Department of Food Science and Biotechnology, National Chung Hsing University, 250, Kuo Kuang Road, Taichung 402, Taiwan, ROC.
J Hazard Mater. 2010 Apr 15;176(1-3):280-7. doi: 10.1016/j.jhazmat.2009.11.025. Epub 2009 Nov 6.
This study investigates the feasibility of using gamma irradiation for photodegradation of a common residual fungicide, pentachloronitrobenzene (PCNB), in ginseng, and for microbial decontamination. American ginseng, Panax quinquefolius, was subjected to gamma irradiation. PCNB residues were analyzed by gas chromatography with electron capture detection and mass spectrometry. Eighty percent of PCNB (100 ppm) in a methanol aqueous solution was degraded by 5 kGy irradiation, and the primary degradation product was pentachloroaniline. Furthermore, contaminated PCNB (3.7 ppm) in ginseng were reduced to 0.2 ppm after 20 kGy irradiation. The IC(50) for treatment of Sclerotium rolfsii with 20 kGy irradiated PCNB was about 2.7 times higher than that for treatment with unirradiated PCNB. The survival rate of mouse fibroblast L929 cells treated with 20 kGy irradiated PCNB was about 12.9% higher than that of L929 cells treated with unirradiated PCNB. Additionally, after 20 kGy irradiation, less than 5% reduction of contents of ginsenoside Rb1 and Re were observed, and amounts of ginsenosides Rc, Rd, and Rg1 were not reduced significantly. The minimal gamma dose for microbial decontamination was 10 kGy. Therefore, gamma irradiation can be used for both PCNB photodegradation and microbial decontamination of ginseng without obvious loses of ginsenoside contents.
本研究探讨了伽马辐照用于降解人参中常见残留杀菌剂五氯硝基苯（PCNB）和进行微生物去污的可行性。对西洋参（Panax quinquefolius）进行了伽马辐照。采用气相色谱电子捕获检测和质谱法分析 PCNB 残留。在甲醇水溶液中，80%的 100ppm PCNB 经 5kGy 辐照即可降解，主要降解产物为五氯苯胺。此外，经 20kGy 辐照后，人参中污染的 PCNB（3.7ppm）降至 0.2ppm。用 20kGy 辐照的 PCNB 处理 Sclerotium rolfsii 的 IC50 约比未辐照的 PCNB 高 2.7 倍。经 20kGy 辐照的 PCNB 处理的小鼠成纤维细胞 L929 的存活率比未经辐照的 PCNB 高约 12.9%。此外，经 20kGy 辐照后，人参中 Rb1 和 Re 的含量仅减少不到 5%，而 Rc、Rd 和 Rg1 的含量没有明显减少。微生物去污的最小伽马剂量为 10kGy。因此，伽马辐照可用于 PCNB 光降解和人参的微生物去污，而不会明显降低人参皂甙的含量。
