Definitely keeps the protein. I think drastic temperature changes can affect food but I doubt it can go as far as destroying large amounts of nutrients. I’ve heard microwaves aren’t great for food but haven’t looked into it so take that with a grain of salt!
Nope. After 8 hours in the fridge meat loses all it’s protein. And since it’s mostly protein all you’re left with is a little pile of fat. Makes it really hard to store stuff like salami and cold cuts. Keeps disappearing. There are various theories on where the protein goes, but most people think it’s consumed by microscopic protein elves that live in the back of the meat drawer. True fact.