Charakteristik der Stärke ausgewählter Kartoffelsorten Teil 1. Änderung des Stärkegehalts und der Stärkekorngröße während der Lagerung

Characteristics of Starch of Selected Potato Varieties. Part 1. Change of Starch Content and Starch Granule Size During Storage . Selected varieties of potatoes of the Czechoslovakian assortment were tested as to their contents of dry matter and starch, as well as to quality of their starch in three-years storage tests. Potatoes were stored in airconditioned boxes at temperatures of + 2 and + 10 °C. Analyses were carried out after harvesting and after storage. It was found that the content of dry matter was higher near the end of storage time. This increase was depending on temperature. Yet, related to dry matter the starch content had not diminished near the end of storage time. During storage of potatoes changes in the share of individual starch granule sizes do also occur. Larger granules were degraded to smaller ones, thereby increasing the latter's share. Higher temperature would also lead to an increase in these changes. The tests were supposed to show, wether during potato storage a change in size of starch granules takes place, and wether storage temperature may influence this change. Work on this problem will be continued.     

Zur Mikroskopie der Stärkekörner von gekeimten Kartoffeln

On the Microscopy of Starch Granules of Germinated Potatoes. Microscopic examinations of normally germinated as well as germinated and dried potato tubers and of the germs as such showed that the generalized assertion of D. Grebel, according to which a “melting” should be characteristical for the fermentative degradation (germination) of starch, cannot be confirmed. Indeed, the described melting phenomena occurred with single starch granules, the majority of the fermentatively deformed starch granules, however, showed the typical changes (channel formation) as they are to be seen with starch granules of cereals. With partially dried potato tubers and their germs the starch granules showed changes like those occurring with curcuma starch. Factors that are responsible for this symptom are being discussed.     

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.     

Isolation and Characterization of Adzuki Bean (Vigna angularis cv Takara) Starch

Starch was isolated from Minnesota-grown adzuki beans (Vigna angularis, cv Takara). The relatively low yield (21.5%) may be characteristic of the isolation method [and may well represent the practical limits for starch recovery for this extraction procedure]. Starch granules were oval to kidney shaped, with mean size 32 μm (range 15-45 μm). SEM micrographs revealed presence of deep surface fissures. Gelatinization temperature range was 64-66-68°C and amylose content was 28.8%. Gardner color values were L = 92.5, a = 0.0, b = 5.6. Starch showed low swelling power and solubility in water. Brabender viscosity patterns showed neither peaks nor breakdown of hot paste. Starch formed stable gels at 5% and higher concentrations; gel strength was similar to that of corn and wheat starch gels, but was definitely stronger than that of potato starch. Retrogradation was greater than in corn or wheat starch gels.     

Physico‐chemical Characterization of Grain Tef [Eragrostis tef (Zucc.) Trotter] Starch

Starch isolated from five grain tef (Eragrostis tef) varieties was characterized and compared with commercial maize starch. Grain tef starch is formed of compound granules, comprising many polygonal shape (2—6 μm in diameter) simple granules. The crude composition is similar to that of normal native cereal starches. The amylose content ranges from 24.9—31.7%. Gelatinisation temperature range was 68.0—74.0—80.0 °C, typical of tropical cereal starches, and resembling the temperature range of rice starch. The mean intrinsic peak viscosity (269 RVU), breakdown viscosity (79 RVU), cold paste viscosity (292 RVU) and setback viscosity (101 RVU) determined were considerably lower than that of maize starch. Tef starch has higher water absorption index (WAI) (mean 108%) and lower water solubility index (WSI) (mean 0.34%) than maize starch.     

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%.     

Studies on the Functional Characteristics and Digestibility of Starches from Phaseolus vulgaris Biotypes

The functional properties of starches from black bean, kidney bean, navy bean, northern bean and pinto bean, all biotypes of Phaseolus vulgaris, were examined. Starch granule sizes ranged from 22 – 39 μm (length) to 19 – 28 μm (width) and shapes varied from elliptical to oval. Amylose content ranged from 30.2 – 37.3%. A highly ordered crystalline structure of granules (Ca) was suggested by restricted swelling power and solubility, resistance to α-amylase attack, high gelatinization temperature and stable amylographic viscosities. Moreover, the existence of a crystalline structure of the highest and lowest order of stability among the Phaseolus starches was indicated for pinto bean and black bean, respectively, which were substantially different than those of kidney, northern and navy bean. The higher stability of pinto bean starch indicated a higher degree of associative bonding forces, namely, hydrogen and covalent, between oxygen and hydrogen atoms of closely packed parallel amylose chains. The wide range in amylographic viscosities was a reflection of crystalline stability, amylose exudation, granule swelling and pH of slurry. Gels exhibited a higher degree of retrogradation at +4 °C than at – 15 °C. Scanning electron microscopy showed that α-amylase-treated corn starch granules were degraded from the inside out by the formation of large circular holes, whereas those of kidney bean were less extensively degraded and showed only scaling and roughening of the surface as evidence of granule deterioration.     

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.     

Stärkekörner im Pflanzenreich Mikroskopische und submikroskopische Morphologie und Evolution

Starch Granules in Vegetation. Microscopic and Submicroscopic Morphology and Evolution According to the reaction in polarized light and by the fractionated swelling in water preparations by heating the starch granules show a clear submicroscopic reaction without evidence about the chemism of the starches. In some plant tribes the starch grains of seeds show different Basic Construction Types (BC-Types) as in the vegetative organs. Some Euphorbiaceae e. g. form rod-shaped starch granules in the nonarticulated lacticifers whilst the adjacent parenchyma cells contain round envelope starch granules. Most of the Pteridophyta, Coniferophyta, Ginkgo, Chlamydospermae and primary Monocotyledons show the so-called Pteridophyta Bas. Constr. Types, resulting from different but unknown behaviour. The multiplicity of starch granules is not only to explain by the polymer carbohydrates, length of chains, ramification and so forth but by the cooperation of “internal” substances of the starch granules from the substratum formed by the amyloplasts. In the Monocotyledons and Dicotyledons exists an increasing tendency to substitute starch granules by other storage substances.     

Isolation and characterization of Mexican chayote tuber (Sechium edule Sw.) starch

Starch was isolated from Mexican chayote tubers (Sechium edule Sw.) and the yield, physicochemical, rheological, and molecular characteristics were investigated. Commercial potato was used for comparison. Starch yield was 49% with a purity of 89.1%. AM content of chayote tuber starch was 26.3%. Birefringence was shown in chayote tuber starch and granules had diverse shapes such as spherical, oval, and polygonal, with size between 10 and 25 µm. B‐type XRD pattern was shown by chayote tuber starch. Chayote tuber starch had higher peak viscosity (PV) than potato starch and the maximum PV for chayote tuber starch was obtained at lower temperature. Flow properties of chayote tuber starch showed higher hysteresis than potato at the same concentration. In chayote tuber and potato starches, G′ > G″ at both temperatures. Chayote tuber starch presented slightly lower gelatinization temperatures, but slightly higher enthalpy of gelatinization than potato starch, and similar retrogradation rate (due to the enthalpy value of the phase transition) were found in both tuber starches. Chayote tuber starch presented higher Mw and Rz values than potato starch. Chayote tuber could be an alternative for starch isolation with specific physicochemical and molecular characteristics.     

Un test d'irradiation de l'amidon. Mode operatoire,application à différents amidons

Proof for Irradiation of Starch. Working Rules and Application to Various Starches . The test which is proposed for the proof of irradiation of starch is based on the determination of the malonaldehyde – which is formed by irradiation – by means of 2-thiobarbituric acid. The study was made on the alteration of the aldehyde content of 3 starches (maize starch, pregelatinized maize starch, potato starch) which had been irradiated with 400 Krad and stored at different temperatures. If water content of the sample, storage temperature and duration of storage are known, the original irradiation dose can be calculated by the obtained graphs. These calculations are of variable precision in the specific cases. It is possible to determine the irradiation of maize starch having been stored for three months at 25 °C, provided that the irradiation dose had been of at least 25 Krad.     

Starch Properties of New Sweet Potato Lines Having Low Pasting Temperature

Some new sweet potato lines were developed from progenies of a new cultivar, Quick Sweet, having a low pasting temperature. Starch granules from these lines demonstrated an abnormal morphology characterized by cracking into fragments. Starch and amylose contents were different among these lines. Pasting temperatures of these lines determined by the Rapid Visco Analyser were 53.8 to 66.6°C, i.e. 10 to 20°C lower than that of the control. Peak viscosities of some lines were similar to that of the control. Starch retrogradation, evaluated by percentage of leaked water and hardness of starch gels after cold storage, revealed that the control starch retrograded during storage for two to six weeks, but the starches of some lines retrograded much more slowly than the control starch and exhibited excellent cold storage stability. The pasting temperature had significant positive correlations with the percentage of leaked water and the hardness. These results indicate that Quick Sweet is a useful breeding material for improving pasting and retrogradation properties in sweet potato starch.     

Untersuchungen über den Einfluß von Umwelt,Sorte und Düngung auf die Korngröße der Kartoffelstärke

Studies on the Influence of Environment, Variety and Fertilization on the Granule Size of Potato Starch. The influence of various factors of cultivation technology on the composition of granule size of potato starch was studied. It was found that the influence of year and location are of vital significance. Under same conditions variety and fertilization influenced the size of the starch granule but to a lesser degree. In agreement with literature it was found that large potato tubers show a higher content of large starch granules than small granules. Nitrogen became only effective above 160 kg per hectare in increasing the content of large starch granules.     

Charakteristik der Stärke ausgewählter Kartoffelsorten Teil 2. Gehalt an Phosphor,Kalium und Calcium in der Stärke

Characteristics of Starch of Selected Potato Varieties. Part 2. Phosphorus, Potassium and Calcium Content in the Starch . It was found that during storage of potatoes not only changes in starch content and size of the starch granules do occur, but also changes in phosphorus, potassium and calcium content in the starch. The potassium content decreases during storage as a function of temperature. The phosphorus content decreases at +2°C and increases at +10°C. The calcium content increases in the final stage of storage. The phosphorus content in the starch decreases during storage. These results are of special significance with a view to preservation of starch quality.     

Some Properties of Normal- and Waxy-Type Starches of Amaranthus hypochondriacus L

Starch granules were prepared from seeds of two types of Amaranthus hypochondriacus L., which are native to Nepal. The perisperm of one type of seeds stained reddish-brown with iodine solution and that of the other blue. Starch granules had round shape of about 1 μm diameter. X-ray diffraction diagrams were very similar each other and identical with the corresponding ones of rice and maize starches (A-type). Amylose contents and distribution of average chain-lengths of amylopectin were determined by gel filtration for isoamylase-debranched starches. Amylose content was about 14% and 0%, resp. Both types of Amaranthus starches had typical amylopectin nearly identical with those of rice and maize starches. Starch-granule digestibility by amylases and pasting characteristics of the Amaranthus starches were similar to those of fine starch granules.     

Studies on Starch from an Indian Crocus

The molecular properties and granular appearance of a starch from an Indian crocus (Crocus sativus) have been examined by methods involving iodine-staining, enzymic degradation, gel chromatography and scanning electron microscopy. The granules were relatively small (3 – 15 μm), and had a rough surface and flattened facets indicative of close packing. The amylose content of 27.4% was rather higher than that of many cereal and potato starches but came within the higher end of the range of “normal” values.     

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.     

Stärkegewinnung aus konserviertem Kartoffelreibsel

Starch Production from Preserved Potato Gratings. During industrial starch production potato gratings are produced which can be preserved by the addition of a 1.2% sodium hydrogensulfite solution. Preserved this way the durability of the gratings is defected neither by extreme differences in temperature nor by storage of 6 months and even longer. After storage the gratings can be returned into the industrial process to obtain the starch by washing out. The quality of this starch differs from the quality of potato starch washed out from non-preserved gratings: The pH-value is somewhat lower and the hot paste viscosity is slightly reduced. Contrary to this the typical curve of potato starch in the Brabender-Viscograph remains the same.     

Extraction,Physicochemical and Compaction Properties of Tacca Starch — a Potential Pharmaceutical Excipient

Some physicochemical properties of tacca starch (Tacca leontopetaloides, Taccaceae) have been examined and the results compared to those of maize and potato starches. Tacca starch was found to have a higher amylose content than maize starch but a lower content than potato starch. The starch granules were small (average particle size 3.5 μm) relative to maize and potato starches and were predominantly polyhedral with edges. The gelatinisation characteristics except from the temperature were similar to those of maize starch but much higher than those of potato starch. Tacca starch had relatively higher swelling power and solubility than the other starches. Its features in the formation of compacts (tablets) were comparable to those of maize starch with tacca starch being more resistant to deformation.     

Analysis of Starch in Food Systems by High‐Performance Size Exclusion Chromatography

Starch has unique physicochemical characteristics among food carbohydrates. Starch contributes to the physicochemical attributes of food products made from roots, legumes, cereals, and fruits. It occurs naturally as distinct particles, called granules. Most starch granules are a mixture of 2 sugar polymers: a highly branched polysaccharide named amylopectin and a basically linear polysaccharide named amylose. The starch contained in food products undergoes changes during processing, which causes changes in the starch molecular weight and amylose to amylopectin ratio. The objective of this study was to develop a new, simple, 1‐step, and accurate method for simultaneous determination of amylose and amylopectin ratio as well as weight‐averaged molecular weights of starch in food products. Starch from bread flour, canned peas, corn flake cereal, snack crackers, canned kidney beans, pasta, potato chips, and white bread was extracted by dissolving in KOH, urea, and precipitation with ethanol. Starch samples were solubilized and analyzed on a high‐performance size exclusion chromatography (HPSEC) system. To verify the identity of the peaks, fractions were collected and soluble starch and beta‐glucan assays were performed additional to gas chromatography analysis. We found that all the fractions contain only glucose and soluble starch assay is correlated to the HPSEC fractionation. This new method can be used to determine amylose amylopectin ratio and weight‐averaged molecular weight of starch from various food products using as low as 25 mg dry samples.