Einfluß der Stärke auf die Textureigenschaften von Kartoffelknollen

Interaction of Starch and Textural Properties of Potato Tubers. By a two years glas-green-house test the influence of starch content on texture of raw and boiled potatoes was studied. Results show that only at certain conditions the starch content can affect a tendency of influencing the texture. Physical properties of starch play as well an important role referring to the texture of tubers. With reference to the influence of starch on texture of potato tubers other factors seem to play a role which still must be investigated.     

Untersuchungen über die Retroaradation der Stärke in konzentrierten Weizenstärkegelen. Einfluß von Stärkeabbauprodukten auf die Retrogradation der Stärke

Investigations on the Retrogradation in Concentrated Wheat Starch Gels. Part 2. Effect of Starch Degradation Products on the Starch Retrogradation . In the present work the influence of added starch degradation products on the rigidity and retrogradation of 50% wheat starch gels was investigated. The gels prepared with the addition of maltodextrin were extracted with 40% ethanol, the extracts were analysed for glucose oligomers. The effect of the added starch degradation products was dependent on the degree of degradation. Weakly degraded, acid modified starches take part in the retrogradation process as do white and yellow dextrins as well as maltodextrins with dextrose equivalents (DE) <30. Maltodextrins and glucose sirups with a DE ≧ 30 act as plasticizers: in concentrations of 5-30% (based on starch d. s.) they reduce gel strength without affecting the retrogradation velocity. The plasticizing effects are particularly evident with maltose and maltotriose as well as maltotetraose and pentaose. Even so the extractibility of oligomers with a degree of polymerisation (DP) ≥ 6 was reduced, the hexamer and octamer might still have a plasticizer effect. With glucose, concentrations ≥ 26% were needed to observe plasticizing. The relation of these findings to bread staling is discussed.     

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.     

Kochextrusion von Stärke mit Hydrokolloiden

Cooking Extrusion of Starch with Hydrocolloids. Cooking extrusion of corn starch with the hydrocolloids xanthan, gummi arabicum, galactomannan and carrageenan yields in the case of corn starch with 5–30% xanthan products of excellent properties. Until now a synergistic effect between xanthan and galactomannan in water solution has been described as an interaction of β-1,4-linked chains of the both polysaccharides. Now it has been shown that cooperative linkage of β-1,4-D-glucan-chains of xanthan with α-1,4-D-glucan-chains of starch take also place under the conditions of cooking extrusion process. Pressure and torque measurements, and calculation of specific energy dissipation point to an evident interaction which is dependant on the xanthan concentration. High water binding capacities and interesting behaviour in viscosity mark those products as a suitable new class of hydrocolloids.     

Auswirkungen einer Feuchtkonservierung von Mais auf die Stärkequalität

Effect of Wet-Conservation Technique of Corn on Starch Quality. A corn starch production by German corn is practicable with reservation. Since the moisture content of the cernels varies between 30 and 40% instead of drying two wet conservation techniques were tested. With the experiments of using sodium hydrogensulfite no remarkable differences of quality criteria in comparison with non stored reference starches were observed along with the storage about 24 weeks. The ensiling of corn-cob-mix by a lactic acid fermentation resulted in starches of high quality, too. Consequently these two kinds of wet conservation techniques of storage are suitable in the same manner for starch production.     

Untersuchungen über den Einfluß der Verarbeitungsbedingungen auf die Qualität von tiefgefrorenen Pommes frites

Examination on the Influence of Processing Conditions on the Quality of Deep-Freeze French Fried Potatoes. In order to test qualification of German potato varieties for manufacturing of deep-freeze French fried potatoes and the influence of processing conditions on the quality of this product, potatoes of 1971 to 1973 harvests from the regions of Rain and Soltau were examined in a 3-year large scale test; in particular the varieties of Bintje, Datura and Hansa were chosen. The stored potatoes – after washing and peeling – were cut, blanched (whitened), pre-fried and finally frozen. After one year of deep-freeze storing the products were taken out, fried again and subjected to quality analysis. Colour and taste tests as well as apparent consistency have led to the result that the varieties of Bintje and Datura from both regions of cultivation are suitable for the production of French fried potatoes, whereas the variety of Hansa cannot be recommended for the production of deep-freeze French fried potatoes. Various technological process modifications have not led to any significant improvement of the quality of French fried potatoes compared to the conventional processing method.     

Einfluß der Düngung auf die Viskosität von Kartoffelstärke

Effect of Fertilization on the Viscosity of Potato Starch. In three years of field tests with graduated doses of calcium and magnesium for the potato cultivar Radka it was shown that starch content during particular growing phases is influenced by calcium and magnesium doses in conjunction with N-, P-, K-doses. Viscosity is also depending on addition of calcium and/or magnesium. Addition of these both fertilizers, however, effects also in connection with the N-, P-, K- doses. Highest starch content was found under the condition of variant N₁P₁K₁ · Mg₁. On the other hand highest viscosity was observed with variant N₃P₂K₂ · Ca₁.     

Kernresonanzuntersuchungen zum Einfluß der technischen Aufarbeitung auf die Wasserbindungsfähigkeit von Kartoffelstärke

Nuclear Resonance Investigations Regarding the Influence of the Preparation on the Water Binding Capacity of Potato Starch . In a preceding paper we stated that an increased content of more tightly bound water has been observed in a sample of industrial potato starch in comparison with a sample of starch which has been isolated under carefully controlled conditions. Now it can be shown that the conditions of drying and also the size of the starch granules have no influence on the above mentioned difference, in spite of the fact that the portion of more tightly bound water distinctly depends on the granule size. The differences in the behaviour of the bound water can be explained by the ion content of the water used during the isolation of the starch. The mechanism of this effect, however, is not yet clear.     

Zur Bestimmung der Scherbeständigkeit von Stärkekleistern

On Determination of Shearing Stability of Starch Pastes. Test conditions for the shearing stability test of starch pastes are not sufficiently outlined in existing publications. In the present paper, first of all a determination of optimum parameters (type of paste production, type of stirrer, stirring time, stirrer revolutions, viscosity measurement etc.) for a shearing stability test was attempted. It became apparent that shearing treatment of 5 min by means of a blade stirrer at a number of stirrer revolutions of 1800 r.p.m. with a 5% paste concentration is sufficient to determine shearing stability of a starch paste. For viscosity measurement which as well as pasting and shearing stress is carried out a 95 °C, a Brookfield viscosimeter is used. Provided measuring conditions (type of spindle, spindle revolutions) are kept constant before and after shearing stress, shearing stability can be expressed as remaining viscosity as a percentage of the initial viscosity. Furthermore, reproducibility of paste production as well as that of the whole shearing stability test were determined. Finally, a test was carried out as to wether there is a connection between shearing and heat stability of paste. Values obtained from 11 commercial products made such a connection between the two criteria apparent.