize- and sorghum starch pastes showed a decrease of about 65%, the gel fractions of potato starch paste a decrease of 31% and the gel fractions of wheat starch paste a decrease of 25%.     

Einfluß von Calcium auf Gehalt und Ertrag an Trockensubstanz und Stärke bei Kartoffeln

Effect of Calcium on Content and Yield of Dry Substance and Starch in Potatoes. During three years of glasshouse experiments with the late potato variety Kamyk the doses and different applications of Calcium have been tested. It was stated that tuber weight is high significantly influenced by the calcium dosage. Calcium decreased the dry substance content while the starch content was increased. The yield of dry substance and starch was also influenced. Besides of the tuber yield the content of dry substance and starch contributes to this influence. Depending on the way of application calcium fertilizing increased also the amount of reducing sugars.     

Bestimmung der funktionellen Gruppe und des durchschnittlichen Substitutionsgrades von Carboxymethylstärke

Determination of the Functional Group and the Average Degree of Substitution of Carboxymethyl Starch. To characterize chemically modified starch derivatives, it is necessary to know their proportion of functional groups. In the case of carboxymethyl starch, it is the molar ratio of the  CH₂COONa group to the glucose units of the starch molecule which gives the average degree of substitution. With the present method of analysis, developed for production control, the  CH₂COONa group of the carboxymethyl starch is determined by precipitation of its copper salt and back titration of the excess copper in the filtrate with ethylenediamine tetraacetate using Murexide as the indicator.