Refined grains, in contrast to whole grains, refers to grain products consisting of grains or grain flours that have been significantly modified from their natural composition. The modification process generally involves the mechanical removal of bran and germ, either through grinding or selective sifting. Further refining includes mixing, bleaching, and brominating; additionally, thiamin, riboflavin, niacin, and iron are often added back in to nutritionally enrich the product. Because the added nutrients represent a fraction of the nutrients removed, refined grains are considered nutritionally inferior to whole grains. However, for some grains the removal of fiber coupled with fine grinding results in a slightly higher availability of grain energy for use by the body. Furthermore, in the special case of maize, the process of nixtamalization (a chemical form of refinement) yields a considerable improvement in the bioavailability of niacin, thereby preventing pellagra in diets consisting largely of maize products.
| Wheat | Rice | |||||
|---|---|---|---|---|---|---|
| Whole | Refined | Enriched | Whole | Refined | Enriched | |
| Food energy | 100% | 107% | 107% | 100% | 99% | 99% |
| Carbohydrates | 100% | 105% | 105% | 100% | 104% | 104% |
| Fiber | 100% | 22% | 22% | 100% | 37% | 37% |
| Protein | 100% | 75% | 75% | 100% | 90% | 90% |
| Thiamin (B1) | 100% | 27% | 176% | 100% | 17% | 144% |
| Riboflavin (B2) | 100% | 19% | 230% | 100% | 53% | 53% |
| Niacin (B3) | 100% | 20% | 93% | 100% | 31% | 82% |
| Pantothenic Acid (B5) | 100% | 43% | 43% | 100% | 68% | 68% |
| Pyridoxine (B6) | 100% | 13% | 13% | 100% | 32% | 32% |
| Folate (B9) | 100% | 59% | 350% | 100% | 40% | 1155% |
| Vitamin E | 100% | 5% | 5% | 100% | 18% | 18% |
| Calcium | 100% | 44% | 44% | 100% | 100% | 100% |
| Iron | 100% | 30% | 120% | 100% | 54% | 293% |
| Magnesium | 100% | 16% | 16% | 100% | 17% | 17% |
| Phosphorus | 100% | 31% | 31% | 100% | 35% | 35% |
| Potassium | 100% | 26% | 26% | 100% | 52% | 52% |
| Sodium | 100% | 40% | 40% | 100% | 71% | 71% |
| Zinc | 100% | 24% | 24% | 100% | 29% | 29% |
| Copper | 100% | 38% | 38% | 100% | 79% | 79% |
| Manganese | 100% | 18% | 18% | 100% | 29% | 29% |
| Selenium | 100% | 48% | 48% | 100% | 65% | 65% |
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Famous quotes containing the words refined and/or grains:
“The most refined skills of color printing, the intricate techniques of wide-angle photography, provide us pictures of trivia bigger and more real than life. We forget that we see trivia and notice only that the reproduction is so good. Man fulfils his dream and by photographic magic produces a precise image of the Grand Canyon. The result is not that he adores nature or beauty the more. Instead he adores his camera—and himself.”
—Daniel J. Boorstin (b. 1914)
“Little drops of water,
Little grains of sand,
Make the mighty ocean
And the beauteous land.”
—Julia A. Fletcher Carney (1823–1908)