I own a restaurant and we make a ton of potato pancakes. How do we keep 30 pounds of shredded potatoes from turning dark while storing them?
Exposure to air or oxygen is the cause of this situation when the potatoes are cut and stored in advance for any future cooking. The simplest and most effective method to prevent discoloration in prepping potatoes is this formula: Add one teaspoon of concentrated lemon juice or white wine vinegar for every gallon of water. This will minimize discoloration.
Here are a few Dr. Potato Blogs on the subject:
How Long Can Peeled Idaho® Potatoes Sit in Water?