EFFETS DE L’IRRADIATION AUX RAYONS GAMMA SUR LA CONSERVATION DU BROCOLI (Brassica oleracea var. Italica)

Abstract

The objectives of the present study were to evaluate the effect of different doses of irradiation on broccoli tissues during subsequent storage, to establish whether a 1 kGy dose was detrimental to the tissue, and to describe the effects at higher doses. Irradiation strongly stimulated respiration, even at 1 kGy, in proportion to the applied dose. This enhancement reached 70% at 5 kGy. The rate of respiration of control and irradiated samples decreased during the 7 wk of storage, but that of the irradiated samples remained higher than that of the control throughout the experiment. Yellowing of the inflorescence, as measured by the Gardner colorimeter, was strongly accelerated at 1 kGy. Chlorophyll loss was greater in the irradiated samples than in the control, in the inflorescence, and even more in the stems. The general appearance of the flower heads (yellowing, bud opening) confirmed that irradiation at 1 kGy accelerated maturation of broccoli. This dose is less than that generally required for control of surface microorganisms of horticultural crops during storage.Key words: Broccoli, Brassica oleracea, irradiation, gamma rays, chlorophyll, storage