INDUSTRIAL A N D ENGINEERING CHEMISTRY
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Vel. 16. No. 9
Vitamin Potency of Cod-Liver Oils’ IX-Oil Produced by the Rotting Process By Arthur D. Holmes THEE. L. PATCRCo.. BOSTON,MASS.
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Three liver oils were prepared from the same lot of livers, one from livers from fish that had URING practically freshly rendered lirrers, the second from liocrs rotted 4 months, and the been out of the water only a the entire Christian third from livers rotted 8 months. The chemical and physical characfew hours. These livers era, fish-liver Oils Were cut into two Parts and have been used for mediciteristics of the three oils were determined and compared. The vitamin potency of the oils was studied under comparable experimental dividedinto two lots SO that rial Purposes. Until very conditions, and it was found that the vitamin potency of the oils deeach lot contained a lobe recently, these liver Oils creased as decomposition progressed. from each liver. One lot were manufactured by the so-called “sun-dried” or of livers was r e n d e r e d “rotting” process. I n brief, promptly under laboratory this process consists of allowing fish livers to decompose until conditions. The second lot was put in an earthen crock and the liver tissues have been weakened sufficiently to release the placed on the roof of a four-story building exposed to sunshine, liver oil. Owing to its lower specific gravity, the oil rapidly storms, and fluctuating temperature. rises to the top of the mass, where it is bailed off. When the livers had rotted 4 months, a sample of oil was This method of separating oil from the livers of cod, hake, removed for experiment purposes. After the livers had been haddock, .pollock, or other fish producing fat-rich livers exposed to the weather for another 4 months, a third sample of has certmn commercial advantages. It requires no atten- oil was obtained. The samples of freshly rendered oil, the oil tion and no equipment other than a barrel, which possibly from livers rotted 4 months and from livers rotted 8 months were analyzed by the usual laboratory methods. The reexplains its use even u p to the present time. The average fish-liver oil produced by the rotting process is sults are reported in the table. high in free fatty acids and contains fat-soluble decomposic ~ ~ E M I C A LAND PHYSICAL CHARACTERISTICS OB POLLOCK-LIVER OILS -ROTTEDtion products which possess undesirable odors and flavors. Fresh oil 4 months 8 months The quality of the best grade oil, the light brown oil, produced gravity 0.9210 0.9296 0.9548 Refractive index 1.4775 1.4787 1.4795 by the short-time rotting process, may be greatly improved by 186.4 206.8 Saponification 187, chemical treatment. Iodine value 151.4 142.3 112.9 Free fatty acid 1.3% 14.9% 23.3% The fatty acids can be removed, and the objectionable color, flavor, and odor materially decreased by decolorizing, deodorThe figures for specific gravity, refractive index, and izing, and alkali-washing s a p o n i f i c a t i o n value of the three oils under test processes. Considered from the standpoint of energy increased as the rotting value, renovated oils would process proceeded. The iodine number was matebe as valuable as oils renSTARTED LIVEI? OIL dered from fresh livers. rially lowered as decomposiSince a t the present time tion progressed. The effect of the rotting process was medicinal cod-liver oils are administered principally as particularly noticeable in the formation of free fatty a source of fat-soluble viacids, for the free fatty acid tamins, the question natucontent of the oils from rally arises as to whether livers rotted 4 and 8 months liver oils produced by the rotting process have a was 14.9 and 23.3 per cent, respectively, as compared potency equal to that of oils with 1.3 per cent for the produced from fresh livers. freshly rendered oil. It was for the purpose of securing information in this To secure information c o n c e r n i n g the vitamin connection that the experipotency of these oils, three ments discussed herein were comparable series of tests undertaken. were made with laboratory EXPERIMENTAL animals. All the animals were produced by the same T o provide freshly renb r e e d i n g colony. Their dered and rotted oils from a diet during the experimental common source the author period was identical with obtained a supply of pollock that described in earlier 1 Presented before the Division papers,2 and consisted of of Chemistry of Medicinal Prodpurified casein 18 per cent, ucts at the 67th Meeting of the A m eri c a n C h e m i c a1 Society, Washington, D. C., April 21 t o
26, 1924.
2 J . Metabolic Research, 2,131 (1922); 8, 685 (1923).
September, 1924
INDUSTRIAL A N D ENGINEERING CHEMISTRY
peanut oil 22 per cent, cornstarch 28 per cent, milk sugar 28 per cent, and salt mixture 4 per cent, supplemented by a 0.2gram tablet of dried brewer's yeast daily. When the physical condition of the experimental animals indicated that their body reserve of vitamin A had been exhausted, they were divided into three groups and their diet
rendered oil, it is found that approximately three times as much of the oil from the livers rotted 4 months were required to produce the same growth as witb freshly rendered oil. Of the seven animals fed the oil from livers rotted 8 months (Chart 37), not a single animal was able to compIete the 45-day experimental period, even though the amount of oil I
VITAMIN POTENCY OF LIVER OIL
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was Supplemented with varying amounts of the freshly renddred oil, oil from livers rotted 4 months, and oil from livers rotted 8 months. The accompanying charts supply detailed data concerning the change in body weight and the food intake of the experimental animals. I n the tests of the vitamin potency of the freshly rendered oil (Chart 35), seven animals were fed amounts of oil varying from 0.21 to 2.42 mg. daily. One rat (No. 241) was able to do slightly more than maintain his body weight on as little as 0.21 mg. of the oil daily. The remainder of the animals receiving from 0.42 to 2.42 mg. of oil daily grew rapidly. Six animals were used to determine the vitamin potency of the oils from livers rotted 4 months. Comparing the results of these tests (Chart 36) with those obtained with the freshly
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that they were fed in one instance exceeded 6 mg. daily. Comparing these results with those obtained with the freshly rendered oil, it is evident that this oil contained less than one-twelfth of the vitamin potency possessed by the freshly rendered oil. CONCLUSION From these results it is evident that fish-liver oils produced by the rotting process do not have as high vitamin A potency as oils produced from fresh livers. This conclusion is in accordance with the generally accepted belief of cod-liver oil manufacturers that the highest grade of cod-liver oil is obtained when strictly fresh livers are promptly rendered under carefully controlled rendering conditions.
Calendar of Meetings American Chemical Society-68th Meeting, Ithaca, N. Y., September 8 to 13, 1924. The Franklin Institute-centenary Celebration, Philadelphia, Pa., September 17 to 19, 1924. American Mining Congress-Sacrarnento, Calif., September 29 to October 4, 1924. American Electrochemical Society-Detroit, Mich., October 2 to 4, 1924. American Ceramic Society-Los Angeles, Calif., October 6 and 7, 1924.
American Institute of Chemical Engineers-Pittsburgh, Pa., December 3 to 6, 1924. Third Pan-American Scientific ~ ~ ~ Peru, ~Decem- ~ ber 20, 1924. American Association for the Advancement of Science-WashingtonJ D' December 29, to January 3J National Chemical Equipment Exposition and American Institute of Chemical Engineers-Providence, R. I., June 22 to 27, 1925.
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