Two of the best ways to tenderize meat without a tool are thermal and enzymatic tenderization. Many chefs prefer these methods over the tenderizing tool because they break down tough connective tissue without crushing the meat fibers.
Thermal tenderization is a low-heat, long-cooking process that results in fork-tender meats. Used most often for large cuts of meat like roasts and briskets, the long cooking time allows the heat to melt the collagen. Enzymatic tenderization uses fruit enzymes in marinades to break down tough fibers. The best fruits for tenderizing are kiwi, pineapple and papaya. Papaya extract is the key ingredient in powdered meat tenderizers.