Gamma‐Irradiation Affects Some Physical Properties of Dry Bean ( Phaseolus vulgaris ) Starch

Gamma‐irradiated great northern (GN) bean starch (2.5–20 kGy) showed apparent increased susceptibility to central fissures. Bean damage during scanning electron microscopy was observed using ≥400OX magnification on GN bean starch samples. Approximate molecular weights estimated by gel filtration chromatography Sepharose Cl‐2B of control GN bean starch were: amylopectin >2×10 6 and amylose 2×10 5 . Amylose‐like fraction of irradiated bean starch (20 kGy) revealed two peaks ∼6.9×10 4 and 1.5×10 5 daltons. Differential scanning calorimetry showed an increase in gelatinization enthalpy and a small increase in gelatinization peak temperature at 20 kGy suggesting a reorganization of the crystalline and amorphous phases of the starch granule.