Rice comes in short, medium or long kerneled varieties. Protein content of rice is lower than that of wheat and other major cereal grains. The whole (unhulled) rice kernel contains vitamins, thiamine, niacin, and rioflavin.
Rice is usually eaten as milled whole grain. Rice flour, prepared from broken grains, is used as a thickener, or a substitute flour for people with wheat and gluten allergies, and can be mixed with other flours. Rice does not contain gluten and therefore cannot be used for bread baking.
Because the milling process removes vitamins from rice and other grains, an enriched rice, whose kernels are coated with vitamins and minerals supplements, is now available. Rice is also a excellent source of high energy carbohydrates, is rich in certain essential amino acids. External layers contain vitamin B1, B2 and minerals, and therefore whole rice is nutritionally superior to white rice.
The whole grain (the paddy) is 20% hull, 13% bran, 3% polishings, 64% grain. The hull, bran, and polishings are removed from the rice and are milled. Unmilled brown rice retains the outer bran layer and much of the nutrient value of whole rice.