Effect of gamma-irradiation on the antioxidant activity of Lukotan honey from Sierra Madre
In this study, the effect of gamma irradiation on the antioxidant properties of Lukotan honey was studied. Lukotan honey was irradiated in a Co60 irradiator to 0, 10, 20, and 30 Gy. Non-irradiated and irradiated samples underwent exhaustive extraction using solvents of increasing polarity, specifically, hexane, chloroform, ethyl acetate and water to separate the components based on their polarity. Total flavonoid content of the honey before and after irradiation was determined and expressed as mg Quercetin equivalence (QE)/100 g honey. The antioxidant activity of the crude honey and fractions (extracts) were ascertained using DPPH and Ferric Reducing Antioxidant Power (FRAP) assays while Fe(II) chelation ability was determined to the ability of the extracts to remove Fe(II) from test solutions. The results show that the total flavonoid content of Lukotan honey did not show a significant change from 0 irradiation to exposure to 30 Gy. On the other hand, antioxidant activity using the DPPH and FRAP assays of the crude extract and ethyl acetate fractions of Lukotan honey are comparable with the positive control particularly at 1000 ppm. Irradiation at doses 10-30 Gy however, decreased all antioxidant activities. At both 100 and 1000 ppm extracts, irradiation appears to have varied effects on Fe chelating activity of these samples.