You can file this one in the random thoughts file ;-)
Think about foods you tend to overeat once you have some. Nuts come to mind. They are usually salted, and something about the yummy nut flavor mixed with the salt seems to stay on the tongue longer. It lingers. I know that if I'm having cashews (yes, I know, not technically a nut) I want more and more and more if there is a ready supply of more. So I tend to grab nuts, when I do, in single serve packets or on the way out the door. If I have them in the house, I take a handful or whatever from the kitchen and go eat in another room. But when that handful is done, while that flavor persists in my mouth, I always want more, and it's not hunger or craving or any desire to binge. It seems to be the lingering flavor. (Brushing one's teeth helps with this big time!)
So I was thinking about something else the other day. It's soup/stew season here and I make bone broth soups/stews and slow cooked fatty cuts like chuck and pork butt. When I make these, even though I take out any large visible fat chunks, there's a lot that only partially renders out when cooking. This separates out in the soup/stew. I chill mine in those large quart containers like you get soup in at the Chinese restaurant and ... skim that fat off the top. Not because I'm fat phobic, but because I just don't like greasy soup. I tend to think my creations are rather lower if not outright low in fat by the time I'm done with them, though nowhere near the watery yuck that you get out of a can for low fat soups. These are hearty soups, one small bowl and I'm good for hours on end. Even if you were to thicken them before skimming, the fat will separate out when reheated. Now next time you're in the store go read the nutritional info on some of the hearty canned soups, stews and chili. Fatty! How can there be all that fat in there w/o it being a greasy mess?
Emulsifiers and stabilizers, that's how. Simply put, an emulsifier is a molecule that can attach to both oil and water molecules. Lecithin is the natural emulsifier in egg yolks, and it is largely responsible for mayo being one phase. Without that, no matter how finely you drizzled oil into water, no matter how fast you blended the mess, the oil and water would eventually separate. But mayo? Unless you leave the jar out in a warm room for a long while, it stays mayo. How about creamy sauces? I admit to being an Alfredo/carbonarra lover, and one of my favorite cheats is to get that from one of a few restaurants in the area. We've made our own a few times too. When you reheat these dishes a huge amount of oil separates from the sauce. But you can buy an Alfredo in a jar that doesn't do that when you heat it up. Why? Something in it keeps it "stable".
The reality is that processed/prepared foods are full of stabilizers and such to keep them from turning into greasy inedible messes when reheated. And the fat is really what carries a lot of the flavors in these foods. So I think about our tongues and mouths and that's a watery environment. Do you suppose those emulsifiers and stabilizers help these foods coat our tongues and stick around a little longer with their attached flavors? Maybe!