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prepared four extracts without alkali t o be used’ as standards for comparison. The menstruum used in all of the extracts was 50 per cent alcohol, for it was not for the purpose of reducing the amount of alcohol in t h e menstruum t h a t t h e experiment was made, b u t , on the contrary, it was a hope t h a t a faintly alkaline menstruum would more completely extract t h e bean and thereby increase both the physical constants and the flavoring powers of the extracts. The analytical results of this experiment appear in Table 111. The vanillin content was the same in all of these extracts. The alkali neither increased nor decreased it. This vould indicate again t h a t t h e vanillin of
/iNALYTICAL
RHSULTS OBTAIXED
M E X I C A N B E A N S AND
FROM
FIFTYP E R
\‘ANILLA
CENT
EXTRlCTS
M A D E FROM
ALCOHOLIC M E N S T R U A
CON-
T A I I I N C V A R Y I N G A M O U N T S OF P O T A S S I U M C A R B O N A T E
t h e beans is quite easily extracted, u p t o a certain limit, and t h a t what remains undissolved is held in t h e beans in such a way as t o make its extraction very difficult. The lead number values showed a rather marked increase with the increasing amounts of alkali. The standard extracts averaged in lead number ’ 0 . 5 6 5 and t h e samples containing the maximum amount of alkali averaged 0 . 9 9 7 , an increase of 0 . 4 3 2 or about 76 per cent. The interrening samples gave v,alues between these and were, with a few exceptions, greater the larger t h e amount of alkali employed. I n no case was the amount of alkali used sufficient t o render the finished extract alkaline. Extracts Xo. 9 contained the theoretical amount of potassium carbonate needed t o neutralize the acidity of t h e beans: calculated from t h e acidity of the standard extracts, b u t it was found t h a t these extracts were still acid and t h a t a n excess of t h e theoretical amount of alkali did not o\rercome the acidity of t h e beans b u t extracted more and more f r o m the beans. This is shonTn b y the increase of the lead numbers up t o t h e maximum amount used and t h e fact t h a t these extracts iyere still acid. The color of t h e extracts increased. u p t o a maximum, i\-ith the increasing amounts of alkali and would indicate t h a t this is also of a n acid nature, fa\-orably acted upon b y a small amount of alkali. The samples containing 0 . 28 per cent of potassium carbonate gave t h e maximum amount of color, which was 4 0 . 6 red and 1 0 2 . o yellom against 2 3 . I red and 7 6 . 2 yel-
1701. 8, S O .7
low in the standard samples. The clarity of t h e extracts was also greatly improved by the presence of the alkali and increased directly Jvith t h e increasing amounts of alkali used. Thus it is easily seen t h a t the lead number, t h e color values and the clarity of t h e extracts were increased in definite progression b y t h e use of t h e alkali. I t was found, however, t h a t t h e flavor of these extracts was not equal t o t h a t of t h e standards and seemed t o decrease with each additional amount of alkali. These extracts possessed a flavor t h a t is foreign t o B good extract of vanilla. The flavor might be described as being of greater “ b o d y ” b u t clearly lacking in the delicate aroma which is so characteriktic of a good and pure extract. The cause of this off flavor is not fully clear b u t it is doubtless due the action of the alkali on t h e resins, forming potassium salts having a peculiar taste and flaT-or. Vanillin itself is acid in nature a n d can be neutralized with an alkali b u t neutralized \Tanillin has a taste not much different from t h a t of unneutralized vanillin and far different from t h e taste of the extracts made with alkali. T h e addition of a n acid t o the extracts. made with t h e alkaline menstrua, overcame t h e disagreeable taste b u t also threw out of solution t h e extra material which the alkali had dissolved and left an extract about t h e same in color and taste as those made without alkali. I n view of t h e formation of foreign flavor, t h e use of a n alkali in t h e preparation of pure extract of vanilla is not favored. ( T o be cotacluded in o u r next issue) 666 M A r 6 STREET, N. Y .
E A S T ROCHESTER,
THE DETECTION OF NATURAL AND ARTIFlCIAL PIGMENTS IN OLEOMARGARINE AND BUTTER BS’ LEROYS.
P A L M E R AND W A L T E R
E . TIIRUN
Received April 4, 1916
INTRODUCTION
The natural yellow color of butter and of the bodyf a t of dairy cattle, t h e latter being characterized b y its intense color in t h e case of the Guernsey and Jersey breeds, is noiy known’ t o arise from t h e direct transfer of the yellow pigment, carotin, from the feed t o t h e milk and body-fat. During the season of t h e year when t h e food of t h e dairy cow is more or less devoid of carotin and the butter, in consequence, loscs its natural yellow color, t h e law permits t h e butter manufacturer t o add certain harmless pigments t o t h e butter in order t h a t t h e consumers’ demand for yellow butter throughout the year may be satisfied. LIost of the various brands of “ b u t t e r color” on t h e market for this purpose are solutions of annatto in some vegetable oil, usually cottonseed oil. Certain other pigments2 are also permitted for butter coloring, b u t they are not in common use a t the present time. T h e Xatural Yellow 1 Leroy S.Palmer and C. H. Eckles, “Carotin: Pigment of M i l k F a t , etc.,” .7. B i d . Chem., 16 (1914), 191-249; lIissouri Agr. Research, B L ~ ~10s and . 11 (1914). Among t h e permissible vegetable pigments are turmeric, saffron, marigold and safflower. T h e only yellow or orange coal-tar dyes allowed under the Federal Law are S a p h t h o l Yellow S and Orange I.
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The Federal Law also permits the use of t h e abovementioned pigments for coloring oleomargarine, b u t a t t h e same time imposes a n additional t a x of I O c. per lb. on t h e colored product. Oleomargarine mixed with highly colored butter t o give it a yellow color, or manufactured from beef fat with a high natural yellow color for t h e same purpose is also subject t o t h e color tax. Many states have statutes with clauses t o this effect. For example, t h e Missouri statutes declare t h a t , “ t o add t o or mix with oleomargarine any artificial coloration t h a t causes it t o look like butter of a n y shade of yellow,” renders the person so doing a n oleomargarine manufacturer in the eyes of t h e law. Although t h e Federal Law permits t h e . use of coloring matter in the manufacture of oleomargarine, more t h a n half t h e states of t h e Union have statutes which prohibit t h e sale of oleomargarine with a n y color whatever, either natural or added. It is not possible for t h e manufacturers of oleomargarine t o comply with t h e letter of this law because practically all beef f a t contains some natural yellow color, although it may not be possible t o see this color until t h e f a t is rendered and viewed in t h e clear, liquid condition. The pigment of t h e natural beef fat is carotin, as previously stated. I t s presence in the natural s t a t e in all beef fats makes it necessary for t h e court t o decide how much natural yellow color is permissible under t h e law. The points for the chemist t o determine in t h e case of suspected samples of oleomargarine are: ( I ) whether the oleomargarine has admixed with it sufficient butter t o give i t t h e color found, a n d ( 2 ) whether the color is natural t o t h e fat, or has been added. The material presented in this paper was t h e result of a n effort t o arrive a t a satisfactory answer t o t h e second of these questions in t h e case of several suspected samples of oleomargarine. EXPERIXENTAL
Satisfactory tests for most of t h e permissible dyes and vegetable pigments, including annatto, are given in all t h e text-books dealing with food analysis, a n d also in t h e official methods of t h e Association of Official Agricultural Chemists. Although a negative test for t h e usual artificial pigments employed in butter coloring would probably permit t h e conclusion t h a t t h e coloring matter present was natural t o t h e butter or oleomargarine, no simple, direct test for t h e natural pigment of animal fats is given. Leach,l however, gives two tests for t h e detection of t h e coloring matter of t h e carrot when added t o butter or oleomargarine; i. e., Cornelison’s2 a n d Moore’s3 tests. Inasmuch as the carotin of butter and beef f a t is now known t o be chemically and physiologically identical with t h e carotin of carrots, one of two conclusions seemed obvious: either ( I ) t h e natural carotin of butter and beef fat exists in a different state t h a n carotin added artificially t o these fats, Albert E. Leach, “Food Inspection and Analysis,” 3rd Ed., b y Andrew L. Winton, 1914, 536, 537. John Wiley & Sons, New York. 2 R. W. Cornelison, “A Method for Detecting Synthetic Color in Butter,’’ J . A m . Chem. SOL, 30 (1908). 1478. Russell W. Moore, “A Test for Carrot Color in Butter,” Analyst, 11 (1886), 163.
61j
or ( 2 ) the tests are not specific for added carotin, as t h e y are supposed t o be. C O R N E L I S O N ’ S TEST
Cornelison’s test consists of shaking I O g. of f a t with I O t o 20 g. of 9 9 . j per cent acetic acid and adding a few drops of concentrated nitric a n d sulfuric. acids, respectively, t o j cc. portions of t h e clear acid extract. According t o Leach, this test applied t o natural yellow butter gives a colorless extract, which remains colorless on adding nitric or sulfuric acids, while t h e acid extract from butter colored with carrot color is yellow, and remains yellow on addition of t h e nitric acid, b u t with sulfuric acid gives a pink color on standing. Reference t o Cornelison’s original article shows t h a t t h e statement in Leach does not agree with t h e results stated b y Cornelison in one very essential point, namely,” t h a t although Cornelison found t h e acid extract of natural butter t o be colorless and t o be unaffected b y nitric acid, when treated with sulfuric acid ,the same faint pink coloration resulted a s in the case of t h e extract of butter colored with carotin from carrots. Leach’s statement of Cornelison’s tests is further contradicted, and Cornelison’s results substantiated b y the following experiment: Ten cc. portions of natural yellow butter fat and colorless oleomargarine fat, colored with carotin from carrots,’ were shaken in separatory funnels with I O t o 20 g. of 9 9 . 5 per cent acetic acid. The acid layer was drawn off when it became perfectly clear on standing. It had a faint yellow color in each case, t h a t from the oleomargarine possibly being a little more intense t h a n t h a t from t h e butter, due undoubtedly t o the somewhat greater original color of t h e oleomargarine. The addition of 3 drops of concentrated nitric acid t o 5 cc. of each extract completely destroyed t h e yellow color. The addition of 3 drops of concentrated sulfuric acid t o j cc. of each extract produced a faint pink color, which, on standing for a few minutes, persisted for some time. MOORE’S
TEST
Attention was next directed t o Moore’s test. T h e conclusion t h a t would be drawn from the statement in Leach in regard t o this test is t h a t it was devised as a modification of Martin’s2 general test, making i t applicable as well for the detection of carotin. Leach states t h a t “Carotin (the coloring matter of t h e carrot root) does not impart its color t o t h e alcohol layer in Martin’s test.” “Moore has pointed out this exception, and shown t h a t with carotin present, t h e alcohol layer i n Martin’s test remains colorless as in t h e case of uncolored butter.” Reference t o the original papers b y Martin and Moore makes i t difficult t o understand how this conception of the relation between t h e two tests could have arisen. Mar1 This was done b y contact of t h e rendered, melted oleomargarine with dried carrot pulp for several hours, with frequent shaking. T h e f a t was filtered before using. Edward W. Martin, “Detection of Artificial Coloring M a t t e r in Butter Oleomargarine, Fats, Oils, etc.,” Analyst, 12 (1887), 70. Five grams of f a t are shaken with 25 cc. of a reagent made b y mixing 15 parts alcohol and 2 parts carbon disulfide. T h e alcohol layer which separates on standing contains a n y artificial coloring mattes present in t h e f a t ,
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tin’s test, which is given b y Leach, was in reality published a year later t h a n Lfoore’s test, and was, moreover, a modification, making Moore’s test applicable t o t h e detection of a number of coloring matters, such as annatto, turmeric, aniline yellow, naphthol yellow, etc., and also included carotin. Martin states this specifically, and, in addition, states t h a t “ t h e natural color of fats, oils, butter, etc., in no instance colored the alcohol.” However, reference t o Moore’s original paper shows t h a t his test was, in a certain sense, a modification of a n earlier test by Martin? for detecting annatto in oils and fats, in which the a n n a t t o is extracted from the f a t with dilute caustic alkali.2 Martin’s general test for artificial coloring matter has undoubtedly proved a useful one for t h e preliminary detection of the presence of artificial pigments.3 Martin’s test is not applicable, howeter, t o t h e detection of either natural or added carotin in fat. Leach is correct in his statement in regard t o this, b u t not in his statement t h a t the exception for added carotin was pointed out b y Moore. Moore’s test for added carotin in butter fat and other fats, as given in t h e original article, is t o dissolve I O g. of f a t in barely sufficient carbon disulfide, and t o add t o this 2 0 cc. of 90 per cent alcohol. A drop of dilute ferric chloride solution is now added a n d t h e t u b e containing t h e whole shaken. According t o Moore, in the case of lard colored artificially with carotin from carrots4 the addition of the ferric chloride caused the alcohol layer t o “absorb t h e color from the carbon disulfide layer until the tints of t h e two layers were reversed,” while “natural butter, without artificial coloring matter, will not be decolorized b y this treatment even after standing for several days.” Moore states t h a t he obtained the same results with beef fat, mutton f a t , olive oil, and lard, colored b y warming t h e m for several hours in contact with ground carrots, as he did in the case of t h e lard tested as noted above. No mention is made, however, of trying t h e test on butter f a t colored b y carotin .in this manner, the assumption being t h a t t h e action would be similar. T o anyone familiar with the properties of carotin, particularly its relative solubility in different solvents, the principle which is supposed t o be t h e basis of Moore’s test is a t once seen t o be open t o question. One of t h e well-established properties of carotin is its much greater solubility in carbon disulfide t h a n in alcohol. T h a t t h e mere addition of a drop of dilute ferric chloride solution should cause a reversion of this property would be questionable even if the c2rotin were merely dissolved in carbon disulfide; t h a t this should occur when the matter is further compli1 Edward XV. Martin, “Detection of Annatto in Butter, etc.,” Analyst, 10 (1885), 15.3. 2 This method is still in common use for extracting a n n a t t o from fats. 3 T h e use of ether, acetone, etc., in the place of ethyl or methyl alcohol io the reagent, as suggested by Martin in his original paper, would not be possible if a separation of the fat from the solvent is desired, because the reagent made with ether, acetone, or other f a t solvents would dissolve t h e fat or oil completely. 4 Prepared according t o Husemann’s method. August Husemaun. “Ueber Carotin und Hydrocarotin,” Liebig’s Ann., 117 (1861), 200.
Vol. 8, NO. 7
cated b y t h e incorporation of the carotin in fat would be even more questionable. Several preliminary trials of hloore’s test were made on butter f a t with a natural yellow color. The results differed from Moore’s in two respects: ( I ) t h e test was found t o be specific for t h e carotin of natural yellow b u t t e r ; ( 2 ) t h e phenomenon involved in the test was found t o be merely a complete decolorization of t h e pigment in t h e f a t , and not a transfer of t h e carotin from t h e f a t t o ’ the alcohol layer. R1though the alcohol layer had a yellowish tint. a t t h e conclusion of t h e tests, no carotin was found t o be present. An a t t e m p t t o recover carotin as unsaponifiable matter, after saponification of t h e fat which n-as in solution i n t h e alcohol, gave negat,ive results. T h e yellow color of t h e alcohol layer, which led Moore t o believe t h a t carotin had been extracted b y the alcohol and ferric chloride, is undoubtedly caused b y t h e ferric chloride itself. Moore, himself, stated t h a t the pigment in the alcohol layer in his test failed t o give a green coloration with ferric chloride,l which is one of the properties of carotin given by Husemann. Carotin is a n unsaturated hydrocarbon a n d loses its color on osidation. Dissolved in fat, however, it is very stable towards all t h e ordinary laboratory reagents, such as most metallic salts, alkalies, dilute acids, both mineral and organic, a n d glacial acetic acid. T h a t i t should be decolorized so readily in Moore’s test through t h e agency of t h e ferric chloride seemed worthy of more extended study. Numerous tests on samples of butter fat with a natural yellow color showed t h a t the decolorization of t h e carotin could be brought about much more readily if a better contact was secured between the carotin and t h e ferric chloride t h a n is given by Moore’s test. For example, I or 2 drops of I per cent aqueous ferric chloride solution added t o a solution of 5 cc. of fat. in 2 5 cc. of hot absolute alcohol caused a n almost instantaneous decolorization of the fat, which separated colorless when the alcohol cooled, or if sufficient water was added t o cause the separation t o take place. Especially striking, however, was t h e reaction which was found t o take place when a very small crystal of pure ferric chloride was added directly t o 5 cc. of h o t , melted fat. On shaking, t h e ferric chloride dissolved in t h e f a t , and t h e yellow color was rapidly replaced b y a beautiful green color. When t h e fat -vas sha.ken with I O cc. of methyl or 9; per cent ethyl alcohol t h e green color was extracted and the f a t was found t o have been completely decolorized. If more ferric chloride waS added t h a n necessary t o decolorize t h e fat, t h e green color did not appear; instead, t h e fat remained yellow, due t o t h e excess ferric chloride in solution. On extracting this with alcohol t h e fat was found t o have been decolorized, t h e ferric chloride going into t h e alcohol layer and t h e f a t separating colorless. T h e green coloration seen in the above test was 1 I t seems probable t h a t Moore’s test grew out o f his a t t e m p t t o test for carotin with ferric chloride, according t o its property (as stated b y Hiisemann) of giving a green coloration with this reagent when in alcoholic solution. Instead, he got a decolorization of the fat. Moore does not s t a t e t h e origin of the test in his original paper.
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T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERING CHEMISTRY
f o u n d t o be due t o t h e ferrous chloride formed from t h e ferric chloride b y t h e reducing action of t h e carot i n , t h e carotin, at t h e same time, being oxidized a n d decolorized. Ferrous chloride solutions are characterized b y their green color, as is well known. Husem a n n l first pointed o u t t h a t carotin has a n action on ferric chloride, when he recorded his observation t h a t “ Eisenchloride erteilt der weingeistigen Losung eiqe bei auff allendem Lichte grunlich erscheinende dunklere Farbung.” He obviously overlooked t h e decolorization of t h e carotin in t h e test, a n d also t h a t alcohol itself reduces ferric chloride, methyl alcohol solutions being especially characterized b y their green color. We have found t h a t t h e reduction of ferric chloride t o ferrous chloride b y carotin m a y be strikingly shown b y dropping a crystal of t h e ferric salt on a freshly prepared amorphous residue from t h e chloroform extract of carrot pulp. T h e ferric chloride turns a beautiful green; a n d t h e aqueous solution of t h e reduced iron salt gives a strong test for ferrous ions on addition of potassium ferricyanide, care being taken t h a t t h e ferric chloride used alone shows no precipitate of “ Turnbull’s blue ” on addition of t h e ferricyanide. The yellow carotin residue, t o which t h e ferric chloride is added, is seen t o be colorless when t h e ferrous chloride is washed off with water, in which carotin is insoluble. With Moore’s tests so greatly simplified, a n d t h e basis of t h e reaction established, attention was directed t o showing whether carotin added artificially t o f a t would act differently from t h e carotin natural t o fat. For this purpose b u t t e r f a t naturally nearly free from carotin a n d rendered f a t from white oleomargarine were colored b y warming t h e melted f a t with carrot pulp12 with frequent shaking. T h e yellow f a t s prepared in this way, together with freshly rendered Jersey-cow body-fat, which had a high n a t u r a l yellow color, were subjected t o Martin’s t e s t , t o Moore’s test as given b y Leach, a n d also t o t h e several modifications of this test mentioned above. Identical results were secured in each test with all t h e fats. Martin’s test failed t o extract t h e carotin. b u t t h e ferric chloride caused a decolorization in all t h e tests in which its use was involved. T h e green coloration of t h e f a t , when just sufficient ferric chloride was added directly t o t h e f a t t o cause t h e oxidation of t h e carotin, was just as striking in t h e cases of added carotin as in t h e cases of t h e f a t s naturally colored b y this coloring matter. The conclusion drawn from these results was t h a t it is not possible t o differentiate b y this method between t h e carotin natural t o b u t t e r f a t a n d beef tallow (oleomargarine) a n d carotin t h a t has been added artificially t o these fats. I t was found possible, however, to detect t h e presence of both carotin a n d other pigments, such as a n n a t t o , when present in t h e same fat. This is due t o t h e f a c t t h a t a n n a t t o a n d all other pigments not natural t o fat can be practically quantitatively extracted from f a t b y Martin’s method if t h e f a t is Loc czt.. p. 226 Some carrots were peeled, ground up, a n d boiled with water. T h e pulp was pressed, dried, ground up as finely as possible, and used for coloring the fat 1
2
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shaken with several successive portions of Martin’s reagent. Several tests of this character were made, a n d i t was found t h a t when t h e extract was no longer colored in Martin’s test a n y coloring matter t h a t remained in t h e f a t could be readily identified as carotin b y t h e modified Moore’s test. Annatto, which belongs t o t h e same class of vegetable pigments as carotin, was also found t o be decolorized b y ferric chloride. When dissolved in f a t , however, its oxidation was not found t o be as rapid as t h a t of carotin. T h e very fact t h a t i t does respond t o t h e same test, however, makes its extraction from t h e f a t b y Martin’s or some other reagent necessary before testing for t h e presence of carotin. A U T H O R ’ S TEST
T h e following method, summarizing what has been given above, is recommended for t h e detection of artificial a n d natural (carotin) pigments in b u t t e r f a t and oleomargarine. Shake I O cc. of rendered, melted fat with successive 2 5 cc. portions of Martin’s reagent (15 parts 9 j per cent alcohol a n d 2 parts carbon disulfide) until no more color is extracted. Test t h e extracted coloring matter for a n n a t t o or other pigments b y one or more of t h e approved methods. Drain off all of t h e alcohol ‘from t h e f a t , a n d test t h e pigment remaining in t h e f a t for carotin b y adding a small crystal of pure ferric chloride t o t h e hot, melted fat. After thorough shaking, extract with IO cc. of methyl or 95 per cent ethyl alcohol. If t h e pigment was carotin t h e f a t which separates will, when melted, be seen t o be completely decolorized. If just sufficient ferric chloride is added t o cause complete decolorization t h e ferrous chloride formed will impart a beautiful green color t o t h e fat. DISCUSSION
One of t h e most interesting results of this brief s t u d y is t h e impossibility of differentiating between t h e natural yellow coloring matter of butter f a t a n d beef tallow, a n d t h e same coloring matter added artificially t o these fats. The conclusion t h a t would naturally be drawn from this result is t h a t t h e carotin of butter f a t a n d beef f a t exists there in simple solution. The question of how this pigment exists in animal fats was not investigated in t h e studies of t h e general question of yellow anima! pigments recently published b y one of us.1 T h e assumption was t h a t a simple solution of t h e pigments existed in t h e fats. T h a t assumption seems t o be substantiated b y t h e tests made in t h e present study. Mention of t h e fact t h a t t h e carotin natural t o b u t t e r f a t a n d beef f a t has a small amount of xanthophyl associated with i t has been purposely avoided throughout t h e paper for fear of confusing t h e main problem. Although xanthophyl is abundant in all vegetable matter containing carotin, i t comprises such a small proportion of t h e total coloring matter of b u t t e r fat a n d beef f a t , even under t h e most favorable conditions, t h a t i t can be practically left out of consideration Moreover, xanthophyl appears t o be as completely decolorized b y ferric chloride as carotin. The 1
Leroy S. Palmer and C. 13. Eckles, loc c z l
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existence of xanthophyl t o a n appreciable extent in carrots and the ready solubility of xanthophyl in f a t makes it reasonably certain t h a t i-t was present in the f a t in t h e cases of artificial coloration with carotin. in which as complete oxidation of the pigments by t h e ferric chloride resulted as in the cases involving t h e natural pigment only. From the 1-iewpoint of the analyst it is unfortunate t h a t i t does not appear possible t o detect the presence of carotin added artificially t o butter f a t or oleomargarine. This conclusion may be a hasty one, however. Although it v d l probably never be possible t o difierentiate between natural and added carotin in fats, it may be possible, should the food laws ever require it: t o tell mThether carotin has becn added t o fat. While no a t t e m p t has been made t o u-ork out a n y tests in this connection it is suggested t h a t the possibilities of determining whether carotin has been added lie in t h e fact t h a t xanthophyl is naturally present in animal fats in very small proportion of t h e total pigment, while it is present in much greater proportion in all the vegetable matter containing carotin which might he used as a source of carotin for the artificial coloration of f a t ; furthermore. it would not be possible t o extract t h e carotin from these sources without, a t t h e same time, extracting the xanthophyl. Xccordingly! butter fat or oleomargarine containing added carotin would likewise contain a much greater proportion of xanthophyl t h a n is natural t o these fats. I t is doubtful if any simple test can be devised for determining the relative proportion of carotin and xanthophyl in fat. The solution of the problem would probably have t o involve a separation of the total pigment from the fat and a subsequent separation of the extracted pigment into its carotin and xanthophyl portions b y means of one of t h e relative solubility properties of these two classes of pigments. These properties are discussed fully in the studies on animal pigments previously published from this laboratory. As the question is not one of immediate moment t h e reader interested in t h e question is referred t o t h e publications mentioned. The strong reducing action of carotin on ferric chloride, which is the basis of the method for t h e detection of carotin, suggested t h a t other reducible ferric salts might be similarly affected and accordingly ‘serve equally well for the detection of carotin. This was found t o be the case. Ferric nitrate was found t o oxidize and decolorize carotin in butter fat but t h e test using this salt could not be simplified as in the case of ferric chloride, owing t o the insolubility of ferric nitrate in fat. I t was found necessary t o add some reagent which mould dissolre both t h e fat and t h e ferric nitrate, such as acetone. No green coloration accompanied the decolorization of t h e carotin in this test. b u t instead there was a suspension of a reddish brown iron oxide formed from t h e ferric nitrate. SUMMARY
I-It is pointed out t h a t t h e detection of carotin (the natural yellow pigment of animal fats) in oleo-
Yol. 8. No. 7
margarine is made necessary by t h e oleomargarine laws of many stares. 11-Cornelison’s test for carotin artificially added t o €at is shown t o be qu0te.d wrongly in Leach’s “ F o o d Inspection and Analysis.” 111-The relation between Martin’s test for artificial pigments in fats and Moore’s test for carotin added artificially t o f a t , as given in Leach’s “ F o o d Inspection and 9nalysis,” is shown t o be confused, and t h e true relation is pointed out. IV--It is shown t h a t bloore’s test for carotin in f a t or oleomargarine is not alone specific for carotin added artificially, b u t is equally specific for t h e carotin natural t o animal fats. T----It is shown t h a t the carotin is not dissolved out of the fat in Moore’s test, as stated b y Moore. b u t is merely decolorized b y t h e ferric chloride added. The reaction involved is shown t o be a reduction of t h e iron and t h e simultaneous oxidation of t h e carotin. VI-Modification and iniprovements in Moore’s tests are given. A method is also suggested for detecting both natural and artificial pigments (other t h a n carotin) in the same f a t . VII---The relation of Moore’s test t o t h e question of the natural state of carotin in fat, and t h e possibility of determining whether carotin has been added t o butter fat or oleomargarine are discussed. DAIRYCHEHISTRYLABORATORY USIVERSITY OF MISSOERI, COLUIIIBI.~
CULTIVATION AND CANNING OF MANGOES IN INDIA TARINI CHARAN
CII.4UDHERI’
Received May 3, 1916
The mango tree: Martgijera i i z d i c u , is a large evergreen and native of t h e south of Asia. I t grows in the Tropical Himalayas a t 1:ooo t o 3,000 ft. above sea leTTel, from Kumaun t o Bhutan, Bengal and Southern India. It has been known and cultivated all over India from very remote ages. I t is profusely connected with Sanskrit mythology and some religious rites of t h e Hindus and finds a place in t h e old Hindu tales and folklore. Mention is made of it by most of the foreign travelers in India. F. Jordanus notes t h e remarkable quality of the fruit about 1328 A . D . , and Baber, the founder of the l l o g h u l Empire in India, speaks of the excellence of t h e mango. Later on, Gracia de Orta, in the year 1563, states t h a t t h e fruit is so delightfully tasteful and highly refreshing t h a t : when in season,2 no other f r u i t can sell. There are numerous varieties3 of mangoes in India, the best and most widely grown being Fazlee, Langrah and Bombay. T h e plants can be grown from t h e seed or stone of t h e fruit; b u t it, is found t h a t on t h e same soil t h e seedlings rarely produce fruit equal in size, taste and flavor Government Research Scholar in Chemistry. T h e general flowering period of mango trees is from December t o February, and t h e principal ripening season for mangoes is from M a y t o the middle of August. W a t t , D. E. P., Vol. 5, 147. 3 Woodrow, “ T h e Mango, Cultivation and Varieties,” 11, 191 I : Firminger, Mango-Gard. I n d . , 1904, 256-61. 1
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