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though it may have been due to the effect of natural acidity of the juice. It is highly advantageous from the standpoint of sirup production, because the presence of invert sugar retards, and when present in sufficient quantity, prevents crystallization of sucrose. For purposes of sirup production, it would seem to be desirable t o select or breed varieties of sorghum, the juice
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from which contains minimum quantities of starch a t maturity. However, the ease of filtration of the juice, the elimination of jellying of the sirup resulting from treatment with malt diastase, and the elimination of scum-forming constituents by filtration, indicate that the process may be applied with great advantage to the commercial production of sorghum sirup.
Suitability of Various Solvents for Extracting Vanilla Beans' Part
I
By J. B. Wilson and J. W. Sale WATER
W
ITH the advent Of prohibition and "le
AND
BEVERAGE LABORATORY, BUREAUOF CHEMISTRY, WASHINGTON, D.
Because of the restrictions on the use of alcohol which have followed prohibition, and the consequent substitution of other solvents for extraction of flavors, some preliminary work has been done to determine whether or not these alcohol substitutes produce the same amount and kind of extracts as those prepared f r o m ethyl alcohol. This investigation was limited to several varieties of vanilla and the tonka beans, and the solvents selected were isopropyl alcohol, ether, acetone, and carbon tetrachloride, to be compared with ethyl alcohol.
c. 500-cc. flasks and covered with 200 cc. of solvent. The solvents used were " and 95 per cent isopropyl ether, acetone, and
placing Of restrictions On the purchase and use Of interIn est has been manifested in One series Of 'perations the the Of Other than for The results show that the alcoholic solvents are much superior f r o m beans mTere with the standpoint of quantity of extraction, the carbon tetrachloride grams Of potassium carbonthe manufacture Of ins and flaVors) and ate and then extracted with in being the poorest i n this respect. I t is possible, however, that a 65 per cent ethyl alcohol. the reduction Of the Wanpreliminary extraction with ether or carbon tetrachloride followed tity Of which by a weak alcoholic solution m a y be found practicable. Work on The characters of vanilla extracts made is used' The United States the analysis of the final extracts i s still i n progress. Department of Agriculture, with 65 and 95 per cent ethyl alcohol and with alkain Circular 136, defines a flavoring extract as "a solution in ethyl alcohol of proper line 65 per cent ethyl alcohol are quite well known, so that strength of the sapid and odorous principles derived from these solvents were used as standards with which to compare an aromatic plant, or parts of the plant, with or without the characters of the extractive matters obtained with the its coloring matter, and conforms in name to the plant used other solvents. Isopropyl alcohol, ether, acetone, and carbon in its preparation." It is further held, under the Federal tetrachloride were selected, because they are available in large Food and Drugs Act,* that "nonalcoholic flavoring products quantities and have sufficiently low boiling points so that they may be labeled with the term 'flavor,' provided they contain can be removed from the extracted matters a t a low temperathe same kinds and proportions of flavoring ingredients ture under reduced pressure without affecting the quality of as are required by the Department's definitions and stand- the oleoresins. Moreover, their cost is reasonable when it is ards for extracts," and provided they comply with pertain considered that they can be recovered and used over and other requirements. Therefore, when oleoresins or flavors over again. The flasks containing the beans and solvents are prepared with solvents other than ethyl alcohol of proper were closed with rubber stoppers and covered with tinfoil. strength, the question immediately arises as to whether or The finely cut beans were macerated in the solvents for not the oleoresin or the finished flavor has "the same kinds five days or more with frequent mixing, and then separated and proportions of ingredients" as the oleoresins and flavor- from the supernatant liquids by decantation, placed in a ing extracts prepared with ethyl alcohol of proper strength. percolator, and drained, fresh solvent being poured over the It is obvious that considerable information on this question beans to make the volume of the extract up to 200 cc. Two can be obtained by $he analysis of extracts and flavors made additional portions of 25 cc. each of fresh solvent were used by extracting beans, roots, etc., with various solvents. Lab- to wash the beans. A second extraction was conducted in oratory work along this line covering vanilla and tonka beans a similar manner except that the solvents were kept in conwas started in the fall of 1922, and there are submitted here- tact with the beans for 4 weeks or more. There were thus with some preliminary data which are being supplemented obtained forty-eight solutions. The solvents were removed by further laboratory work. The important question of from all the solutions obtained from the two extractions, the toxicity of the solvents was outside the scope of this except those containing 65 per cent alcohol, at a temperature of not over 70" C., and a pressure of 100 to 25 mm. The investigation. quantities of extractive matter obtained are set forth in GEKERAL PROCEDURE I. The various vanilla beans which had been pracTable beans A quantity Of 'Iexican,Bourbon, and Tahiti tically exhausted with 95 per cent ethyl alcohol, isopropyl and Of tonka beans secured from a importing alcohol, ether, acetone, and carbon tetrachloride, were house, cut to about ' 1 4 inch in length With scissors, placed dried in the air and then subjected to the action of in a wooden and divided by Of a 95 per cent ethyl alcohol for 2 weeks and the quantity of meat chopper' One portions were placed in extractive matter determined after removal of the solvent 1 Presented before the Division of Agricultural and Food Chemistry at the temperatureand pressure noted above. These results at the 65th Meeting of the American Chemicaf Society, New Haven, Conn., are set forth also in Table I. The tonka beans, which had April 2 to 7, 1923. been practically exhausted with the solvents just enum2 Service and Regulatory Announcement, Chemistry, 28, Item 391.
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TABLE I-TOTAL EXTRACTIVE MATTERIN VANILLAAND TONKA BEANS,IN PER CBNT (Based on weight of beans) VANILLA-BOURBON VANILLA--TAHITI VANILLA----TONKA--Sum of 1st Sum of 1st Sum of 1st Sum of 1st 1st 2nd a n d 2 n d 3rd 1st 2nd and2nd 3rd 1st 2nd a n d 2 n d 3rdb 1st 2nd a n d 2 n d 3rda 1 EXExExExExExExExExExExExExExExExtractrac- trac- trac- trac- tractractractrac- tractractractrac- trac- tractraction tion tions tion tion SOLVENTS tion tion tions tion tion tion tions tion tion tion .tions 11.9 21.7 1.6 Ethyl alcohol, 95 per cent 13.9 4.5 17.4 4.3 4.2 16.1 5.9 30.3 2.6 18.4 2.1 23.7 6.6 2.2 11.3 6 . 2 Isopropylalcohol, 9 1 p e r c e n t 13.5 4 . 0 17.5 15.9 4.8 20.7 17.4 7.0 24.2 5.1 2.5 18.2 6.0 11.8 7 . 0 8.2 0.8 9.0 11.7 17.5 4.0 21.5 14.5 Ether U. S. P. 10.8 1.0 12.0 13.8 10.0 2.0 3.3 14.5 4.2 9.8 5.0 14.8 13.1 15.3 7.4 11.2 Acetohr, U. S. P. 12.3 3.0 3.2 12.6 3.0 15.6 12.4 13.0 12.1 1.0 0.8 5.8 3.6 16.6 CarbontetrachIoride,99,5percent7 . 6 8.6 8.3 6.6 0.7 7.4 13.8 4.9 Ethyl alcohol, 65 per cent 18.7 . . . . . . . . . . 32.6 . . . . . . . . . . . 24.4 . . . . . . . . . . . 19.8 . . . . Alkaline 65 per cent ethyl alcohol . . . . . . . 20.0 . . . . . . . . . . 30.6 . . . . . . . . . . . 30.7 . . . . . . . . . . . 2 4 . 1 . . . . b Made with 80 per cent ethyl alcohol heated just below boiling for 1 a Made with 95 per cent ethyl alcohol after the beans had been practically exhausted with the solvents enumerated in first column. hour. -MEXICAN
.......
TABLE 11-SOLUBILITY A N D COLOR OF EXTRACTIVE MATTER,IN PERCENT
-
EXTRACTIVE MATTER SOLUBLE
SOLVENTS Ethyl alcohol, 95 per cent IsoDroovl alcohol. 91 Der cent
I N 65 PER CENT ETHYLALcoHoLa Based on Weight of Total Based on Weight of Beans --Extractive Matter-Mexican Bourbon Tahiti Tonka Mexican Bourbon Tahiti Tonka 12 23 13 13 63 77 61 80 10 18 16 11 57 74 80 62
--
COLOROF ALCOHOLIC EXTRACTS--Mexican Bourbon Tahiti Tonka Red Yellow Red Yellow Red Yellow Red Yellow 8 38 12 50 , 5 32 0 2
Alkaline 65 per cent ethyl alcohol a Does not include vanillin.
erated, were subjected to a further extraction with 200 cc. of 80 per cent alcohol by heating just below boiling for 1 hour, the flasks being closed with funnels. The solvent was then removed a t the temperature and pressure noted above and the extractive matter weighed. The extractive matter from the first two extractions was dissolved in 65 per cent alcohol and united. The resulting twenty solutions were then made up to a volume of 1 liter each with 65 per cent ethyl alcohol, mixed, and filtered through a plug of cotton which removed a considerable amount of black, oily material. The filtrates were reserved for extended examination to determine their analytical characters. Those extracts made directly from the beans with 65 per cent alcohol and with alkaline 65 per cent alcohol were also made up to a volume of one liter and reserved for analysis. The total solids on these solutions were determined a t a temperature of 65” C. and pressure of 50 mm., and are reported in Table I1 as “Extractive matter soluble in 65 per cent ethyl alcohol.” These figures do not include vanillin, since the vanillin was volatilized when the extracts were evaporated. I n the case of the alkaline 65 per cent ethyl alcohol solution, the weight of the added potassium carbonate was subtracted before reporting the per cent of total solids. The colors of the final extracts obtained with the‘ Lovibond tintometer are also given in Table 11.
DISCUSSION OF DATA The Bourbon beans yield a considerably larger amount, both of total extractive matter and of extractive matter which is soluble in 65 per cent alcohol, than the Mexican and Tahiti beans with the following solvents: 65 and 95 per cent ethyl alcohol, and isopropyl alcohol. The yields are also larger than hhose from the Mexican beans with the alkaline 65 per cent ethyl alcohol. The Tahiti beans yield a considerably larger amount of extractive matter which is soluble in 65 per cent alcohol than the Mexican beans with the following solvents: 65 and 95 per cent ethyl alcohol, isopropyl alcohol, and alkaline 65 per cent alcohol. Therefore, the beans may be rated in the following order-namely, Bourbon, Tahiti, and Mexicanfrom the standpoint of yield of extractive matter soluble in 65 per cent alcohol, with the solvents enumerated above. Ether and carbon tetrachloride dissolve out much less total material from the Mexican, Bourbon, and Tahiti beans than the alcoholic solvents. The total extractive matter obtained with acetone is in all cases less than that obtained
with the alcoholic solvents, but is substantially more than that obtained with ether and carbon tetrachloride. However, so little of the total extractive matter obtained with ether, acetone, and carbon tetrachloride is soluble in 65 per cent ethyl alcohol, that it appears a t this time the use of any of these three solvents is impracticable unless the beans after being exhausted with these solvents are subjected to action of other solvents. The largest amount of extractive matter soluble in 65 per cent alcohol was obtained with acetone and was 8 per cent, whereas the lowest apount obtained with the alcoholic solvents was 10 per cent and the highest amount was 33 per cent. However, the complete evaluation of the quality of the extractive matter is not yet accomplished, and it may be that one or another of these three solvents will make a somewhat better showing from the standpoint of quality than they have from the standpoint of quantity. At the present stage of the investigation the alcoholic solvents are shown to be much superior. It is interesting to observe that carbon tetrachloride extracts from the beans less than 1 per cent of material (exclusive of vanillin) which is soluble in 65 per cent ethyl alcohol and practically no color which is soluble in 65 per cent alcohol, but does extract a substantial amount of a dark red, viscous, oily material which is insoluble in 65 per cent alcohol. This insoluble material is practically tasteless, and possesses a fatty odor which became rancid on standing. Its saponification numbers were as follows: Mexican, 82; Bourbon, 111;Tahiti, 94. In the authors’ opinion this material has little or no value as a flavor, although their attention has been called to a patent3 the claims of which indicate that certain insoluble material obtained under somewhat the same conditions has a substantial flavoring value. It is reported4 that in the preparation of a pure extract the use of alcohol weaker than 45 per cent is not commercially practicable owing to difficulties in percolation. A process which involves a preliminary extraction with carbon tetrachloride, followed by extraction with a weak alcoholic solution, is promising, since it is believed that the removal of the black, oily material will facilitate subsequent percolation. This process is now being subjected to a special investigation. ‘ About the same quantities of total extractive matter are obtained from tonka beans by each of the solvents. HOWever, the alcoholic solvents yield more extractive matter that is soluble in 65 per cent alcohol than does ether, acetone, 3 4
U. S. Patent 931,805 (August 24, 1909). Leach, “Food Inspection and Analysis,” 4th ed., p 914.
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or carbon tetracliloride.
Here, too, there is a possibility
of obtainine an advantage by making a preliminary extrac-
tion of the beans with ether or carbon tetrachloride, and a subsequent extraction with a weak alcoholic solution. The analytical characters of the final extracts are now being
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determined and it is proposed also to determine the relative flavoring quality of the extracts made with the different solvents by comparing the taste of custards, junket, cakes, beverages, and other edible material to which the extracts have been added.
Adsorption of Color from Sugar Solutions by Chars’ By Marshall T. Sanders ATLASPOWDER Co., WILMINGTON, DEL.
T THE fall meeting of this SOCIETY in 1921, F. W. Zerban presented a paper in which he showed conclusively that the action of decolorizing carbons in removing color from sugar and molasses solutions can be expressed by Freundlich’s adsorption equation X / M = KC1/n, where X = the amount of solute adsorbed by M grams of carbon, C is the concentration of the solute at equilibrium, and K and n are constants. He further showed that the “color units” proposed by Meade and Harris2 could be used in place of the concentration terms X and C. Unfortunately, Dr. Zerban has not as yet published this paper. At this laboratory it has also been found that the color removal by vegetable carbons follows the Freundlich equation in the cases of sugar and molasses solutions. Plate I shows the relation between the percentage of color removed from a certain molasses solution and the weight of the carbon used. Since 2 grams of carbon do not remove twice as much color as 1 gram, it is obvious that the carbon did not do as much work per gram when the larger quantity was used as it did with the smaller quantity. The term X / M in the Freundlich equation is really the work done by a unit weight of carbon. This equation states that the work done by a unit weight of carbon ( X / M ) is proportional to some power of the concentration of the solute at equilibrium.
A
7oc
/‘
,
preparing Plate I, with the exception that in Plate I1 color units are used instead of percentage of color. Curve C, Plate IV,is for the data in Plate I, with the color expressed as per cent. Any errors in determining the color of the solutions a t the left-hand end of the curve cause approximately a horizon/DO0
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PLATE L?’ /U
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psper is given in Plate 11 for the same data as were used in Prevented before the Division of Sugar Chemistry at t h e 65th Meeting of t h e American Chemical Society, New Haven, Conn., April 2 t o 7,
PLATE LT
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