Composition of Rye.
—From a study of many hundreds of analyses of rye of American origin the following table may be given as approximating the composition of a typical American rye:
| Weight of 100 kernels, | 2.50 | grams |
| Moisture, | 10.50 | percent |
| Ether extract, | 1.50 | „ |
| Protein, | 12.25 | „ |
| Fiber, | 2.10 | „ |
| Starch and sugar, | 71.75 | „ |
| Ash, | 1.90 | „ |
fig. 31.—Rye Starch. × 200.—(Courtesy of Bureau of Chemistry.)
The percentage of moisture in American grown rye is usually less than that of European origin. The American rye, also, has smaller kernels as a rule than that of foreign growth. In the content of protein the American samples of rye are fully equivalent to those of foreign origin, and in their mean composition, except as noted above, do not differ greatly from that of standard varieties collected abroad.
Protein of Rye.
—As is the case with other cereals more than one nitrogenous constituent exists in the rye. Three of the principal ones have been separated and named as follows: leucosin, gliadin, and edestin. Other proteins belonging to the globulin, albumin, and proteose family are also found in small proportions. The gliadin of rye resembles in its chemical and physical properties the gliadin of wheat. There is, however, in the rye no protein compound corresponding to the glutenin of wheat, and, therefore, rye flour does not form a gluten similar in quality to that of wheat, although it comes more nearly doing so than any other cereal. The gliadin of rye is soluble in alcohol, the leucosin of rye is soluble in water, and the edestin is soluble in a salt solution.
In a typical sample of American rye there will be found about 5.16 percent of gliadin, 2.27 percent of edestin and proteose, 0.55 percent of leucosin, and 3.14 percent of protein soluble in salt solution.