The hydrolysis of fats and oils under acidic or alkaline conditions, and the hydrolysis of fats and oils to a greater extent under alkaline conditions, is known as a saponification reaction, and sodium hydroxide is the alkaline nature of the alkali, so the addition of sodium hydroxide allows a saponification reaction to take place.

Sunflower oil, is the oil squeezed from sunflower seeds, the fruit of the sunflower.