Friday, February 1, 2013
So my friend asks me - do I know if a certain favorite Chinese restaurant is MSG-free? This is a loaded question - to be honest, no restaurant is probably MSG-free. But I am getting ahead of myself. Just what is MSG anyway? The initials stand for monosodium glutamate - chemically, that breaks down into one atom of sodium and a glutamate molecule. The sodium isn't usually the relevant element; glutamate is the moiety of interest. And what is glutamate? It's an amino acid.
Let's take a quick trip to basic biochemistry. You've heard that protein is important in your diet, right? Well, that's because proteins make up a lot of the workhorse molecules that govern life itself - from enzymes, to structural materials, to regulatory switches, proteins do these things. And proteins, well, they're made of up smaller subunits called amino acids. Think Lego bricks - you can make anything from a computer to a starship with a limited set of brick shapes, it just depends on how you arrange them together. Much the same way, most life takes a basic set of 20 amino acids, hooks them up in various ways, and viola, you get hemoglobin, or puffer fish toxin, or aspartame.
Of these 20 amino acids, human can synthesize 10 - the other 10 are called the essential amino acids because they have to be procured in the food. That is, we eat proteins, break them down into the component amino acids, and then reuse them for our purposes. And glutamate? Well, we already make this amino acid in our own bodies.
The concept of umami or the flavor of "savoriness" may still sound foreign to a lot of folks as the "fifth" taste, but biochemically, we definitely have receptors for this sensation - and it is triggered by glutamate. Foods rich in protein, like broth, teem with umami because there's lots of glutamate there. Common techniques of adding mushrooms or yeast extract are simply ways of adding crude amounts of glutamate to the bolster the umami profile of a dish - after all, that is what the receptors have evolved to look for. In a sense, almost no food, so long as it has some protein in it, is free of glutamate. So, why all the fuss about MSG - which is basically just a chemically pure form of glutamate? Could it stem from the demonization of chemical purity? And why specifically the quest for MSG-free Chinese food?
Years of testing has failed to tie any particularly adverse reactions to exogenously added MSG to food, unless the tasters know about it. And this includes ridiculous amounts of added MSG. But the story is a fascinating one that inspects the American distrust of "ethnic" incursions in the 1970s, tenacious adherence to a cultural scapegoat, and is quite capably told in The MSG Files. Highly recommended reading.