I was thinking you made a spelling error and wanted to know the flavour of flour... But clearly, I was wrong in this assumption.
But, if you mix flour with water it gets a sticky consistency, and the smell, well, it's vaguely familiar... So just to throw the spanner in the works... you see if you can guess what the 'protein' smell of flour resembles...
PS - Protein was the hint...
PPS - I actually don't know about the flavour of 4. But seeing as you asked, why didn't you ask the flavour of 1, 2 or 3 first? Surely 4 is for professionals only?
PPPS - Counting used to be done in 'foods' - so for example, a cow had several eating parts - so lets say (just for arguments sake only) that you only ate the legs of cows - then a cow would instantly equal 4. So the flavour of 4 could be legs....
PPPPS - Things that weren't edible weren't given a number at all... The flavour of zero.
PPPPPS - A herd of cows would go up in multiples of 'foods' - so if (back for arguments sake) legs were the case and there were 10 cows.... Then the number of cows would actually equal 40... So the number 40 tastes like a leg banquet.
I hope I answered some of your questions and also made you put some flour and water together to sniff the proteins...