I'm currently letting some wild turkey (the bird, not the whiskey) marinate in some plain yogurt. I saw this somewhere on TV or online. Does anyone know what's actually going on chemically when the meat is marinating in the yogurt? Since it's a base I can't imagine that it will have much of an affect on breaking the meat do, although I could see the yogurt working its way in between muscle fibers. Anyone with experience marinating with yogurt care to comment?
The two general purposes of marinating is to tenderize and add flavor. What is happening is that the acidic elements are penetrating the meat and breaking down connective tissue. This causes the meat to become tender. Depending on your marinating liquid it also infuses flavors into the meat. I make a tandoori chicken recipe that calls for plain yogurt and spices. The flavor change will be minimal if you are using only plain unflavored yogurt. Here is an article that I found that goes into a little detail. Marinade Science Article