The germ of a cereal grain is the part that develops into a plant;[1] it is the seed embryo.[2] Along with bran, germ is often a by-product of the milling[3] that produces refined grain products. Cereal grains and their components, such as wheat germ oil,[4] rice bran oil, and maize bran,[5] may be used as a source from which vegetable oil is extracted, or used directly as a food ingredient. The germ is retained as an integral part of whole-grain foods.[6] Non-whole grain methods of milling are intended to isolate the endosperm, which is ground into flour, with removal of both the husk (bran) and the germ. Removal of bran produces a flour with a white rather than a brown color and eliminates fiber. The germ is rich in polyunsaturated fats (which have a tendency to oxidize and become rancid on storage) and so germ removal improves the storage qualities of flour.[7]
Wheat germ
| Nutritional value per 100 g (3.5 oz) | |
|---|---|
| Energy | 1,598 kJ (382 kcal) |
51.8 g | |
| Sugars | 7.8 g |
| Dietary fiber | 15.1 g |
10.7 g | |
| Saturated | 1.83 g |
| Monounsaturated | 1.5 g |
| Polyunsaturated | 6.62 g |
29.1 g | |
| Vitamins | Quantity %DV† |
| Thiamine (B1) | 139% 1.67 mg |
| Riboflavin (B2) | 63% 0.82 mg |
| Niacin (B3) | 35% 5.59 mg |
| Pantothenic acid (B5) | 28% 1.387 mg |
| Vitamin B6 | 58% 0.978 mg |
| Folate (B9) | 88% 352 μg |
| Vitamin C | 7% 6 mg |
| Vitamin E | 107% 15.99 mg |
| Minerals | Quantity %DV† |
| Calcium | 3% 45 mg |
| Iron | 51% 9.09 mg |
| Magnesium | 76% 320 mg |
| Manganese | 868% 19.956 mg |
| Phosphorus | 92% 1146 mg |
| Potassium | 32% 947 mg |
| Zinc | 152% 16.67 mg |
| †Percentages estimated using US recommendations for adults,[8] except for potassium, which is estimated based on expert recommendation from the National Academies.[9] | |
Wheat germ or wheatgerm is a concentrated source of several essential nutrients, including vitamin E, folate (folic acid), phosphorus, thiamin, zinc, and magnesium, as well as essential fatty acids and fatty alcohols.[10][11] It is a good source of fiber.[12] White bread is made using flour that has had the germ and bran removed.[13]Wheat germ can be added to protein shakes, casseroles, muffins, pancakes, cereals, yogurt, smoothies, cookies, and other goods.[14]Wheat germ can become rancid if not properly stored in a refrigerator or freezer[15] and away from sunlight.[16]Some manufacturers prevent rancidity by storing wheat germ in vacuum-sealed glass containers, or by placing an oxygen-absorbing sachet inside air-tight packaging.
Other uses
In molecular biology, wheat germ extract is used to carry out cell-free in vitro translation experiments since the plant embryo contains all the macromolecular components necessary for translating mRNA into proteins but relatively low levels of its own mRNA.[17][18]
Wheat germ is also useful in biochemistry since it contains lectins that bind strongly to certain glycoproteins; therefore, it can be used to isolate such proteins.