bacon wrote:I bought some Queso Blanco at a local store several weeks ago. Had no idea what type of cheese it was, just looked good and, well, I like cheese. Anyway, I made a toasted sandwich with it and it didn't melt! All I could think was that it must have been something either wrong in the way I was trying to toast my sandwich or the cheese was some kind of cheapo processed stuff that wouldn't melt if you put a flame thrower to it.
*Warning: Dull polymer chemistry*
It may have been that the cheese was heat-treated previously. If it was then the protein chains may have cross-linked and become fixed so it wouldn't melt again.
Essentially, the protein chains would have been like spaghetti strands, long and flobbly. When you melt cheese they can flow over each other well, leading to the runny gunk that other people seem to like. When that cools and solidifies the protein chains can link to other chains, forming something like a big tangle of string. If you heat that the chains are attached to each other and can't move, hence it doesn't melt.
The same principle is used in vulcanising rubber. Natural rubber is runny, adding sulfur (FSM, I hate that spelling, stupid IUPAC) forms cross-links between the rubber chains and you get the useful stuff that doesn't melt in the sun.
*End of dull polymer chemistry*