Why does cooking tomato sauce change its taste?
 

Does anybody happen to know anything about taco sauce?

I scored 30 pounds of Taco John's mild taco sauce recently when one of
the local food banks ceased operation.


I decided to use some of that, instead of enchilada sauce when I made
a big pot of chicken pozole yesterday.


I tasted the taco sauce before using it and I thought that it tasted
too much like tomatoes and was too vinegary.


But after simmering the sauce for an hour, it doesn't taste like
tomatoes any more.


What I want to know is *why*?