Radiation degradation yields for some crystalline carbohydrates and distribution of the damage within the disaccharide molecule

Abstract

Crystalline carbohydrates were irradiated with 60Co γ-rays and then dissolved in oxygen-free water. The total degradation yields were determined by isotope dilution using 14C-labeled carbohydrates and synthesis of suitable derivatives. The initial G-values for total degradation were found to be 6 for sucrose, 7 for trehalose dihydrate and 8 for maltose monohydrate. D-Fructose and lactose monohydrate are highly radiation sensitive with initial G-values for total degradation of about 40 and 50, respectively. Hydrolysis of irradiated sucrose, trehalose dihydrate and maltose monohydrate followed by determination of the degradation with respect to their monosaccharide constituents shows that the radiation damage is mainly localized to one of the monosaccharide moieties of any damaged disaccharide molecule. Dissolution of irradiated α- D-glucose and lactose monohydrate in oxygenated water and subsequent determination of the total degradation indicate that the presence of oxygen in the water increases the measurable degradation.