Effect of gamma irradiation on microbial load and sensory characteristics of aniseed (Pimpinella anisum).

Seeds of anise (Pimpinella anisum) were exposed to doses of 0, 5, 10, 15 and 20kGy in a (60)Co package irradiator. Irradiated and unirradiated samples were stored at room temperature. Microbial populations on seeds, total and inorganic soluble solids in water extract and sensory properties of the latter were evaluated after 0, 6 and 12 months of storage. Results indicated that gamma irradiation reduced the aerobic plate counts of aniseed. Immediately after irradiation, the total soluble solids in an extract of irradiated seeds were greater than those of unirradiated ones. The total soluble solids in an extract of irradiated and un-irradiated seeds increased after 6 and 12 months of storage. There were no significant differences (p>0.05) in inorganic soluble solids between the water extract of irradiated and unirradiated aniseeds. Sensory evaluation indicated that gamma irradiation improved sensory characteristics of aniseed water extract tested immediately after irradiation; however, after 12 months of storage, no significant differences (p>0.05) were found in color, taste or flavor between extract of irradiated and unirradiated seeds.