Irradiated sorghum grain: Phytochemical, physicochemical, and functional properties

Sorghum (Sorghum bicolor L. Moench) grain is prone to microbial and insect infestation. This study evaluated some quality properties of sorghum grain irradiated with low energy electron beam (LEEB), high energy electron beam (HEEB), and gamma rays. The experimental samples were sorghum grain irradiated at 2, 4, 6, 8, and 10 kGy, while the unirradiated sample served as a control. The experiments with LEEB and HEEB involved accelerators ILU-6 (250 keV) and ELEKTRONIKA 10-10 (9 MeV), respectively. A Chamber 5000 Co-60 device provided gamma irradiation. The phytochemical, physicochemical, and functional properties were defined by standard methods. The study revealed significant (p ≤ 0.05) reductions in the total phenolic, flavonoid, and tannin contents, although they were not dose-dependent. The total phenolic contents reduced from 6.15 (control) to 3.13 GAE/g (gamma rays), 2.74 (HEEB), and 3.47 GAE/g (LEEB). The total flavonoid content reduced from 3.55 (control) to 1.83 QE/g (gamma), 1.78 (HEEB), and 1.59 QE/g (LEEB). The tannin content reduced from 11.96 (control) to 5.19 TAE/g (gamma rays), 2.58 (HEEB), and 6.17 TAE/g (LEEB). The HEEB treatment and gamma rays reduced the pasting properties whereas the LEEB method caused no significant changes. Irradiation did not change the A-type starch crystals but affected its relative crystallinity. The bulk density, oil absorption capacity, solubility index, and swelling power changed significantly after irradiation. The low energy electron beam treatment demonstrated a good potential as an alternative irradiation source for sorghum grain because it had no adverse effect on its physicochemical and functional properties.