Uses of Caustic Soda in Food Processing

Proper concentrations for peeling fruits, making pretzels, or cocoa
processing.
Using Sodium Hydroxide (NaOH) in Food Processing
Sodium hydroxide (NaOH) is used in food processing for peeling fruits, making
pretzels, and cocoa processing. It must be used in precise concentrations
and handled with care to ensure safety.
1. Peeling Fruits & Vegetables (Tomatoes, Potatoes, Peaches, etc.)
Purpose: Softens and loosens the outer skin for easy removal.
Concentration:
• 1–2% NaOH solution (10–20g NaOH per liter of water)
Procedure:
1. 2. 3. 4. Heat the NaOH solution to 80–100°C (176–212°F).
Submerge fruits or vegetables for 30 seconds to 2 minutes, depending on
thickness.
Remove and rinse immediately in cold water to stop the reaction.
Peel off the loosened skin manually or with water jets.
✅ Commonly Used For:
• Tomatoes, potatoes, peaches, and almonds (for blanching).
2. Pretzel Making (Lye Dipping for Color & Texture)
Purpose: Gives pretzels their dark brown, glossy crust and unique flavor.
Concentration:
• 3–4% NaOH solution (30–40g NaOH per liter of water)
Procedure:
1. 2. 3. 4. Prepare a warm NaOH bath (50–60°C / 122–140°F).
Dip shaped pretzels in the solution for 10–30 seconds.
Remove with a slotted spoon and drain excess liquid.
Sprinkle with salt and bake at high temperature (~220°C / 428°F).
✅ Safety Tip: Use food-grade NaOH and gloves to prevent skin burns.
3. Cocoa Processing (Dutch-Processed Cocoa)
Purpose: Reduces acidity, darkens cocoa powder, and enhances flavor.
Concentration:
• 1–2% NaOH solution (10–20g NaOH per liter of water)
Procedure:
1. Cocoa beans are soaked or sprayed with the NaOH solution.
2. 3. The alkali reacts with natural acids, reducing bitterness.
Beans are dried, roasted, and ground into cocoa powder.
✅ Used in:
• Chocolate and cocoa powder for baking and drinks.
General Safety Tips for Food Use of NaOH
• Use only food-grade NaOH.
• Handle with gloves and eye protection.
• Rinse all treated foods thoroughly to remove residual lye.
• Store NaOH in a dry, airtight container away from moisture.