Assessing Impact of Gamma Irradiation on Proximate Composition of White Yam, Dioscorea Rotundata: Pepa Specie Farmed in Nasarawa State
Previous attempts by Nigeria to export yams have not yielded the desired objectives because the yams were rejected due to rot, before reaching their destination. On the basis of the foregoing attempt was made to evaluate the impact of gamma irradiation on the proximate composition of the local Pepa yam, variety of the white yam; Dioscerea Rotundata. This was to determine the preservation ability of gamma radiation source and its durability. Pepa yam tubers were gathered from six Local Government Areas (LGA) of Nasarawa State using the judgmental sampling method. The irradiation was carried out using Co- 60 source at the Gamma Irradiation Facility of the Nigeria Atomic Energy Commission (NAEC), Abuja, F.C.T. The irradiation processing was done at varying dose rates with the dose limits ranging from 30Gy, 60Gy, 80Gy, 120Gy, 150Gy, 180Gy, 230Gy and 300Gy. The samples were stored for 5 months at ambient temperature in a room with the floor covered with sand. The proximate compositions of the irradiated samples were analyzed using the standard methods of the Association of the Official Analytical Chemistry and resulting data processed with SPSS ANOVA using repeated measure t-test. This is to test for the measure of significance between values of the proximate composition immediately after irradiation (IAI) and five months after irradiation (A5M). Pearson Correlation was also performed to ascertain the relationships between the variables. Measured variables of the proximate compositions: crude ash, crude fat, crude protein, crude fibre, carbohydrate, revealed a statistically significant positive correlation p < 0.01 between the Pepayam samples immediately after irradiation and 5 months later. This indicates that there is a relationship between the irradiation and the changes in the values of the proximate compositions and longevity in terms of the extended shelf-life of the Pepa yams.