No abstract

Potato, wheat and corn starches were segregated into large and small granule fractions. The specific surface area, volume, and average diameter of pores, as well as the pasting characteristics of starch dispersions in water were determined. In all the starches investigated the small granule fractions were characterized by the largest specific surface area, pore volume and pore diameter in comparison to fractions of large granules and the initial starches. The small granule fraction of potato starch gave better pasting characteristics (apart from maximum viscosity) than fractions of large granules and the initial potato starch. On the other hand, the large granule fractions of corn and wheat gave the highest maximum viscosity

Three Polish varieties of oat starch were subjected to defatting by a cold extraction with the chloroform‐methanol‐water (3:2:1) mixture followed by a hot extraction with 1‐propanol. A comparison of results allowed discussion of the effectiveness of the extraction procedures, their effect on the structure of original starch as well as the structure of oat starch‐lipid inclusion complexes.

Wild Yam (Dioscorea dumetorum) was collected during the wet as well as dry season in the bush of Zimbabwe. Starch from its tubers was isolated in behavioral conditions and properties were determined such as size of granules, content of water, amylose, phosphorus, proteins and lipids, characteristics of gelation of its gels and thermal properties (TG, DTG, DTA).

Kartoffelstarke enthalt chemisch gebundene Ortho-Phosphorsaure (30 bis 175 mg% P). Von den physikalisch-chemischen Eigenschaften der Kartoffelstarke, die von der Phosphorsaure bestimmt werden, sind Ionenaustausch und Selbsthydrolyse die wichtigsten. Die Fahigkeit der Kartoffelstarke zum Ionenaustausch ermoglicht die Darstellung der Salze von reinen Estern der Arnylophosphorsaure (Kationenstarken). Natrium-, Kalium-, Ammonium-, Calcium-und Magnesium-Starken unterscheiden sich in ihren rheologischen Eigenschaften. Die Wasserstoffionen der sogenannten Wasserstoffstarke konnen die hydrolytische Spaltung der Kartoffelstarke bewirken. Dabei laufen zwei Prozesse ab, und zwar die Spaltung der glucosidischen Bindungen und die Spaltung der Esterbindung zwischen der Phosphorsaure und der Glucoseeinheit. Die Geschwindigkeit der Selbsthydrolyse ist von der Wasserstoffionen-Konzentration abhangig. Die Selbsthydrolyse von Wasserstoffstarke ermoglicht die Herstellung von Starkeabbauprodukten mit unterschiedlichen anwendungstechnischen Eigenschaften ohne Verwendung von Chernikalien und/oder Enzympraparaten.On the Phoshoric Acid in Potato Starch. Potato starch contains chemically linked ortho-phosphoric acid (30 to 175 mg% P). Among the physico-chemical properties of potato starch effected by the phosphoric acid the most important are ion exchange and selfhydrolysis. By the ability ofion exchange it is possible to produce the salts of the pure esters of amylo-phosphoric acid (cationic starches). Sodium, potassium, ammonium, calcium and magnesium starches differ in rheological properties. The hydrogen ions of amylophosphoric acid are able to effect the hydrolytic splitting ofthestarch. This hydrolysisconsists of two different processes :the splitting of the glucosidic linkages and the splitting of the ester linkage between the phosphoric acid and the glucose unit. Velocity of self-hydrolysis is dependent on the hydrogen ion concentration. The self-hydrolysis of hydrogen starch offers the possibility of producing degraded starch products with different technical properties without any addition of chemicals and/or enzymes. ~~ ~ * Vortrag anlaI3lich der 31. Starke-Tagung der Arbeitsgemeinschaft Getreideforschung in Detmold vom 23. bis 25. April 1980. Starch/Starke 32 (1980) Nr. 12, S. 405-408