What is whole wheat flour?

Whole wheat flour: Wheat seeds consist of bran, endosperm and germ. Bran is hard and difficult to digest, and germ is rich in oil and rancidity, so flour is made of endosperm. But bran provides rich dietary fiber, which is very beneficial to human digestion. So whole wheat flour is to add ground bran to ordinary flour made of endosperm. For bread, cakes, noodles and other different uses, the proportion of bran added, the size and shape of bran are also different, so in fact, whole wheat flour is not a crude product directly ground from whole wheat grains, but a more complicated refined product.