Browsing by Author "Lemu Tammene"

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    Determination of Iron-, Zlnc-, Copper-. Calcium-and Magnezium - Binding by Procyanidins from Bird-Resistant and Non-Bird-Resistant Sorghum Grain
    (Addis Ababa Universty, 1987-06) Lemu Tammene; Chandravanshi B.S. (PhD)
    Divalent -Fe, -Zn, -Cu, -Ca, and -Mg binding by Sorghum procyanidins'(soluble and insoluble) has been investigated. Both the soluble and insoluble fractions of procyanidins bound Fe. Zn, and Cu, D~t not Ca and Mg. Binding of the cations by the insoluble procyanidins has been estimated as the difference in binding between the Bird-Resistant (BR) and Non-Bird-Resistant (NBR) NDP. Binding of Fe, Zn, and CU by procyanidins was found to depend on pH, cation concentration, amount of fiber, fiber particle size, and presence of competing cations. The Binding of NDF from twenty one lines of sorghum (16 BR and 5 NBR) was determined under optimal conditions. n new procedure was proposed to study mineral binding by soluble sorghum procyanidins based on dialysis. Cation binding by the soluble procyanidins was determined based on tho difference in cation concentration of the control and the cation solution enuilibrated with the procyanidin solutio~ (after dialysis). The trac" element cations were bound by soluble procyanidins according to the order· Fe > Zn , Cu A chelatc structure consisting of two fivemembered rings has heen proposed for the cation (Fe, Zn, eu) - procyanidin complexes.