RESUMEN
BACKGROUND: To retain more biological activity of organic matter and materials, it is necessary to grind and refine the pearl powder by physical method. The ball grinding method can retain the organic matter in the pearl powder and its activity to the greatest extent. The nanomaterials prepared by ball milling in different dispersion media exhibit different effects. OBJECTIVE: To compare nano-pearl powder milled with distilled water and anhydrous ethanol. METHODS: Nano-pearl powder was prepared by grinding with anhydrous ethanol and water as dispersion medium respectively. The prepared nano-pearl powder was compared by scanning electron microscope, transmission electron microscope, X-ray diffraction, Kjeldahl method and by determining amino acid content in foods. RESULTS AND CONCLUSION: (1) The nano-pearl powder prepared with anhydrous ethanol as dispersion medium was mainly round particles of different sizes (range, 30-50 nm), with the average grain size of 20 nm. The relative percentage of calcite calcium carbonate increased to 7%. The contents of protein and amino acid did not change obviously. (2) The nano-pearl powder prepared with distilled water as dispersion medium was mainly round particles of different sizes with the average grain size of 30 nm. There were irregular grain-like or block-like particles. The relative percentage of calcite calcium carbonate increased to 10%. The contents of protein and amino acid decreased. (3) These results showed that there was a significant difference in the particle size of the pearl powder ground with distilled water and anhydrous ethanol. The pearl powder prepared with anhydrous ethanol as the dispersion medium had a finer more uniform particle size.