MODIFICATION ON LIQUID RETENTION PROPERTY OF CASSAVA STARCH BY RADIATION GRAFTING WITH ACRYLONITRILE .1. EFFECT OF GAMMA-IRRADIATION ON GRAFTING PARAMETERS

Radiation modification on liquid retention properties of native cassava starch, gelatinized at 85-degrees-C, by graft copolymerization with acrylonitrile was carried out by mutual irradiation to gamma-rays. A thin aluminum foil was used to cover the inner wall of the reaction vessel, so that the homopolymer concentration was reduced to be less than 1.0% with a distilled water retention value of 665 g/g of the dry weight of the saponified grafted product. Confirmation of graft copolymerization and saponification reactions was made by the infrared spectrophotometric technique. The combined effect of radiation parameters in terms of an irradiation time and a dose rate to the total dose on the extent of the grafting reaction expressed in terms of grafting parameters which directly influenced liquid retention values was evaluated in conjunction with statistical analysis.