Adobo is not just a dish, it is a cooking method which uses a lot of souring agents to prevent meats from spoiling or decaying.
It is a very popular preservation method here in the Philippines because our climate is hot, and foods that are prepared on the table can become spoiled easily.
That's why our ancestors would marinate certain types of meat, like chicken, carabao, fish, beef and many others in a concoction of onions, garlics, peppers, salt and vinegar, so that the food can be stored for several weeks before its consumption date.
Then came the Chinese traders who introduced the use of soy sauce, which was later added to the Adobo dish that caused the darkening of the meat and sauce color.
Adobo is just one of the food preservation techniques here in the Philippines.