I
NUTRIENT CONTENT OF
Alcohol Fermentation By-products FROM CORN J. C. BAUERNFEIND, J. C. GAREY, W. BAUMGARTEN, L. STONE,AND C. S. BORUFF
data. Some variation in analyses of these products does occur and is influenced by the percentage of corn in the mash bill, the analyses of the cereal grains themselves, the efficiency of the fermentation, the cooking temperature of the grain, the amount of backslop employed, and the type of equipment used in the dryer plant. The production of distillers' by-products has increased considerably since the autumn of 1941 due t o the fermentation of more grain t o high-proof ethyl alcohol for war use. The annual production of these by-products for 1938 through 1943 is presented in Figure 1. The 1943 production figures are, of courEe, estimates. The data on distillers' dried grains are U. 8. Department of Agriculture figures (16)and include all types of distillers, grains; the figures on distillers' dried solubles are the total production of the four companies making the product.
RAIN alcohol fermentation by-products, more commonly
G
known as distillers' by-products, possess high nutritive value. The purpose of this report is t o present new data on their nutrient con%nt so that the supplies of these products in this country may be fully and most economically utilined. Corn distillers' by-products have been defined by the Association of American Feed Control Officials (8) as the residues obtained in the manufacture of alcohol and distilled liquors from corn, or from a grain mixture in which corn predominates, after the removal of the alcohol. Only corn distillers' by-products will be discussed in this paper. I n the process of making alcohol or distilled liquors, the grain mixture is cooked with water and malted to convert the starch to fermentable sugars. Yeast is added to ferment the sugar t o alcohol which is removed by dis-
TABLEI. CHBMICAL COMPOSITION OF CORNDISTIL~RS' BY-PRODUCTS (IN h
Protein
Fat
Hiram Walker & Sons, Inc., Peoria, Ill.
DISTILLERS' SOLUBLE S
Corn distillers' dried solubles is a grain-yeast concentrate comprising the water-soluble nutrients- derived from the original grains and from the grain-yeast fermentation. It also containa some grain fines and the majority of the yeast cells which have remained in suspension. The yeast cell (all dead) content of the dried product can be estimated either by hemacytometer counts of the thin stillage, of the semisolid solubles, or of the dried solubles; with a resulting figure of 4 billion cells, plus or minus half a billion, per gram. When this figure is compared to that of dried yeast made from the same strain of Saccharomyces cerevisiae, the approximation is reached that 20 per cent by weight of the dried solubles is dried yeast. Although all the product now commercially made is drum-dried and flaked, i t can be spray-dried.
R CBNT)
Lactic Acid Calad. from Detd. by acidity oxidation0
(eT\i$ (E.% Fiber Ash By-product Dried solublesb 27 7 1 8 9 7.6 Dried graiins 80 10 12 2 0.5 0.6 Dried grains with ao1.o 29 9 7 4 4 8.6 a Aqueous hydrolyzed extract ie oxidized by method of Friedmann and Graeser (e). b Moisture content, 6.0%. 0 Moisture content, 10.0%.
tillation. The stillage, containing 4.8-6.0 per cent total solids (depending on beer gallonage per bushel) is discharged onto screens, on which are retained the coarse grains. These screenings are dried in rotary steam tub dryers and are known as corn distillers' dried TABLHI 11. VITAMINAND CAROTEINOID CONTENTOF CORNDISTILLERS' grains. I n the total recovery of stillage, the @*-P&ODUCTS thin stillage passing the screens is concentrated Vitamin or Dried Dried Grains Dried Carotenoid Type of Away Soluble8 with Soh. Graina in evaporators t o a heavy sirup (semisolid corn -Micrograms per gramdistillers' solubles) and is mixed with the screenThiamine 8-9 8-4 1.5 gyi;uJ ings for drying. The resulting product is 7-10 3-4 1-2 Riboflavin Chick ( 4 14) 25-30 13-16
