While varying by the cooking method and particular recipe, common ingredients used to cook a pork loin include oil, an acid, and herb or seasoning mixtures. Pork loin supports roasting, broiling, slow cooking, brining and grilling, and requires additions appropriate for those styles.
Some ingredients form a crust during cooking that prevents the meat from drying out and intensifies the flavor. The Food Network provides a simple roasted recipe that entails searing the meat in 1 tablespoon vegetable oil, salt and pepper, and rubbing the pork with 2 tablespoons cider vinegar and dried mustard for roasting.
Other ingredients combine to create a marinade that performs a similar function. All Recipes suggests using 1/2 cup balsamic vinegar, 2 tablespoons steak seasoning rub and 1/2 cup olive oil as a marinade in its Balsamic Roasted Pork Loin recipe.
Brining uses supersaturated solutions of salt or sugar and liquids to increase the meat's moisture retention before roasting, smoking or grilling. A standard brine recipe uses 1 cup salt to each 1 gallon of water. Kosher salt contains less mass per volume, and should be increased to 1 1/2 cup per gallon. In any recipe, timing is critical, since over-brining leads to inedible pork. The meat also cooks faster after brining.