Peel the garlic cloves and crush them in a mortar with a pinch of salt until you achieve a paste. Set aside. Also crush the peppercorns.

In a deep tray or container, combine the sour and sweet orange juices, white wine, thyme, bay leaf, cumin, crushed garlic, salt, and olive oil. Mix well.

Puncture the pork loin with a sharp knife to allow the marinade to penetrate better. Rub the marinade over the meat with your fingers to ensure it is fully coated.

Place the pork loin in the container with the marinade, cover it with plastic wrap, or use a plastic bag to ensure the marinade covers it completely. Refrigerate overnight or, if short on time, at least 30 minutes before cooking.

Remove the pork loin from the refrigerator and pat it dry slightly. In a non-stick frying pan, sear the meat over medium-high heat until all sides are golden.

Preheat the oven to 175 °C (350 °F). Place the pork loin on a baking tray, cover it with aluminum foil, and cook for 30-35 minutes, or until the internal temperature reaches 63 °C (145 °F). Use a meat thermometer inserted into the thickest part of the loin to check.

Remove the pork loin from the oven and let it rest for 5 minutes before slicing. Serve with potatoes, vegetables, rice, fried root vegetables, or any side dish of your choice.