The best stuff is aged for 3 years, although you can still buy Parmigiano-Reggiano aged for 1 year and it still beats the crap out of the fake stuff. Parmigiano-Reggiano, aside from the geographic limitations as you've noted, also needs to be aged a minimum one year and use unpasteurized milk in order to be recognized as Parmigiano-Reggiano
Parmesan. According to the FDA, anything labeled "Parmesan," "Parmigiano," or "reggiano" is characterized as a cheese made from cow's milk with a "granular texture and hard and brittle rind.". Rennet, which is an animal protein or "milk-clotting enzyme that produces curd formation," is also present in the cheese, thusSo, if you were hoping to make any of these cheeses without getting out there and buying some rennet, we have bad news for you. Cheeses that are made using animal-based rennet. Mimolette. Parmesan cheese. Pecorino Romano. Gruyère. Parmigiano Reggiano. Vacherin.
Peptides derived from casein proteolysis as a marker of ripening were analyzed in cheeses like Grana Padano [119,157] and Parmigiano Reggiano [158] [159][160] and also phosphopeptides are well 2EgZ.