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.     

Möglichkeiten und Vorteile der Vakuumreibe in der Kartoffelstärkeindustrie

Possibilities and Advantages of Vacuum Rasp in Potato Starch Industry When rasping potatoes the impact of air causes oxidation and as a consequence undesired discolorization of potato protein and pulp. Therefore, sulphur dioxide or sulphites are usually added during processing. An alternative solution seems to be rasping of potatoes in an oxygen-free system. The new procedure consists basically of an adequate infeed, a circulation system and a gas-tight rasp with discharge. The potatoes are fed by a water stream through an U-formed tube and via dewatering grid into the vacuum chamber of the rasp. Due to the difference in atmospheric pressure the mixture flows spontaniously into the rasp casing, so a pump is not required. The vacuum has a favorable influence on the noise-level of the rasp and on the protein quality.     

DSC-Untersuchungen an Stärke Teil I. Möglichkeiten thermoanalytischer Methoden zur Stärkecharakterisierung

DSC Investigations of Starches. Part I. Feasibility of Thermoanalytical Methods to Characterize Starches. In this paper results on the application of Differential Scanning Calorimetry upon the gelatinization and reorganization of starch polymers (retrogradation) are discussed. Considerable emphasis was layed on optimization of the analytical method. A high caloric sensitivity related to the sample volume was accomplished based on a specific detector system of the used calorimeter. Due to these optimized conditions – besides known endothermal enthalpy changes during gelatinization – for some starches additional peaks could be detected that are attributed to the desintegration of the amylose-lipid-complex. Using mixtures of amylose and amylopectin, discrete peaks from their retrogradation products are observed under certain circumstances. These differ clearly by transition temperature. Finally, gelatinization effects are discussed using limited water supply. Recently published results could be confirmed. Differential Scanning Calorimetry has been fully developed to an useful analytical method to answer questions within starch chemistry.     

Verarbeitung von Kartoffelstärke auf Kunststoff-Verarbeitungsmaschinen

Processing of Potato Starch on Plastics Processing Machines. Starch as an organic material with macromolecular structure has many properties comparable to usual plastic materials. Therefore, it is possible to manufacture starch products with polymer processing machines by the same methods as synthetic polymers. In addition of special plasticizer native potato starch has been processed to granules and films with different extruders. The granules were taken as feed material for experiments of the production of samples with an injection moulding machine. The mechanical properties of the produced specimens proved to be on a satisfactory level. By the suitability of the widely distributed screw machines for starch processing it is possible to substitute synthetic polymers by starch for special applications without high inital costs. Detailed knowledge about the suitable processing methods is an important condition for that.     

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.     

Möglichkeiten einer Standardisierung von Viskositätsmessungen zur vergleichenden Beurteilung der rheologischen Eigenschaften und des rheologischen Verhaltens der Stärke

Possible Standardization of Viscosity Measuring Procedures for a Comparative Valuation of the Rheological Properties and Behaviour of Starches . As generally known, in both starch research and starch industries numerous different apparatus for viscosity measurement are used which produce rheological data by the scale and measuring systems of the instruments applied. However, the test-data obtained can not be compared on principle because of those different scale and measuring systems fixed to each instrument. Furthermore, no suitable procedure as standardized method is availably up to now. The standardization of suitable methods on the other side presupposes that the apparatus for viscosity measurement themselves produce reproducible results when uniform working directions are used. For that reason the viscosities of various potato, maize, rice and wheat starches were determined under different test conditions by utilizing the Brabender viscograph, Rotovisco instrument and Hoeppler falling-ball viscosimeter in order to establish optimum conditions for the reproducibility of results obtained. Thereby those three apparatus for viscosity measurement were selected in particular under technological aspects of application. As result of the comprehensive investigations it seems to be quite possible to criticize and review comparatively the rheological properties and the rheological behaviour of starches with regard to their importance in the special field of technical application, if the existance of suitable and also standardized methods guarantees a sufficient reproducibility of the test-data.     

Chemische und verfahrenstechnische Gesichtspunkte zur Herstellung von kationischer Kartoffelstärke durch Kochextrusion

Chemical und Processing Aspects of the Production of Cationic Starch Using Extrusion Cooking. Cationic potato starches were produced by carrying out the chemical reaction under varying extrusion cooking conditions in order to investigate the influence of the extrusion parameters on the reaction efficiency (R.E.) and the degree of substitution (D.S.) dependent on this. The extrudates were used to develop a suitable analytical method for an accurate determination of the D.S. To achieve the necessary analytical accuracy all nitrogen containing substances not chemically bound to the molecules of the starch must quantitatively be extracted from the cationic starch prior to the determination of its nitrogen content. It could be shown by extraction experiments that the extractability of such substances from ground cationic potato starch extrudates is dependent on the penetration of the solvent through the extrudate particles and the diffusion of the soluble substances in the particles into the solvent. Optimal results for the R.E. were achieved by suspending one part ground cationic potato starch extrudate in ten parts solvent consisting of 80% Ethanol and 20% water (w/w). The suspension had to be kept in a sealed glass vessel for 40min at a temperature of 80°C. Within the experimental range of the extrusion experiments the reaction conditions for the cationization could be kept constant. Besides the formulation of the reactive components the D.S. was influenced by the variation of the extrusion parameters. A. R. E. of 80% was achieved over the investigated range for the D.S. of 0.03 to 0.10.     

Stärke als Chemierohstoff — Möglichkeiten und Grenzen

Starch as Raw Material for the Chemical Industry – Chances and Limits. As further, renewable raw material sources for the chemical industry are being opened up, starch may assume an important role. As a natural polymer capable of undergoing conversion and modification it could be adapted in a very flexible way to the requirements imposed on a product that is to be used as a raw material for biotechnical or chemical processes. There are different ways of including starch products in the production and/or processing of synthetic polymers which are explained here by reference to polyolefins, polyurethane foams and various condensation resins. By selective, preferably enzymatic conversion of the starch and by subsequent hydrogenation of the resulting mixtures of mono- di- or oligosaccharides it is possible to obtain a wide range of polyols. Anhydro compounds formed, for example from sorbitol, yield bicyclic polyols with the functionality 2 for which manifold outlets are certain to be found not only in polymer chemistry. The possible uses of starch as a chemical raw material which are described here, as well as other conceivable uses could be a serious contribution to a solution of raw material and energy problems.     

Vergleich einiger charakteristischer physikalisch-chemischer Daten modifizierter Weizen- und Kartoffelstärke

Comparison of the Characteristic Physico-Chemical Data of Modified Wheat and Potato Starches. A comparison of some physico-chemical properties of wheat and potato starch has been given with regard to their behaviour before and after treatment by mild modification procedures. In this way a survey of the characteristic data of both starch sorts was obtained, i. g. the swelling and solubility capacities, the viscosity and limiting viscosity, extraction of the starch films, the X-ray diffraction patterns a. o. which were elucidated and discussed.     

Anmerkungen zur Qualität der Erbsenstärke

Notes on the Quality of Pea Starch. The opening of additional markets for the starch industry needs partly starch qualities differing from those of common starches. Here, pea starch can be used successfully as our investigations show. Nevertheless, the extreme difference between the starches of the two botanical subspecies sativum (smooth) and medullare (wrinkled) of pisum sativum L. (pea) is of principle significance. With regard to our investigations it is a character for smooth peas having a starch content of about 50% i. dm, whereas wrinkled peas only reach values of about 30% i. dm. Regarding the size of the starch granules the smooth pea starches show a content of more than 50% small granules with diameters lower than 20 μm compared to wrinkled pea starches with even 100% small granules. The amylose contents of smooth pea starches exceed with 40% the values of the traditional starches but the contents of wrinkled pea starches are even about 70%.     

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.     

Mikroskopische Untersuchung hypochloritoxydierter Kartoffelstärke

Microscopic Examination of Hypochlorite-Oxidized Potato Starch . By means of light and scanning-electron-microscopy the primary oxidation effect of hypochlorite is proved to affect the interior of the potato starch granule. Electron-microscopic photos show hollows in the kernel which are brought about by oxidation.     

Die Selbsthydrolyse der Kartoffelstärke. 2. Mitt. Selbsthydrolyse von Kartoffelstärkekörnern in wäßriger Suspension

Self Hydrolysis of Starch. Part 2. Self Hydrolysis of Potato Starch Granules in Aqueous Suspension. Tests with potato starch have shown that self hydrolysis at temperatures below the starting point of irreversible swelling leads to the formation of low molecular, soluble degradation products containing bound phosphoric acid. The rest of starch granules show increased reducing power as well as hydrothermically caused ageing. Approaching the end of self hydrolysis the substrate acts like thin boiling starch. During self hydrolysis phosphoric acid bound like ester is set free. Speed of self hydrolysis increases with increasing phosphorus content, whereas formation of free phosphate is independent of this factor.     

Gewinnung von Kartoffelstärke unter Verwendung des Abwassers als Düngemittel

Extraction of Potato Starch Utilizing Wastewater as Fertilizer . In Sweden the method of washing out the starch from the potato rasp with the undiluted fruit juice of the potato has been developed to higher yields of undiluted fruit juice. By concentration on a specially constructed vacuum filter followed by adding of water to the filter cake, the remaining fruit juice can be forced out, so that only about 0.03% N is left in the starch after filtration. This means that from the fruit juice of the potato about 20% remain in the pulp and about 78% in the fruit juice. The fruit juice is spread by vehicles in portions of 2.5–3 mm, what corresponds to about 100 kg N and 150 kg potassium/ha. The required area is about 130 ha/1000t of commercial starch. It was possible to reduce the amount of wash water to 50–100l/t of potatoes by recycling.