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INDUSTRIAL AND ENGINEERING CHEMISTRY
lar formula. Table I1 shows the extent of these savings, which on the basis of current market prices amount to about 7.4 cents per load. As pointed out, a choice between savings and work quality must be made here, if such savings are to be realized. With the high metaphosphate formula sufficient supplies were saved to reduce the cost per load by 4.7 cents over and above the cost of the metaphosphate without any deleterious effects on work quality.
Acknowledgment Acknowledgment is made of the cooperation of John A.
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Fullerton who made the facilities of the United Laundries of Pittsburgh available for this study.
Literature Cited (1) Am. SOC.Testing Materials, Standards, Part 11, Non-Metallic Materials, pp. 1224-8 (1933). (2) Gilmore, B. H., Starchroom Laundry J.,40, 24 (1933). 31, 51-7 (1939). (3) H a t c h , G. B., and Rice, Owen, IND. ENQ.CHEM., (4) Morgan, 0. M., Can. J . Research, 6, 292-305 (1932). (5) Seiden, R., IND. ENQ.CHEM.,News Ed., 15 496-7 (1937). PRESENTED before the Division of Industrial and Engineering Chemistry a t the 99th Meeting of the American Chemical society, Cincinnati, Ohio.
Vitamin Content of Distillers’ C. S. BORUFF AND A. F. LANGLYKKE Hiram Walker & Sons, Inc., Peoria, Ill.
By-Products d
SIMON BLACK University of Wisconsin, Madison, Wis.
In this process for the complete recovery of distillers’ residues, a feed product is prepared which is composed of the insoluble portion removed on screens, a second insoluble fraction removed by centrifuges, and a sirup or soluble fraction recovered by evaporating the effluent thin slops. The composite distillers’ grains and the fractions of which it is composed were commercially dried and assayed by chick methods. The composite feed contains only small amounts of vitamins A and D, but 13.3 to 15 micrograms of riboflavin and 1.0 to 1.3 I. U. of vitamin B1 per gram, as well as sufficient chick antidermatitis factor to protect chicks at a feeding level of 30 to 40 per cent. The dried centrifuge sludge which is composed mainly of yeast solids, as well as the dried screenings, is relatively poor in water-soluble vitamins. The dried sirup contains 26 to 40 micrograms of flavin per gram, 2.0 to 3.0 I. U . of vitamin B1 per gram, and chick antidermatitis factor sufficient to protect at feeding levels of 10 to 20 per cent. This product is also a good source of factor W.
D
R I E D distillers’ grains have long been considered with favor as an ingredient in dairy feeds (11). This is particularly true of Corn Distillers’ Dried Grainsi. e., the product recovered from distillations in which corn is the predominant grain mashed. The type and quantity of protein, fat, and, probably to some extent, the vitamin content of these grains have played their parts in making these grains a favored constituent in dairy feeds. Quantitative
data on the vitamin content of these grains have only recently become available in the publication of D’Ercole et al. (7). The old type distillers’ grains, as described by Morrison ( I I ) , were composed only of the suspended grain solids that could be recovered by screening the spent mash (stillage) discharged from the stills. The finely suspended solids and solubles were run to waste or fed in the liquid form to hogs and cattle. This old type of distillers’ grains, which is a t present recognized in the trade as Light Distillers’ Grains, is referred to in this manuscript as Dried Screenings. The large and modern distillery now recovers the fine suspended solids and solubles that pass the screens, concentrates this material in multiple-effect evaporators, mixes the sirup so produced with the wet screenings, and then dries the combined materials in rotary dryers. This newer type of distillers dried grains is referred to commercially as Dark Distillers’ Grains or Distillers’ Dried Grains Containing Solubles. If all of the solubles are recovered and dried with the screenings, the final product will be composed of about equal quantities of each by weight on a dry basis. A variation in the standard method of complete recovery of distillers’ stillage as developed and patented by Hiram Walker & Sons, Inc., and described by Boruff and Miller (4) and Cooley (6), permits the removal of suspended grain fines, coagulated proteins, dead yeast cells, etc., from the screened stillage by the use of centrifuges. The centrifuge cake when dried is referred to as Dried centrifuge Sludge. The use of this process also permits the production of a sirup in the multiple-effect evaporators which is free of coarse material and concentrated in water-soluble grain fractions, as well as the watersoluble vitamins derived from the yeast and grain used in the fermentation process. This sirup can be dried on drum dryers to give what is referred to in this manuscript as Dried Distillers’ Solubles We also have available a solvent extraction plant through which may be passed part of the distillers’ by-products for removal and separate sale of the corn oil found in these grains (6). The Oil-Extracted Corn Distillers’ Dried Grains Containing Solubles have the same water-soluble nutrients as did the original dried grains from which they were produced. The protein level is enhanced by such treatment. For some time the research department of Hiram Walker & Sons, Inc., has considered the possibility of the use of distillers’ by-products in feeds other than dairy feeds, espe-
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cially the advantageous use of some of them in poultry rations. T o this end, arrangements were made with the Nutrition Laboratory of Massachusetts State College for preliminary vitamin assays of the various distillers’ by-products. These studies, reported by D’Ercole, Esselen, and Fellers (77, justified the continuance of the investigations. The present manuscript reports representative chemical analyses of different distillers’ by-products (Table I), as well as biological vitamin assay data on these same products (Table 11). Subsequent to the beginning of these biological assays, arrangements were made for large-scale poultry feeding experiments, the results of which are encouraging. These studies cover the use of Corn Distillers’ Dried Grains Containing Solubles, OilExtracted Corn Distillers’ Dried Grains Containing Solubles, and Dried Distillers’ Solubles in poultry rations.
Chemical Analyses Representative chemical analyses of the various distillers’ by-products as determined by standard procedures (2) are given in Table I. These data show the protein content of the Dried Screenings and the Dried Distillers’ Solubles, and hence the Corn Distillers’ Dried Grains Containing Solubles, all t o be about the same-27 to 29 per cent. Any variation in protein will depend on the percentage of corn and other grains used, the analysis of these grains, and the efficiency of the alcoholic fermentation. The data presented here deal only with corn distillers’ by-products or those in which corn represents the main cereal of the mash. The product derived from mashes in which rye predominates, or Rye Distillers’ Dried Grains, differs considerably in chemical analysis as shown by Morrison (f 1 ) and probably differs also in vitamin content. Dried Screenings average higher in fat than the Dried Distillers’ Solubles or the Corn Distillers’ Dried Grains Containing Solubles. The fiber content of the Dried Distillers’ Solubles (provided centrifuges or filters are used) is less than 1.0 per cent, whereas that in Dried Screenings runs about 12 per cent, All samples are low in ash and therefore the Dried Distillers’ Solubles and the Corn Distillers’ Dried Grains Containing Solubles can be fed to as much as 7 and 18 per cent of the diet, respectively, before any laxative effect is noted. These percentages are in excess of what need be added to supply the necessary vitamin G in a normal ration.
VOL. 32, NO. 9
Biological Assays The chick was used as the experimental animal in the biological assays reported in this paper. All groups contained five animals, and a positive and negative group were included in every assay. Vitamin A was determined by the method of Elvehjem and Neu (8). The samples to be tested were added t o the basal ration a t different levels, and the response obtained was compared with that secured with a standard preparation of carotene. Vitamin BI was determined by the method of Arnold and Elvehjem (1) which involves the determination of the minimum level of the sample necessary in the basal ration to give good growth and complete protection against polyneuritis in all the chicks in a group. Crystalline thiamin was used as the standard. The official method of the A. 0. A. C. (12’) was used for the determination of vitamin D. The percentage of ash in the tibiae from chicks grown on the basal ration plus different levels of the test material was compared with that obtained when standard amounts of vitamin D were fed. The riboflavin assays were made by the method of Bethke, Record, and Wilder ( 3 ) . The growth of the chicks on the basal ration plus the different levels of the sample was compared with that obtained when 200 and 300 micrograms of riboflavin, respectively, were added to the basal ration. The chick antidermatitis factor potency was determined by the method described by Mickelsen, Waisman, and Elvehjem (IO). Since no unit has been generally accepted for this factor, the relative potency of the different samples is expressed as the minimum percentage of the sample necessary in the basal ration to prevent the appearance of the deficiency symptoms. Three individual samples of Dried Distillers’ Solubles and a sample of the undried product (Distillers’ Solubles, Semi-Solid) were also assayed for factor W potency by comparison with standard preparations of pork liver and pork kidney, using the method of Frost and Elvehjem (9). The growth responses obtained showed both of these products to be good sources of this factor although not so potent as dried liver or yeast. There was no destruction of factor W in the drying process. The results of all assays are given in Table 11. It is obvious that both Dried Screenings and Dried Centrifuge Sludge are relatively low in the water-soluble vitamins. This is probably due to the fact that in the processes of distillation the yeast cells are broken u p and extracted by the aqueous phase, and therefore the vitamins are found in the concentrated thin stillage or solubles rather than in the insoluble constituents. The Dried Distillers’ Solubles carry a much larger amount of vitamin B1,riboflavin, and the chick antidermatitis factor. This product may be considered a relatively rich source of riboflavin, for the commercially produced
PERCENTAGE CHEMICAL ANALYSES O F DISTILLERS’ BY-PRODUCTS” TABLE I. REPRESENTATIVE No. 1 2
3 4 6
6
7
a b c
Protein Fat ( N X 6.25) (Ether Ext.) 29 11 Dried Screenings Corn 42 9 Dried Centrifuge( Sludge Corn 27 7 Dried Distillers’ Soluble: Corn 12 3 Distillers’ Solubles Corn’(Semi-So1id)b 28 9 Corn Distillers’ Dhed Grains Containing Solubles (Dark Grains) 28 9 Corn Distillers’ Dried Grains Containing Solubles (Air-DriedIC 31 1 Oil-Extracted (Hexane) Corn Distillers’ Dried Grains Containing Solubles All data except for N o . 4 adjusted to 8.0% moisture content. In practice, moisture may vary from 7 to 12%. Contains minimum 40% solids, maximum 80% moist,ure. Air-dried a t 49O C. (120O F.) for 48 hours instead of in commercial rotary dryer a t 82’ C. (180’ F.)for 35 minutes. By-product
Fiber 12 7 0.8 0.4 7 7 8
Ash 2 3 8 3.5 5 5 5
Acid Calcd. asLactic 0.2 0.2 9 4 5 5
5
TABLE11. VITAMINCONTENTOF DISTILLERS’BY-PRODUCTS No.
By-product
Dried Screenings Corn Dried Centrifuge( Sludge Corn Dried Distillers’ Soluble; Corn Distillers’ Solubles,, Corn’(Serni-Solid) Corn Distillers’ Dried Gra!ns Contaping Solubles Corn Distillers’ Dried Grains Contalnlng Solubles (Air-Dried) Oil-Extracted (Hexane) Corn Distillers’ Dried Grains Containing Solubles 0 Minimum protective level. b Value depends on a number of manufacturing variables. Estimated from value for Dried Solubles.
A
Bi Riboflavin --I. U.per gramMicrogramslpram 40 >40 10-20 25-45C 30-40 30-40 >40
....
....
Potent Potent
.... ....
....
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Summary The methods of preparation, chemical composition, and vitamin content of certain distillers’ feed by-products have been discussed. The Dried Distillers’ Solubles are most potent in the vitamins of the water-soluble B complex and are particularly valuable as a source of riboflavin, which is present in amounts of 26 to 40 micrograms per gram. This product is also a good source of factor W, though less potent than dried liver or yeast. Proper drum drying of these solubles does not affect the vitamin G, filtrate factor, or factor W potency. Dried Screenings, which correspond to the classical DRUMDRYERUSEDIS PREPARING DRIEDDISTILLERS’ SOLWBLES type of light-colored distillers’ dried grains containing no solubles are Dried Distillers’ Solubles examined contained between 30 low in vitamin content. Corn Distillers’ Dried Grains and 40 micrograms of riboflavin per gram. Subsequent Containing Solubles (screenings plus solubles) is a valuable biological assays of three other samples of this product showed source of the water-soluble vitamins, in particular, riboflavin. The content of fat-soluble vitamins-i. e., vitamins A and Driboflavin contents varying from 26 to 30 micrograms per gram. is relatively low although the product does contribute a certain amount of vitamin A (1.5 to 3.0 I. U. per gram). The addition of solubles to Dried Screenings gives the prodExtraction of oil from distillers’ grains reduces the content uct Corn Distillers’ Dried Grains Containing Solubles, which of vitamin A and of the chick antidermatitis factor, but does is valuable as a source of the water-soluble vitamins. The not affect the content of riboflavin and vitamin B1. old style light-colored distillers’ grains (Dried Screenings) is These findings suggested new uses for distillers’ by-prodlow in vitamin potency, as Table I1 shows. ucts. I n the past they have been used mainly in the comThe vitamin content of the air-dried Corn Distillers’ pounding of dairy feeds. The high content of flavin, the presDried Grains Containing Solubles is similar to the regular ence of other water-soluble vitamins from yeast, and the product. The vitamin A content may be slightly higher available food material present are leading to application of but not significantly so. These data indicate that the loss these products in the feeding of poultry where these factors in vitamin potency is insignificant during commercial dryare of such great importance. ing. The vitamin D content of all products assayed is very low. The extraction of oil from the distillers’ grains Acknowledgment by the use of hexane reduces the vitamin A content and The authors gratefully acknowledge the advice, consultalikewise removes a small amount of the chick antidermatitis tion, and direction given this problem by C. A. Elvehjem of factor. the University of Wisconsin where these studies were made. Riboflavin data on Corn Distillers’ Dried Grains Containing Solubles (13 to 15 micrograms per gram) and on the Dried Literature Cited Distillers’ Solubles (26 to 40 micrograms) check in order of (1) Arnold, Aaron, and Elvehjem, C. A,, J. Nutrition, 15, 403 magnitude with the earlier data on grains (14 micrograms) (1938). and on solubles (27 micrograms, calculated to the same mois(2) Assoc. Official Agr. Chem., Official and Tentative Methods of Analysis, 4th ed. (1935). ture basis) reported by D’Ercole, Esselen, and Fellers (7). (3) Bethke, R. M., Record, P. R., and Wilder, 0. H. M., Poultrw Routine commercial samples of Dried Distillers’ Solubles, Sci., 16, 175 (1937). now being produced by our plant, show a riboflavin content of (4) Boruff, C. S.,and Miller, D . L., W u n i c . Sanit., 9, 259 (1938). 25 to 32 gamma as measured by an adapted Snell and Strong (5) Boruff, C . S.,a n d Miller, D. L., Oil & S o a p , 14, 312 (1937). ( I S ) assay method. Physicochemical methods of analyses for (6) Cooley, L. C., IND. E X G .CHEM., 30, 615 (1938). (7) D’Ercole, .4.D . , Esselen, W.B., Jr., a n d Fellers. C. R., Poultru riboflavin have also been tried with variable results which Sei., 18, 89 (1939). do not check as closely with biological (feeding) assays as do ( 8 ) Elvehjem. C . A., a n d Neu. V. F.. J . B i d . Chem., 97. 71 (1932). . the results obtained by the adapted bacteriological method (9) Frost, D. V., a n d Elvehjem, C. A , , Ibid.,121, 255 (1937); (10) Mickelsen, O., Waisman, H. A., and Elvehjem. C . A., Ibid., of Snell and Strong. 124, 313 (1938). The Dried Distillers’ Solubles are being sold for use as a (11) Morrison, F. B., “Feeds and Feeding”, 20th ed., pp. 399-400, constituent in poultry feeds to replace, a t a saving, part of the 453, 533-4, Ithaca, Morrison Pub. Co., 1937. dried milk products used. The evaporated and concentrated (12) Sale, J. W.,J. Oficial Agr. Chem., 20, 72 (1937). Anal. Ed., 11, 346 (1939). (13) Snell a n d Strong, IND.ENQ.CHEM., solubles in the semisolid form (by-product 4 in the tables) is also finding application as a supplementary feed for poultry. PRESENTED before the Division of Biological Chemistry a t the 99th Meeting Both products are giving satisfactory results. of the American Chemical Society, Cincinnati, Ohio.
