Originally Posted by buccaneer
Marinades don't penetrate nor do acids tenderize,except for making the outer mushy.
Papain, if not time controlled, will turn the meat to mush also.
Sorry to be the bearer of bad news but at least you have something that will tenderize.
Nothing is going to make tri tip melt literally like butter.
Acids will tenderize, but they tend to work at surface level like Bucc stated. I've done lot's of chicken with things like lime, orange juices etc. They will turn the outter surface a light gray. It also makes it slimy. It's basically cooked the outter surface. Once you grill it, that outter surface is what gives you the flavor much like a rub. But, unless I jaccard the meat, it won't really go passed the surface and the inside tastes normal. If I inject, there is much more flavor internally, BUT you need to work on a quick time line.