What characteristic defines unrefined grains?

Unrefined grains are characterized by their ability to retain all parts of the grain kernel, which includes the bran, germ, and endosperm. This preservation ensures that unrefined grains are rich in nutrients such as fiber, vitamins, and minerals that are typically found in the bran and germ. Consequently, these grains offer a more complete nutritional profile compared to refined grains, which have been processed to remove these vital components, often resulting in a loss of fiber and essential nutrients.

In contrast, refined grains consist primarily of the endosperm and lack many of the beneficial components found in the whole grain. The other options refer to characteristics that do not pertain to unrefined grains. Unrefined grains generally have a shorter shelf life compared to refined grains due to the natural oils found in the germ, which can go rancid. Additionally, the stripping away of fiber and vitamins is a defining trait of refined grains, not unrefined ones, which are valued for their wholesome content.