Optimize the Instantaneous High Temperature Sterilization Process of Ilex kudingcha Based on Multiple Index Analysis

To optimize the instantaneous high-temperature sterilization process parameters of Ilex kudingcha based on multiple indicators. The process parameters of instantaneous high-temperature sterilization of Ilex kudingcha were optimized by using the orthogonal design multi-index comprehensive weighted scoring method. Sterilization temperature, sterilization time, and particle size of herbs were used as the investigating factors, the sterilization rate, IC₅₀ value of antioxidant activity of 1,1-diphenyl-2-picrylhydrazyl (DPPH·), and polyphenolic content were used as indicators, visual and ANOVA results were used to evaluate the effect of sterilization on the three examined indicators. Fingerprint technology was used to evaluate the samples before and after sterilization. The results showed that sterilization temperature was a factor that had a significant impact (P<0.05), and the optimal sterilization process conditions were as follows: Sterilization temperature 160 ℃, sterilization time 10 s, grinding size 24 mesh. No significant effect of instantaneous high-temperature sterilization on IC₅₀ values of DPPH· antioxidant activity and content of polyphenolic compounds (P>0.05). The microbiological limits of the three batches of samples sterilized by the optimized process were all in accordance with the provisions of pharmacopoeia. The IC₅₀ values of DPPH· antioxidant activity of the three batches of samples after sterilization decreased by 0.19 and the polyphenolic content increased by about 0.14% compared to that before sterilization. The results of DPPH· antioxidant activity IC₅₀ values and polyphenolic compounds content of the three batches of samples before and after sterilization were not significantly different by t-test (P>0.05). The similarity of sample fingerprint before and after sterilization was >0.9. In conclusion, instantaneous high temperature sterilization had no effect on the quality of Ilex kudingcha, which would provide experimental basis for the application of instantaneous high temperature sterilization technology in Ilex kudingcha sterilization.