14B-3 |
Effect of gamma irradiation on the physicochemical properties of medicinal herbs |
K. B. SONG1, J. Lee, and N. Sun1. (1) Dept. of Food Science & Technology, Chungnam National Univ., College of Agriculture & Life Sciences, 220 Gung-dong, Yuseong-gu, Daejon, 305-764, South Korea Various medicinal herbs have been used for the treatment of many diseases in Asian countries. Ionizing radiation of herbs for sterilization has increasingly gained commercial interest since herbs have microbial spoilage during storage and ionizing radiation has become an alternative for food sanitization. In international trade, regulation has become necessary, and a detection method is needed. Our objectives were to elucidate the physicochemical change of herbs caused by irradiation, and to develop a rapid detection method for irradiated herbs. Herbs: Astragalus membranaceus Bunge, Havenia dulcis Thumb, and Rehmannia glutinosa were packed in the polyethylene bag and irradiated at 1, 5, 7, and 10 kGy using a 60Co irradiator. Viscosity was measured using a Brookfield viscometer at 30 rpm with spindle number 0. ESR was measured using an ESR X-band spectrometer. DNA comet assay was performed and the tail lengths of 100 comets in the irradiated herbs were determined. With an increasing irradiation dose up to 10 kGy, the viscosity of all samples decreased proportionally. The ESR spectral signal intensity increased with the increasing irradiation dose. DNA comet assay showed that the tails of comets became longer with increasing irradiation dose. With increasing irradiation doses, the tails of comets became longer with average tail length increasing from 17 (non-irradiated) to 124 (10 kGy) ¥ìm. Above 7 kGy, some of the tails were separated from the heads of comets. Distribution patterns of the tail length of 100 comets selected randomly in the irradiated herbs were analyzed to quantify the DNA damage. These results clearly imply that gamma irradiation affected the physicochemical properties of medicinal herbs, and viscosity measurement, ESR analysis, and DNA comet assay can be used for simple and reliable detection of irradiated herbs.
Session 14B, Food Chemistry: Physicochemical properties
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