I'm on a mission to recreate boxed mac and cheese or velveeta shells and cheese. I've used sodium citrate to make a creamy cheese emulsion from normal cheese. However, I feel that my sauce still lacks a certain tart/piquant/tangy/sour taste. I've tried adding lactic acid, and while this helps, it only adds more sour, but no "salty tang". I've read the ingredients list, but off hand can't identify the one thing that makes these "artificial" cheese sauces taste as good as they do! FWIW, obviously it is easier/cheaper to just buy these sauces off the shelf, but I'm drawn to the challenge and learning that come with replicating at home! I also understand that these sauces are industrially engineered products with many ingredients and that exact replication would take all ingredients in the original, but I have a hunch that there is a single ingredient that could take my sauce quite a bit closer in flavor. 
Cook some of each. The one that's done in 20 mins or so is bulgur. [I tend towards 1:1.6 bulgur:water, 15 mins simmer, 15 mins rest.] The one that eventually needs more water adding & takes at least another half hour is cracked wheat. …then label them ;)) Alternatively, the heat-free method. Soak both overnight in excess water. The edible one is bulgur. 