Effects of electron beam irradiation on microbial load and physicochemical qualities of Ligusticum chuanxiong Hort

Ligusticum chuanxiong Hort. Is a popular traditional medicinal herb used in China, Korea and native America for centuries. Microbial contamination of herbs may cause spoilage and pose health risk to human. In this study, the effects of electron beam irradiation (EBI) on microbial load and physicochemical qualities of L. chuanxiong were investigated. Microbial load of L. chuanxiong was greatly reduced by EBI in a dose-dependent manner. Ferulic acid and levistolide A contents were not affected at 3-7 kGy. The content of 3-n-butylphathlide increased by approximately 4.1% after 5 and 7 kGy irradiation. No significant change of chlorogenic acid content (p > 0.05) was observed at 3 and 5 kGy. Senkyunolide A content was not affected and ligustilide content was slightly reduced at 7 kGy. No new volatile compound was detected after EBI. The orthogonal partial least squares discriminant analysis (OPLS-DA) showed that non-irradiated and irradiated samples located in different confined areas. Antioxidant activities of L. chuanxiong remained at high levels after irradiation. Hunter's color of the sample was slightly changed at 5 and 7 kGy. Sensory characteristics of the sample were not affected at 3 and 5 kGy irradiation. These findings indicate that a dose of 5 kGy could be suitable for irradiation of L. chuanxiong and EBI has great potential in L. chuanxiong preservation.