[I understand the desire to have scientific knowledge and there are good resources in other comments.]
without explaining why those rules exist.
The explanation is that the rules make it taste good (or how it should taste or safe to eat or nutritious or in keeping with divine directives etc.).
Tasting good etc. is the reason for the recipe (and what tastes good etc. is literally a matter of taste or culture). Here scientific theory is post hoc. People cooked by many rules long before the coining of “bio-science.”
