The endosperm of the seed has two parts. The bulk of the volume is a starch storage area. The covering layer is called the aleurone layer. The aleurone is made of cells that store protein in abundance.
You probably know about this in the case of rice. Rice grains are treated before we buy them for cooking. The fruit/seed coat is milled off and discarded as it has little food value. The embryo breaks out and is called the "germ." In wheat, the embryos are sold as wheat germ. The milling process leaves the rice endosperm surrounded by aleurone. This is sold as brown rice and has food value in starch and protein. It has an interesting texture after cooking. If the endosperm is polished before it is sold, the aleurone can be removed. Polishing results in white rice which has food value in starch only. Thus white rice, while considered much "finer" than brown rice, is actually a lower-quality food.
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