• Remove any dirt, outer dry skins, and foreign matter.
• Use potable water and ensure proper hygiene.
• In commercial units, bubble washing or spray washing systems are used.

• Peel off the outer skin manually or using automated onion peeling machines.
• In some cases, steam peeling is used for large-scale production.

• Onions are sliced or chopped to the desired size depending on final product type:
  • Flakes (5–15 mm)
  • Chopped (3–5 mm)
  • Minced (1–3 mm)
  • Granules/Powder (<1 mm)
• Note: Uniform size ensures even drying.

• Light blanching may be done to inactivate enzymes and preserve color.
• Time: 1–2 minutes in hot water (85–90°C), followed by immediate cooling.
• Note: Blanching is skipped in some commercial units to retain pungency.

• Place onions in trays or conveyors in a hot air dryer or solar tunnel dryer.
• Temperature: 55–65°C
• Time: 6–12 hours depending on slice thickness and dryer type.
• Final moisture content should be below 6%.

Common Dryer Types

• Tray dryers
• Belt/conveyor dryers (for large scale)
• Fluidized bed dryers (for diced/onion powder)
• Solar dryers (for small-scale, eco-friendly production)