What is the primary non carbohydrate component of fiber?

The primary non-carbohydrate component of fiber is lignin. Lignin is a complex polymer that is found in the cell walls of plants. It is a strong and rigid material that helps to protect the plant from damage. Lignin is also indigestible by humans and animals, so it passes through the digestive system undigested. This can help to add bulk to the stool and promote regularity.