When sourcing Konjac Powder (Glucomannan), you must prioritize Glucomannan content, which should ideally be above 90% for high-grade applications. Pay close attention to viscosity levels, typically measured in mPa.s; high-quality powder should range between 20,000 to 40,000 mPa.s. Additionally, verify the mesh size (e.g., 120-200 mesh) to ensure it meets your specific solubility and texture requirements. For safety, ensure sulfur dioxide (SO2) levels are below 30ppm and heavy metals like Lead (Pb) are under 0.5mg/kg.