November 1930
INDUSTRIAL A N D ENGINEERING CHEMISTRY
door weathering adequate for most normal applications, On the basis of accelerated tests a life of 20 years or more appears to be reasonable. ACKNOWLEDGMENT
The authors wish to expres8 their thanks and appreciation to B. 5. Biggs and F. 8.Malm of these laboratories; to H. G. Johnstone of the Western Electric Company for many helpful discussions during the course of this work; and to G. F. Brown and F. R. Criger who prepared and tested many of the compounds. Both the Bakelite Corporation and the Du Pont Company were of great assistance in supplying many of the special polymers used. LITERATURE CITED
(1)Am. Soc. Testing Materiels, Method D 926-47T. (2) Clarke, W.J., Elec. Eng., 64,919 (1945). (3)Crafton, H. C., and Slade, H. B., Modern Plastics,21,90 (1944).
2325
(4) DeCoste, J. B., Malm, F. S., and Wallder, V. T., presenbd before Division of Paint, Varnish, and Plastics Chemistry, 117th Meeting, AM. CHEM.SOC., Detroit, April 1950. (5) Fawcett, E. W., Gibson, R. O., Perrin, M. W., Paton, J. G.. and Williame, E.O., Brit. Patent 471,590 (Sept. 6, 1937). (6) Hahn, F. C., Macht, M. L., and Fletcher, D. A., IHD. ENG. CHEM.,37, 526 (1945). (7) Kreisher, C., Bell Labs. Record, 23, 321 (1945). (8) Maibauer, A. E., and Myers, C. S., Trans. Electrochem. Soc., 90, 449 (1946). (9) Myers, C. S., Modern Plastics, 21, 103 (1944). (10) Ollinger, C. G.,Paint,Oil,Chem. Rev., 103,9 (1941). (11) Shackleton,J. W., Elec. Eng., 64,912 (1945). (12) Smith, E. F., and Dienes, G. J., A.S.T.M. Bull., p. 46 (October 1948). (13) Swallow, J. C., Endeavour, 3, No. 9, 26 (1944). RECEIVED April 6, 1960. Presented before the Division of Paint, Varnish, and Plastics Chemistry at the 117th Meeting of the AMERICAN CHlcwcaL BocIerY, Detroit, Mioh.
Stability of Carotene in Alfalfa J
EFFECT OF FEED INGREDIENTS H. L. MITCHELL AND RALPH E. SILKER Kansas Agricultural Experiment Station, Manhattan, Kan.
A study was made of the stability of carotene in dehydrated alfalfa meal when the latter was mixed with other feed ingredients. Expeller soybean meal and cottonseed meal mixed in a 1:l ratio with alfalfa meal exerted an appreciable stabilizing influence on the carotene, whereas solvent meals were low in stabilizing activity. Carotene stability was improved as the percentage of expeller meals in the mixtures was increased. Cottonseed glands and rice bran also were effective in reducing carotene destruction. Hops and linseed meal were detrimental$ their presence caused carotene to be destroyed more rapidly than the carotene of undiluted alfalfa meal. A number of other materials had little effect on carotene retention.
E
VIDENCE has been presented ( f , S , 6, 7) to show that some ingredients of mixed feeds may affect the stability of carotene in the feed. Most of the'work has been done with carotene which was dissolved in oils and added to feeds in the form of carotene concentrates. Fraps and Kemmerer (3)added carotene to corn meal, yeast, skim milk powder, and wheat gray shorts in various combinations and found that the carotene was destroyed when the feeds were stored a t 28' C. Bickoff and Williams (I) used rice bran, oat flour, whole-wheat flour, and powdered potato as carotene carriers and found that the carriers varied in their ability to stabilize the carotene. Morgal, Byers, and Miller (7) stabilized carotene concentrates to some extent by mixing them with soybean meal. Mitchell, Schrenk, and King (6),studying various feed ingredients aa carriers for carotene concentrates prepared from alfalfa, found that carotene wm most stable when mixed with soybean and cottonseed meals and that starch and glucose when used aa carriers permitted rapid carotene deterioration. Little haa been done to determine the effect of various feed ingredients on carotene stability when the carotene is present in alfalfa meal. Brunius and Hellstrom ( 8 ) reported that soybean meal improved carotene stability when mixed and pelleted with alfalfa meal, but the addition of ground oat8 had no effect.
To study this problem further, a number of materials often found in mixed feeds were added to dehydrated alfalfa meal to determine what effect they would have on the rate of carotene destruction in the alfalfa. EXPERIMENTAL
Each ingredient to be studied was ground to pass through a %mesh screen and was mixed with dehydrated alfalfa meal in the proportion desired. The mixtures were placed in quart fruit jars and were stored in a darkened constant temperature room maintained a t 25" C. Undiluted alfalfa meal was included in the testa to serve as a control. Carotene waa determined a t monthly intervals by the method of Silker, Schrenk, and King (9). Figure 1 shows the effect of 15 mixturas of dehydrated alfalfa meal with glucose, ground sorghum grain, cottonseed meal, and soybean meal. Also shown is the effect of adding 20% blackstrap molasses to alfalfa meal. The addition of glucose and molasses did not affect carotene retention when compared with the undiluted meal. Retention was somewhat greater than in the undiluted meal when ground sorghum grain was added and appreciably greater in the presence of soybean and cottonseed meals, A more extensive group of diluents was tested as described above. The results which were obtained are presented in Table I. Again the materials were mixed in a 1:1 ratio with dehydrated alfalfa meal, except for fresh brewers' yeast; the yeast comprised 10% of the final mixture. Again soybean and cottonseed meals imparted the greatest protection to the carotene of the alfalfa; the cottonseed meal was the best. Distillers' dried solubles and ground Westland milo sorghum grain exerted moderate protection, especially after storage for 3 months. Glucose again had no effect on carotene stability. Linseed meal, spent hops, and unspent hops decreased carotene stability, epent hops causing the greatest instability. Why this w&s true is not known. Spent hops are a by-product of the brewing industry, and presumably during the extraction of the hops a material having some stabilizing ability waa removed. To the authors' knowledge, hops are not incorporated ordinarily
I N D U S T R I A L A N D E N G I N E E R I N G CHEMISTRY
2326
TABLEI. CAROTENESTABILITYIN 1:l MIXTURESOF DEHYDRATED ALFALFA MEAL A N D VARIOUS DILUENTS (Stored at 25" C.) c-Mon Carotene tha Destroyed in $torag-- % Material Added None Cottonseed meal Weetland milo grain Distillers' Spent ho sdried solubles Unspent iops Glucose Fresh brewers' yewt
1
2
3
4
6
8
18 8
33 17 27 29 59 42 29
52 26 39 41 73 56 48
64 35 52 49 79 69 63
76 50 66 63 88 79 78
80 55 69 68 90 84 82
4
19 26
36 41
50 55
67 66
74 70
16 11 20 21 25 10
28 20 40
48 31 60 65 51 40
58 39 74 71 66 52
73 56 85
76 62 89
10 14 48 21 17
(10%)
13
Dried brewers' yeast Dehydrated sorghum plants Soybean meal Linseed meal None Converted rice bran Unconverted rice bran
55 43 30
Vol. 42, No. I 1
was suspected that they were both expeller meals. To determine if the method of removing oil from the seeds has a Felation to the stabilizing ability of the resulting meals, solvent and expeller meals of each were studied. Since it was desirable to know also if less than 60% would stabilize the carotene as well as greater amounts, various proportions of the meals were mixed with alfalfa meal. The results are presented in Tables I1 and 111. In both cases, only the expeller meals were effective in reducing carotene destruction. Increasing the proportion of the expeller meals gave a corresponding increase in protection to the carotene.
TABLE11. STABILITY OF CAROTENE IN DEHYDRATED ALFALFA MEALWHENMIXEDIN VARYING PROPORTIONS WITH EXPELLER AND SOLVENT SOYBEAN MEALS (Stored at 25' C.) Peraentage Carotene Destroyed % ' of Months in Stors&-Mixture 1 2 3 5 6 7--
into feeds. They were used in these tests because it has been stated that hops contain an antioxidant. If this is true, the antioxidant was not effective in reducing carotene destruction under the conditions of these tests. Both fresh and dried brewers' yeast improved carotene retention slightly, and were similar in behavior after about 2 months of storage. During the first month, however, fresh yeast markedly inhibited carotene destruction. Because of the moisture in the fresh yeast, the moisture content of the mixture was 12%. This was high enough to permit fermentation, which has been shown to inhibit carotene destruction due to oxygen consumption during the fermentation reactions (4, 6 ) if the sample is in an airtight container. Or perhaps the greater carotene retention waa due to oxygen consumption by the fresh yeast itself early in the storage period. I
I
I
I
I
I
I
I
Material Added Alfalfa only Expeller meal
8
.I
14
32
39
59
68
76
5 10 20 30 50 70
18 13 17 15 10 10
28 33 27 25 26
42 44 40 43 38
58 56 56 53 45 38
70 68 68 62 52 45
78 75 72
21
30
88
56 54
In an effort to enhance the stabilizing ability of the cottonseed meal, 100 grams of the meal were moistened with 30 ml. of alcohol containing 0.2 gram of nordihydroguaiaretic acid (NDGA) anh 0.2 gram of citric acid. The alcohol was allowed to evaporate, and the meal waa mixed with 100 grams of alfalfa meal. Thus, the final mixture contained 0.1% NDGA and 0.1% citric acid. A 200-gram sample of alfalfa meal wm treated in the same manner and stored undiluted to serve m a control. The carotene stability of these samples, shown in Table I11 also, was no better than the corresponding samples which contained no added NDGA and citric acid. A sample of defatted cottonseed flour and a sample of cottonseed pigment glands (10)were obtained from the Southern Regional Research Laboratory, New Orleans, La., and were studied for stabili~ingability by mixing in a 1:1 ratio with dehydrated alfalfa meal, Table IV shows that no stability was imparted by the cottonseed flour. On the other hand, the glands did increase carotene stability to some extent,.
ALFALFA TABLE. 111. STABILITY O F CAROTENE IN DEHYDRATED MEALWHEN MIXEDIN VARYING PROPORTIONS WITH EXPELL~R AND
Figure 1. Effect on Carotene Stability of Mixing Dehydrated Alfalfa Meal with Various Feed Ingredients 1 = alfalfa only: 2 = oottonseed meal' 3 = ground sorghum grain: 4 P glucose: 5 = soybean meal: 6 = molwes.
In another experiment, the data of which are shown in Table I also, the effect of two typea of rice bran was determined. Unconverted rice bran is the bran obtained in the milling of raw rice. Converted rice bran is the bran from rice which has been given a special parboiling treatment prior to milling (8). These data show that both types exerted a stabilizing influence on carotene; the unconverted bran was much more effective, however. Saybean and cottonseed meals were chosen for further study because of their appreciable ability to stabilize carotene when mixed with alfalfa. Nothing was known of the proceasing history of the meals used in the preceding experiments, although it
Material Added Alfslfa only Expeller meal
+
Alfalfa NDGA and citrio acid Ex eller meal 46 D G A and citria acid
SOLVENT COTTONSEED MEAM
(Stored at 25' C.) Percentage Carotene Destroyed % of 7 Months in Stora&--Mixture 1 3 4 5 6
..
10
16 12 17 11 6 13
46 47 44 42 32 25 46
61 59 54 53 44 32 61
50 70
14 6
45 40
66 51
..
17
53
50
13
35
10 20 30 50 70
15
8
69 66 62 62 48 36 69
73 70 67 64 52 41 71
46 77
65
73
74
80
47
53
54
63
79 74 73 70
BO
November 1950
INDUSTRIAL AND ENGINEERING CHEMISTRY
2327
ACKNOWLEDGMENT
TABLE IV. STABILITYOF CAROTENE IN DEHYDRATED ALFALFA The authors are indebted to the following for supplying matMEAL WHENMXXEDWITH COTTONSEED'FLOUR AND COTTONSEEV terials used in this study: The W. J. Small Co., Inc., Kansas GLANDS City, Mo.; Hiram Walker and Sons, Inc., Peoria, 111.; Anheuser(Stored at 26O C.) Busch, Inc., St. Louis, Mo.;' Converted Rice, Inc., Houston, Peroentage Carotene Destroyed % of --Month8 in Storaie Tex.; American Rice Growers Cooperative Association, Houston, Material Added Mixture 1 3 4 6 6 8 Tex. ; Archer-Daniele-Midland Co., Minneapolis, Minn.; The Alfalfa only 11 46 62 70 74 81 Buckeye Cotton Oil Co., Cincinnati, Ohio; Wm. J. Stange Co., Cottonseed flour 10 11 37 66 66 67 77 Chicago, Ill.; Southbrn Regional Research Laboratory, New Orleans, La.
--.
..
Cottonseed glands
70
14
49
64
72
76
60
8
33
49
68
69
LITERATURE CITED
68
DISCUSSION
The reason for the ability of some materials to stabilize carotene when mixed with alfalfa ie not clear, since the carotene is within the alfalfa particles and presumably does not come in contact with the active materials in the diluents. One possible explanation is that substances in the added materials are easily oxidized and thus cause a depletion of oxygen surrounding the particles of the mixture. This seems unlikely, since each sample jar was rolled before removing a portion for analysis, and each jar waa opened monthly. This should have supplied oxygen to replace that which might have been used up. Furthermore, there was a considerable head space in the jars, which should have s u p plied enough oxygen for considerably more oxidation than occurred. Another possible explanation is that some exchange of substances could have occurred from the diluenta to the alfalfa meal by way of the small quantity of oil that wm present. Since carotene is in the oil phase of alfalfa, it then would be in contact with the stabilizer. Further work will be needed to determine why such mixtures are more stable and what practical use can be realized from the phenomenon.
(1)
Bickoff, E., and Williams, K. T., IND. ENG.CHEM.,36, 320
(2)
Brunius, E., and Hellstrom, V., Suensk. Kem. Tide, 57, 86
(1944). (1946). (3) Fraps, a. S., and Kemmerer, A. R., Tez. Am. Ezpt. Sta.Bull. 557 (1937). (4) Halverson, A. W., and Hart, E. B., 3. Dairy Sci., 30,245 (1947). ( 5 ) Mitchell, H. L., Schrenk, W.G.,and King, H. H., Arch. Biochem., 16,343 (1948).
(6) Mitchell. H. L., Schrenk, W. G., and King, H. H., IND.ENQ. CHEM.,41, 570 (1949). (7) Morgal, P. W., Byers, L. W., and Miller, E. J., Ihid., 35, 794 (1943).
(8) O'Donnell, W. W., Food I d . , 19, 763 (1947). (9)
Silker, R. E., Schrenk, W. G., and King, H. H., IND. ENO.
(10)
Vix, H. L. E., Spadsro, J. J., Westbrook, R. D., Crovetto, A. J., Pollard, E. F.,and Gastrook. E. A., 3. Am. Oil Chemists' SOC.,
CHlM.,
ANAL. ED., 16, 513 (1944).
24,228 (1947). RECEIVED April 10. 1960. Presented before the Division of Agricultural and Food Chemistry, 118th Meeting, AMERICANCREMICAL SOCIETY,Chicago, Ill. Contribution No. 408, Department of Chemistry, KEMW Agrioultural Experiment Station. This work waB supported by the K ~ M I U Industrial Development Commission.
Concentric-Tube Fractionating Columns CONARD K. DONNELL AND ROBERT M. KENNEDY Research Laboratory, Sun Oil Company, Norwood, Pa.
.
T h e concentric-tube fractionating column has been shown to be very useful for the precise fractionation of samples ranging from 10 to 50 ml. in volume. Details of constructing and testing such columns are given. The height of equivalent theoretical plate (H.E.T.P.) at total reflux of the columns ranged from 5.3 mm. at 30 ml. per hour boilup to 30 mm. at 300 ml. per hour. The two columns described had annular spaces 840 and 940 mm. long, giving separating powers in excess of 150 theoretical plates at low boiling rates. Pressure drop varied between 0.3 and 0.9 mm. of mercury and holdup between 0.01 and 0.05 ml. per theoretical plate. The width of the annulus in each column was 0.75 mm.
T
HE concentric-tube fractionating column was originated by Selker, Burk, and Lankelma (8) of the Standard Oil Company of Ohio for the precise fractionation of small samples of complex mixtures such as alkylates. These investigators constructed a still having three concentric annuli, each 1 mm. wide and 150 cm. long, which had a liquid holdup of 5 ml. and developed 85 theoretical plates at a boilup rate of 100 ml. per hour.
After conferences with M. d. Hartig and others of the Standard Oil Company of Ohio staff, the development work was continued in the authors' laboratory. Attention was concentrated on columns having only a single annulus, becauw the effort of properly distributing reflux to a number of annuli did not appear to be justified by the additional throughput that would have been obtained. The first successful columns were described in the Symposium on High Temperature Analytical Distillation conducted by the American Petroleum Institute (1) in November 1946. Since that time a number of major improvements have been made to facilitate the construction and operation of the columns. Good resulte have been achieved in the fractionation of alkylates with charges of 15 to 30 ml. and distillation times of 24 to 96 hours, depending on the siie and complexity of the sample. Fractions of 0.5-ml. volume are usually collected and then analyzed for their individual components by mesns of their infrared spectra. CONSTRUCTfON
The general design of the still is shown in Figure 1 and details of the upper and lower parts of the mlU& are shown in Figures 2 and 3.
