Effects of Electron Beam Irradiation Sterilization on Quality of Edible Kudzu Root Powder

To study the effects of electron beam irradiation on the quality of edible kudzu root powder, edible kudzu root powder was irradiated by electron beam of different doses (0, 2.5, 5.0, 7.5, 10.0 and 12.5 kGy), and sterilization effects, nutritional and functional activities and physical properties were investigated. The results showed that electron beam irradiation obviously bactericidal effect on edible kudzu root powder and the microbial survival decreased significantly with increasing of irradiation dose, the D₁₀ value of aerobic plate count was 2.68 kGy. Different doses of electron beam irradiation had no obvious effects on general nutrients including moisture, ash, protein, starch, vitamin B₁ and B_2, isoflavones including puerarin, daidzein, genistin, and ·OH radical scavenging activitiy in edible kudzu root powder (P>0.05). After irradiation, the fat content increased significantly (P<0.05), while dietary fiber content, whiteness, DPPH radical scavenging activity and reducing power decreased (P<0.05), but the overall change was not too big. The polysaccharide content, solubility and swelling force significantly increased (P<0.05), and the freeze-thaw stability was significantly enhanced (P<0.05). Therefore, electron beam irradiation was an effective sterilization method for edible kudzu root powder, the doses within 12.5 kGy wouldn't cause obvious damage to its nutritional quality and functional composition, and was expected to improve its physical properties as food processing raw materials. This study would provide a theoretical reference for the control of microorganism in edible kudzu root powder and products processed by electron beam irradiation.