Characterization of Fresh Cut Locally Available Vegetables Before and After Co-60 Irradiations

Abstract

Irradiation has received much attention as an effective method for food preservation and as a staple tool for assuring food safety. Thus, it is important to know how much radiation is absorbed as well as what changes are observed in food sample during the irradiation process to find minimally processed fresh foods. Fresh cut locally available vegetables, namely, potato, pumpkin, radish, elephant-yam, beetroot and sweet potato and their juices were chosen for irradiation with low dose gamma radiation from cobalt-60 source which emits photons 294.12 cC7min in air at a distance of 55 Cm from head of the source. The vegetable and juice samples were exposed to low dose radiation of 0,1, 3, 5, 9,12,15, 20, 25, and 30 ͨ ͬ in air. I-V (Current-Voltage) characteristic curves for the rectangular parallelepiped shape of irradiated samples were obtained, where the computer interfaced Keithley source meter by LabVIEW program is used. The pH values were measured for vegetable juice samples before and after irradiation. The gradient of the conductivity against the dose variation calculated for beetroot, potato, radish, pumpkin, elephant yam and sweet potato were 0.396, 0.785, 0.961, 1.081, 1.211 and 1.66 µSmˉ¹GY¹, respectively. The increasing nature of the conductivity with dose in samples appears to be due to the increasing damage of tissue membrane with dose. The radiation compensation constant calculated for beetroot, potato, radish, pumpkin, elephant yam and sweet potato were 0.006,0.012,0.024,0.02,0.043, and 0.022 GY1, respectively. The gradient of the pH variation against the dose of irradiation was calculated for radish, elephant yam, pumpkin, beetroot, and potato. The gradients were -0.00104, - 0.00133, -0.0033, -0.00435 and -0.037 GY1, respectively. A mathematical model can be predicted for the variation of conductivity of vegetables with radiation. Acidity is increased with the increased dose of irradiation due to the formation of H+.