Fellow THF Members,
My FIL shot a hog that was at the deer feeder. It should be corn fed.
How do you all marinate your backstraps to tenderize them?
He normally cooks them on the grill. He will split them open (butterfly)
and fill them up with onions, mushrooms, jalapenos, cream cheese and
seasoning but his biggest issue is to get those backstraps tender. So please
provide details on what and how you marinate the backstraps before cooking.
Thanks for your help and ideas.

Pineapple Juice has natural meat tenderizers in it. The Bromaline is what tenderizes the meat, it is destroyed by heat, so pasteurized pineapple juice is no good. Also do not cook your marinade.

Pineapple and soy sauce give kind of a teriyaki flavor. I would split them open and marinate in pineapple juice, soy sauce, garlic and ginger. Wrap them in bacon and cook them low and slow on the smoker.

Pineapple Juice is acidic, so use a glass bowl.

I've cooked them in a pressure cooker and they don't get tender. I've slow-cooked them overnight in a crock pot and they don't get tender. I've diced them and stewed them in green chili sauce and they don't get tender but edible because they are in small chunks. I've mechanically tenderized them and cooked them like chicken-fried steak and they are ok. I've given up after all those attempts and now I just run them through a grinder and either turn them into sausage or use as ground meat.

I'm interested and following to see if anyone has found something that works.

Paul Newman's Family Recipe Italian salad dressing.

I have started letting mine "age" in the fridge 3-5 days before trimming the fat etc... so far seems like it has worked pretty well

My wife gets our hog back straps tender. She marinates them overnight in Dale’s Low Sodium Steak Seasoning (buys it on Amazon) , browns some onions and wraps it and the backstrap in foil and cooks it in the oven till it reaches 165 degrees. She does the same (except for the foil) for pork roasts in the crock pot.

And maybe the most important thing is to get a young hog, preferably a female.

Since backstraps lack connective tissue and fat (if cleaned well), they can dry out no matter what you do in a long-cooking situation like a crock pot or pressure cooker, just as a deer backstrap or beef filet would.

If you want tender, slow-cooked meat, use shoulder, shanks, belly meat or hindquarters that are higher in collagen (silverskin) and fat. These cuts would be similar in composition to brisket and ribs.

For the OP, marinades won't typically tenderize unless there's a component that will break down enzymes, like pineapple (mentioned above) or acidulated dairy like yogurt or buttermilk, which works really well for tenderizing and doesn't convey a lot of flavor. Adding sugar (like honey, maple, bottled BBQ sauces) and oil to marinades can help with the outside sear by improving the caramelization of the exterior. I think marinades mostly improve exterior flavor and texture rather than flavor the entire cut. Brines (salt+water solution, maybe with sugar added) do more to flavor cuts like backstraps throughout and can be used in conjunction with marinades to get flavor and texture on leaner cuts.

Slice them into chop size, pound them out flat, roll in flour seasoned with salt, pepper, and italian seasoning. Chicken fry it in oil.

That's a great point Jesse. Once I started braising and slow cooking my deer shanks in a dutch oven it changed my life. I always save the shanks for braising now. I'll try it with some hog shanks next time I get one.

With my deer backstraps I cook them on the grill rare or medium rare and they don't get tough. I'm not willing to try medium rare feral hog so I grind them. I need to get myself a copy of your book I guess and explore some different ways to prepare hog backstrap.

I typically just grill the backstraps with some Tony C's and black pepper and it isn't too tough. Trimming down some of the excess fat to get a good consistent cook definitely helps. Putting a shoulder in a slow cooker with some potatoes, onions, and bell pepper is a good tender roast. Interested to see other responses

I've actuallyl had pretty good luck using a pressure cooker, but I'm usually doing it to make stew or something similar rather than serving a piece of backstrap as a n entree.
I have made rouladen using the recipe from The Hog Book and it's turned out well, but in that case I'm slicing the backstraps into fairly thin pieces and then pounding them even thinner.

i marinade in italian salad dressing then cut them into thin steaks and chicken fry them

Thanks everyone for taking the time to provide feedback and comments.

I use one of these to tenderize pretty much everything (steaks, roasts, backstraps, etc..etc..)

https://www.cabelas.com/shop/en/jaccard-super-meat-tenderizers

specifically for wild hog backstraps, I typically marinade in a mix of worcestershire sauce, minced garlic, and hot BBQ sauce.. I just seal the backstrap up in a 1 gallon zip lock with the liquid inside, throw it in the fridge for a day, then put it on the grill the following evening...

Dale's steak marinade works great for a quick marinade, just don't go over 30 minutes or it will be very salty.

They will be pretty tender already

I like Italian dressing, soy and mustard.