denatured vs rancid

[Ioanna]

For fats or proteins, denatured is usually used in a cooking context, and usually authors are suggesting a subsequent ease of digestion. Rancid is usually used in a decomposition context and usually authors are suggesting that is not fit for human consumption. 

Is there any difference in structure between a protein of fat this is 'denatured' or 'rancid'??

[Raw Kyle]

I thought that proteins become denatured as they lose their tertiary shape and begin to break down into amino acids, and fats become rancid as they oxidize or glycate.

[Ioanna]

yes, that's what I understood to be, I just recently read some things that used the terms interchangeably and to apply to both proteins and fats so I didn't know at that point what difference the author was making?  oh well, it wasn't a scientific journal or anything so maybe the author just wasn't clear.