Yes, if it comes into contact with the air, the surface of braised pork ribs will naturally be contaminated with microorganisms in the air, so that microorganisms will multiply on its surface, which will naturally destroy the microstructure of the surface of braised pork ribs and thus affect the color.

If you put it in the refrigerator, the oil will condense on the surface of braised pork ribs because of the low temperature, which will naturally affect its color.