What is the difference between Lime & Lemon?
I have never tried it, or wanted to. I would suggest to you to scoop out some ot the potatoes, and stir in a little of the lime and have a taste to see what it is like, and then if you like it, add some at a time to the pot and check it out as you mix and stir. Be cautious not to use too much as the zest could be rather strong. Hman
Lime doesn't go well with starches. Only squeezing into cooked rice. Lime is better with fresh veggies or on Tia dishes.
I've never tried it, never heard of it, but I happen to be nuts for lime in general. If I tried it, I'd experiment first. Make a batch of standard mashed potatoes, take out a spoonful and put a squeeze of lime juice on it and try it - just a drop, then maybe another and another until you get the right amount and see if you like it at all. Actually maybe limeade would be better because of the sugar. Then if you don't like it you can eat the regular potatoes and drink the limeade.
Unlike lemon, lime has a tendency to turn bitter when heated. Therefore, the sweeteners in your recipe are used. Both agar and sugar are sweet. The agar will help to counterbalance the bitterness. Because of the milk used in mashed potatoes it is probably best to try this on plain boiled potatoes. Greek and Italian cooks have featured lemon with potatoes for centuries, so why not lime? Sounds great!