While I've never tried keeping large amounts of potatoes, I think you could either sprinkle a small amount of lemon juice or vinegar to the potatoes before freezing them to keep them from turning black (the same way a little is sprinkled over potatoes to keep them white when making large batches of potato salad).
I also looked up freezing potatoes in my book - it said you could do either of the above or else blanch the potatoes after shredding or cutting into cubes. (Blanching means to dip in hot water - usually in a basket, but you can also use a slotted spoon). It recommended 8-12 minutes per pound & then freezing immediately in an airtight container.
Good luck! Supposedly they still taste the same even if they've oxidized to a black color - hmmmm... maybe you could tell your hubby they're really those funny purple-blue ones?
