Final answer:
A whole grain consists of the bran, endosperm, and germ. Refining grains removes the bran and germ, leading to a loss of many nutrients but an increase in shelf life and, for some, preferred baking properties. Whole grains are healthier due to their higher nutritional content.
Step-by-step explanation:
The anatomy of a whole grain comprises three main parts: the bran, the endosperm, and the germ. The bran is the outer layer providing fiber, the endosperm is the middle layer rich in starch, and the germ is the core containing nutrients. The process of refining grains typically involves removing the bran and germ during milling, which unfortunately also removes many of the nutrients present in whole grains. The endosperm, which is high in starch but lower in other nutrients, is what remains in refined grains such as white flour.
Whole grains are considered to be more beneficial to our health because they contain more fiber, protein, vitamins, and minerals compared to refined grains. Good sources of whole grains include wheat, oats, rice, barley, and quinoa. The refining process results in a product that may be less nutritious but has a longer shelf life and perhaps different baking qualities.