I recently was making a round roast for an extended family dinner. I wanted to use a sous vide method, but when I looked at the available recipes, the cook time was 30 hours to break down the collagen for a tender roast. This was a little longer than the time I had available and also more time than I wanted to devote to the project.
I have found that when I cook a steak or filet, I can improve the texture by adding a small amount of meat tenderizer to the cooking bag before cooking. I'm not a purist, so I tend to do whatever works. Well, a round roast is a tough cut, but it's still beef. It needs some special attention if it's to be tender and flavorful. Why not use a similar method? But the roast is a much thicker cut and the tenderizer might not penetrate in the cooking time.
I used a turkey baster and filled it with about an ounce and a half of water with a teaspoon of meat tenderizer dissolved in it. I injected the solution into the roast at about a half dozen places in the face of the roast, pulling the syringe out as I injected to distribute the liquid. I then placed the roast in a bag with a touch of olive oil and a little pepper, and cooked it for three hours at 134 degrees, enough time for the roast to reach an even temperature throughout, but not sufficient to tenderize.
When the rest of the meal was almost finished, I put the roast in a 475 degree oven for 15 minutes to brown. Then I gave it a few minutes to rest while the remainder of the meal cooked, and I carved it. My company remarked that they had never had as good a roast.