Objective To investigate the effects of calcination temperature on the phase composition and chemical constituents of Shijueming (Haliotidis Concha, HC), optimize its processing methodology, and conduct comparative analysis and health risk assessment of heavy metal content in HC and calcined HC. Methods Thermal effects during processing at different calcination temperatures were examined via thermogravimetric-differential thermal analysis (TG-DTA). Primary phase transformations were analyzed using X-ray diffraction (XRD), while compositional changes were assessed by Fourier transform infrared spectroscopy (FTIR) to preliminarily screen the key factor “calcination temperature” affecting HC processing. Simultaneously, the optimal processing parameters for HC were determined using the AHP-CRITIC mixed entropy method combined with orthogonal experiments, with CaCO₃ content, crispness, and color as evaluation criteria. Calcined HC were processed according to the optimized method. Inductively coupled plasma mass spectrometry (ICP-MS) was employed to analyze 20 batches of HC and calcined HC for Pb, Cd, As, Hg, and Cu in 20 batches of HC and calcined calcined HC. Using HC powder as a reference, theoretical maximum limits for these five heavy metals and toxic elements were calculated. Daily exposure and target hazard quotient (THQ) were further assessed to evaluate health risks, providing a reference for quality and safety evaluation of HC. Results Preliminary screening of calcination temperatures indicated an optimal range of 400—600 ℃. Using the AHP-CRITIC mixed entropy method, the optimized calcination process for HC was determined as follows: Crush HC to a particle size < 1 cm, place in a muffle furnace, set the temperature to 600 ℃, and calcine for 90 min. After calcination, the organic matter content of HC decreased while calcium carbonate content increased. The calcined HC showed reduced levels of As and Hg, with minimal changes in Cu, Cd and Pb. Health risk assessment indicated that all 20 batches of HC and calcined HC posed no significant health hazards to humans. Notably, the As and Hg levels in the slices were significantly lower than those in the raw material (P < 0.05). Conclusion By integrating phase and compositional changes before and after processing, this study employed the AHP-CRITIC mixed entropy method to scientifically and comprehensively optimize the calcination process for HC. The screening results are scientifically reliable, providing new scientific evidence for quality management and clinical application of HC and calcined HC. Conducting health risk assessments of heavy metals and harmful elements in HC before and after processing provides reference for the safe clinical use of HC and other shell-derived Chinese medicinal materials.

Haliotidis Concha  /  calcination processing technology  /  health risk assessment  /  AHP-CRITIC mixed entropy method  /  heavy metals  /  harmful elements  /  thermogravimetric-differential thermal analysis  /  inductively coupled plasma mass spectrometry  /  target hazard coefficient  /  Pb  /  Cd  /  As  /  Hg  /  Cu