Aloe has been widely used in food products, pharmaceuticals, and cosmetics because of its aromatic
and therapeutic properties. In the present study, the ethanolic extracts of aloe gel were gamma irradiated from 10 to 100 kGy. After gamma irradiation, the color of the ethanolic extracts of aloe gel
changed to red; this color persisted up to 40 kGy but disappeared above 50 kGy. Liquid chromatography /mass spectrometry analysis demonstrated the production of a new, unknown compound (m/z¼132) after gamma irradiation of the ethanolic extracts of aloe gel. The amount of this unknown
compound increased with in creasing irradiation up to 80 kGy, and it was degraded at 100 kGy. Interestingly, it was found that gamma irradiation significantly increased the antioxidant activity, as
measured by the 1,1-diphenyl-2-picrylhydrazyl-radical scavenging capacity. The antioxidant activity of
aloe extract was dramatically increased from 53.9% in the non-irradiated sample to 92.8% in the sample
irradiated at 40 kGy. This strong antioxidant activity was retained even at 100 kGy. These results
indicate that gamma irradiation of aloe extract can enhance its antioxidant activity through the
formation of a new compound. Based on these results, increased antioxidant activity of aloe extracts by
gamma rays can be applied to various industries, especially cosmetics, foodstuffs, and pharmaceuticals