Reconstituted steaks, fillets, roasts, or cutlets - Meat glue is added to disparate chunks of meat (like cheap stew meat, chunks of chicken – any meat, really) and rubbed in. The chunks are compressed together and left to cool; after several hours, the meat pieces have formed insoluble bonds made of protein polymers. You can usually pull apart the “steak” to reveal the composite pieces, but take a quick glance and you’d never know it was cheap stew meat glued together. To most consumers, the resultant reconstituted “steak” is indistinguishable from a real slab of meat once it’s cooked, but a skilled meat glue artist can create “steaks” that fool experts – even when they’re raw.
http://www.marksdailyapple.com/meat-glue-separating-fact-from-fiction/
