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Evaluation of Commercial Vanilla Oleoresins’ By J. B. Wilson and J. W. Sale WATER
AND
BEVERAGE LABORATORY, BUREAU OF CHEMISTRY, WASHIKGTON, D. c.
HE nature of vanilla oleoresins is such that it is very 0.7 per cent; glycerol, 13.8 per cent. One hundred grams of difficult to detect, by inspection or by use, adulteration this mixture represents 70 grams beans. This sample was with glucose, caramel, vanillin, etc. A large amount designated G. The caramel used in this sample was a comof work has been done upon the analysis of genuine and imi- mercial preparation and is designated H in the table. tation vanilla extracts, but a number of the methods used for Commercial Oleoresins the analysis of those products are obviously not applicable Five samples of widely distributed brands of commercial to the examination of’ vanilla oleoresins without considerable modification. Moreover, the literature does riot contain oleoresins were purchased on the market. Thev were desinnated I , J,K,”L,and M , r’3d i r e c t i o n s for preparing s p e c t i v e l y . No informavanilla oleoresins for analytion was available as to the sis, nor could data belocated Vanilla oleoresins are employed as a base for the methods of manufacture of which would assist in intermanufacture of flavors and have been articles of comthese samples. They were preting analyses of these merce for many years, but the literature on flavoring dark brown or black. I , J , products. This investigamaterials indicates that food officials have given but and K were very viscous, tion was conducted with a little attention to the detection of their adulteration. but L and M poured readily, view to determining suitable In this investigation authentic vanilla oleoresins for On standing all but L sepamethods of analysis and the use as standards were prepared by extracting three rated into two layers, the significance of the analytical varieties of beans with a suitable solvent and removing lower of which mas very visdata. the solvent under reduced pressure. These authentic c o u s , h e a v y and almost samples, together with commercial vanilla oleoresins, Preparation of Authentic black, while the upper layer Vanilla Oleoresins were prepared in different ways for analysis, and the was less viscous and lighter resulting products were subjected to analysis. The Alexican, Bourbon, and in color. M c o n t a i n e d significance of the analytical data is discussed and, Tahiti vanilla beans were numerous small granular finally, those methods of analysis which proved to be cut m-ith scissors into pieces lumps. Vigorous shaking useful in evaluating the commercial samples are listed. about 13 nim. (0.5 inch) in was required to secure even length, placed in a wooden distribution of these lumps. bowl, and finely divided by Preparation of Samples for Analysis means of a meat chopper. The cut beans were exhausted with 47.5 per cent ethyl alcohol, which is the strength recommended Preliminary experiments indicated that it would be necesby the Research Committee of the Flavoring Extract Manufacturers’ Association.* The extracts were Concentrated in sary to use more than one solvent in preparing the samples partial vacuum (*25 mm. Hg) t o a density approximating for the various determinations and, as i t was not known 1.3 a t 25’ C., which is about the consistency of commercial which solvent would be the most suitable for a particular vanilla oleoresins. One hundred grams of tht: oleoresins determination, all samples of oleoresins were extracted with obtained in this way represented the extractive matters from the following solvents: (1) 95 per cent alcohol; (2) 47.5 the following weights of beans: Mexican, 220 grams; Bour- per cent alcohol; and (3) 95 per cent alcohol followed by water. bon, 170 grams; Tahiti, 185 grams. These oleoresins were The extractions were made by adding in succession two designated A , B, and C, respectively, and were used as stand- and, when necessary, three portions of the solvent to a ards. The analytical data obtained on them are set forth weighed amount of the sample and boiling the mixtures for one-half hour in a flask fitted with a reflux condenser. All in the accompanying table. T w o other authentic oleoresins were prepared by making two the resulting solutions were analyzed and the analytical data extractions of finely divided Bourbon beans with menstruums compared for the purpose of selecting the proper solvent consisting of (1) 65 per cent alcohol, (2) 65 per cent alcohol for each determination. I n some cases-as, for example, and 12 per cent glycerol, and concentrating as previously in the determination of ash and ash constituents-portions described. One hundred grams of these oleoresins represent of the well-mixed samples were weighed and analyzed. 300 and 79 grams beans, respectively. These two samples Methods of Analysis were designated D and E, respectively. The partially extracted beans used in making oleoresins The determination of saponification number and of acidity D and E were exhausted with 47.5 per cent alcohol. The in vanilla oleoresins is not reliable because of the presence of extract was concentrated as described above and the resulting sugars, caramel, nitrogenous matter, etc., which react with oleoresin mas designated F . One hundred grams of this alkali. Iodine number is affected by the presence of water. oleoresin represents 300 grams of partially extracted beans. Several methods of absorbing the water from the oleoresins, A portion of the standard oleoresin B made from Bourbon -viz., by the addition of anhydrous sodium sulfate and acetic beans was mixed with caramel, vanillin, coumarin, and glyc- anhydride-were tested, but concordant results could not be erol in such proportions as to have the following calculated obtained. An oxidation m e t h ~ d which ,~ was recommended composition: Bourbon vanilla oleoresin B, 41.4 per cent; for the determination of sugar and glycerol in nonalcoholic caramel, 41.4 per cent; vanillin, 2.7 per cent; coumarin, flavors, was tested but found to be inapplicable to vanilla Presented before the Division of Agricultural and Food Chemistry oleoresins because of the interfering action of caramel which at the 68th Meeting of the American Chemical Society, Ithaca, N. Y . . Sepmay be present as an adulterant in this class of products. tember 8 to 13, 1924. Recelved January 19, 1926.
T
1
2
Tea and C o f e e T r n d e J . , July, 1924, p. 121.
3
Hoyt and Pernberton, THISJOURNAL, 1 4 , 54 (1922).
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The methods employed in analyzing these samples of oleoresins and the references to the literature where they may be found, are listed below:
Vol. 18, S o . 3
J and M fall outside these limits. It is interesting to note that sample G, which is adulterated with glycerol and cara-
mel, falls within the limits because of the compensating effect of these two adulterants. However, in general, these Nonvolatile solids at 100’ C. Assoc. Official Agr. Chem., determinations are shown to be of value. Methods, Revised to July 1, 1924, XIII, 4, p. 178. Vanillin. Folin and Denis, THISJOURNAL, 4, 670 (1912). VANILrm-In several samples-namely, A , G, H , J , and Vanilla resin. Report on Flavors and Nonalcoholic Beverages, presented at October, 1925, meeting of the A. 0. A. C. K-the vanillin found in the extract containing 47.5 per cent alcohol (line 8) is substantially higher than that in the 95 13, 414 (1921). Wichmann’s lead number. THISJOURNAL, Glycerol. Assoc. Official Agr. Chem., Methods, Revised t o per cent alcohol (line 7). As sample H was a commercial July 1, 1924, XXVII, 3, p. 349. sample of caramel which contained no vanillin, these data Caramel. See below. indicated that caramel interfered with the determination of Ash. Assoc. Official Agr. Chem., Methods, Revised to July vanillin by the method which was used-namely, the Folin 1. 1924, IX. 7, p. 116. Alkalinity of soluble and of insoluble ash. Ibid., X I I I , 13 and Denis method. To test this, four commercial samples and 14, p. 180. of caramel were analyzed by the method in question, the rePhosphate. Ibid., I, 8-10, p. 3. sults showing that they apparently contained 4.32, 4.06, Potash. Ibid., I, 43-5, p. 13. 0.78, and 0.58 per cent vanillin. These data were obtained The method used for the determination of caramel is a mod- on solutions containing 5 per cent of caramel and 47.5 per cent ification of the Amthor test4and is as follows: of alcohol. However, when the method was applied to a soluDETERMINATION OF CARAMEL-The weighed samples were tion of caramel in 95 per cent alcohol, negative results mere extracted with 95 per cent alcohol as described under “Preparation of Samples for Analysis” and t h e extracted residue was dis- obtained. It is apparent, therefore, that when the Folin solved in water and filtered. The filtrate was evaporated t o and Denis method is used to determine vanillin in vanilla sirupy consistency and cooled. Fifty cubic centimeters of par- oleoresins which may be adulterated with caramel, the aldehyde and sufficient 95 per cent alcohol t o cause the water and sample should be extracted with 95 per cent alcohol and not paraldehyde t o mix thoroughly were added and, after stirring, 47.5 per cent alcohol. The error will be materially less, the mixture was allowed to stand overnight. The supernatant owing to dilution, when the method is applied to vanilla exliquid was then decanted carefully through a filter moistened with alcohol and t h e precipitate in the beaker washed by de- tracts colored with caramel and may not be appreciable cantation twice with a few cubic centimeters of 95 per cent al- in the case of extracts. cohol. T h e precipitated caramel on t h e filter and in t h e beaker The ratio of vanilla resin in extract 47.5 per cent alcohol was dissolved in hot water and t h e solution obtained was evapo(line 10) to vanillin in extract 95 per cent alcohol (line 7) varated t o dryness in a weighed 50-cc. beaker. The residue was dried at 100’ C. and t h e dry caramel reported in terms of per ries from 1: 1 to 1:5 in authentic samples A , B, and C. The cent based on weight of oleoresin taken. ratios on all the other samples except G, H , and J fall within these limits. As sample G is adulterated with vanillin, this I n t e r p r e t a t i o n of Analytical D a t a ratio is useful in determining the addition of vanillin to comThe analytical data obtained in the investigation are set mercial samples. forth in the table. The figures in the first three columns, VANILLAREsIN-The data on the extract made with 95 representing the authentic oleoresins to be used as standards per cent alcohol (line 9) agree fairly well with those on the in evaluating the other samples, are expressed in terms of extract made with 47.5 per cent alcohol (line 10) except that 10 grams of beans and are therefore comparable with those on some samples, especially J, the figures are higher for the obtained on a standard vanilla extract16the analytical data on extract made with 47.5 per cent alcohol.. The total ash which are usually expressed in terms of 100 cc. equivalent to (line 14) and potash (line 21) indicate that sample J was 10 grams of beans. made by the use of potamium carbonate. Evidently, the The analytical data on samples A , B, and C could have been alkali salts of the acid resins are more soluble in 47.5 per cent expressed in per cent based on weight of oleoresin, as are the alcohol than in 95 per cent alcohol. For this reason and for data on the other samples. However, this would imply that the further reason that the amounts of vanilla resins found standard Mexican, Bourbon, and Tahiti oleoresins should rep- in samples A , B, C, and H containing 47.5 per cent alcohol resent the proportions of beans used in the preparation of these are more nearly like those in true vanilla extracts than the samples, a n assumption which was deemed inadvisable, corresponding figures for the extracts containing 95 per cent The data on samples D, E , F , and G could have been expressed alcohol, it is advisable to employ only 47.5 per cent alcohol in terms of weight of beans, but these samples were regarded for this extraction. as of unknown origin in order to check the method of evaluaWICHMANN LEADXUMBER-This determination was made tion. The data on the commercial samples I , J, K, L,and only on the extract containing 47.5 per cent alcohol, because M could not be expressed in terms of weight of beans, since previous work by the &-iter@ had shown that the lead the methods of manufacturing these samples were unknown. NONVOLATILE SoLIDs-The data show that the deter- number is due chiefly to water-soluble constituents and data minations of nonvolatile solids on the oleoresin itself and on obtained on an extract made with 95 per cent alcohol would the 47.5 per cent alcoholic extract of oleoresin (lines 1 and 3) not be comparable with those obtained on commercial vanilla are of little value in the presence of glycerol or caramel, extracts which are always made with alcohol much more since samples E, F , G, and H , which contain substantial dilute than 95 per cent. The Wichmann lead numbers on amounts of caramel or glycerol, gave results on these deter- samples E and G (line 11) are low because, as previously minations which were not much different from the unadul- mentioned, 100 grams of these samples represent only 79 and 69 grams beans, respectively, owing to presence of large terated samples. amounts of glycerol and caramel. The low lead numberThe ratios of nonvolatile solids on the extract 95 per cent alcohol (line 2) to nonvolatile solids on water extract (line 4) namely, 2.7-on the commercial sample of caramel H shows vary on the authentic samples A , B , and C from 0.5:l to 2:l. that caramel does not materially affect this determination. The lead number on sample J is abnormally high, because Samples E and F , which are adulterated with glycerol, the this sample was made with alkali. The low figure for lead sample of commercial caramel, H , and commercial samples number on sample M indicates that this sample was made 4 Assoc. Official Agr. Chem., Methods, Revised t o July 1, 1924, XXIX, with alcohol of a strength greater than 47.5 per cent. 48, p. 374. 6
U. S. Dept. Agr., Circ. 186.
e
THISJOURNAL, 16, 301 (1924).
March, 1926
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Composition of Vanilla Oleoresins (Caramel included for comparison) AUTHENTIC OLEORESINS USED AS STANDARDS" AUTHENTIC MADE hlexi- Bour- TaOLEORESINS can bon hiti F R O M BOURBON BEANS" CARAMEL-COMMERCIAL D E F G H I J A B C Grams per 10 grams beans 7 0 %
OLEORESINS--
K
L
M
DETERMIXATTON % % % h-onvolatile solids:b 74.2 60.4 48.8 L 8 4.0 3.2 73.9 6 6 . 2 6 8 . 7 71.3 73.6 6 1 . 1 6 4 . 0 Total 1 7 3 2 . 6 3 3 . 6 34.0 ;..o 2 . 0 2 . 2 41.8 6 5 , s 53.2 35.5 1 4 . 0 3 0 . 9 1 1 . 0 Extract 95% :alcohol 69.4 60.1 4 7 . 0 69.8 58.3 52.9 62.6 63.4 53.1 61.9 J.1 4.0 3.5 3 Extract 47.5?5 alcohol 2 3 . 1 4 9 . 8 31.6 24.0 10.6 3 0 . 9 2 . 6 1 3 . 3 3 0 . 3 5 5 . 2 L.9 1 . 6 1 . 2 Water extractc ? 3.3 1.8 1.3 0.3 0.7 1.1 0 . 1 0.6 0.2 0.2 Insoluble in 9570 alcohol a n d in water 0 . 0 3 0.05 0 . 0 2 2 . 1 4 . 3 6 . 7 2 . 8 1.0 0.1 1 . 2 0.5 0 . 2 0 . 3 0.00 0.04 0 . 0 1 6 Insoluble in 47,5y0 alcohol Vanillin : 3.2 2.6 6.2 2.3 4.3 4.9 0.0 4.3 4.1 5.1 0 . 1 4 0.32 0 . 2 2 Extract 95% alcohol 4.2 6.3 3.3 3.5 4.3 5.1 6.6 2.2 4.4 5.0 (1.24 0 . 3 5 0 . 2 6 8 Extract 47.557,, alcohol Vanilla resin: 0.6 0.1 2.4 1.1 2.0 0.8 2.6 1.6 1.5 0 . 0 7 0 . 0 9 0.08 2.1 9 Extract 9 5 7 ;alcohol 2.0 5.1 2.9 0.8 1.3 1.5 2.6 0 . 1 3 0 . 1 5 0.04 10 0.1 0.0 Extract 47..?53 alcohol 2.6 8.i 2 . 7 17.4 33.0 5.9 15.3 2 1 . 2 1 9 . 8 12.8 17.9 11 Wichmann's lead number in extract 4 7 . 5 5 alcohol 1 , 4 8 0 . 9 8 1 . 2 2 0.0 2.1 4.4 (1.22 0 . 2 0 0 . 2 0 5.6 3.2 3 . 8 36.7 2 7 . 9 11.0 4.2 12 Glycerol in extract 95% alc ohol 9 . 1 25.8 37.8 11.0 34.1 13.8 12.8 5.4 8.3 0.3 L.34 0 . 9 5 0 . 7 2 13 Caramel in water extractc Ash: 5.78 2 . 0 0 5.40 4 . 0 7 3.17 8 . 7 5 22.76 9 . 6 6 7.20 4 . 6 1 Total 0.28 0 . 3 8 0.39 14 6 . 2 8 18.29 4.89 6.28 4.29 2.53 7.84 5 . 3 7 3 . 5 5 0.22 0.30 0.32 Water-soluble 15 2.47 4.47 0.89 0.42 1 . 1 1 1 . 5 4 1 . 8 1 1.83 1 . 0 6 0.06 0.08 0.08 Water-insoluble 16 1.43 1.12 1 . 7 3 0 . 8 3 0.18 2 . 4 7 2.54 2 . 3 3 2.36 1.92 0.13 0 . 0 5 0.09 Extract 95% .alcohol I i 6.09 4 . 8 3 3 . 2 0 2 . 7 8 8.62 19.28 9.66 8.15 0.33 0.34 Extract 47.55; alcohol 19 3 . 1 4 2 . 9 2 2 . 8 9 5 . 6 4 16.37 6.27 5.15 2.82 0 . 4 3 0.27 0.24 Water extractc 19 0.33 0.11 0.37 0.19 0.03 0.48 0.94 0 . 4 4 0.38 0 . 2 3 11.02 0 . 0 2 0 . 0 3 Phosphate (P:!Od -00 3 . 3 4 9.72 2.74 0 . 8 9 2 . 3 3 1 . 3 0 4 . 2 5 3.13 2.08 0 . 1 4 0.18 0 . 1 9 Potash (KzO) 21 Cc. 1 h'acid per 10 g. beans Cc. 1 S acid per 100 g. oleoresin Alkalinity ash: 58 I52 68 3.1 3.7 48 33 2!,5 22 Water-soluble 26 10 28 46 79 49 39 1.1 1.7 1.8 21 Water-insoluble 23 These samples were prepared as follows: A-Beans extracted with 47.57' alcohol. 100 grams oleoresin represent 220 grams beans. B-Beans extracted with 4 7 . 5 8 alcohol. 100 grams oleoresin represent 170 grams beans. C-Beans extracted with 47.57, alcohol. 100 grams oleoresin represent 185 grams beans. 100 grams oleoresin represent 300 grams beans._ D-Beans extracted with 65y0 alcohol. E-Beans extracted with 66% alcohol and 12% glycerol. 100 grams oleoresin represent ( 9 grams beans. F-Partially extracted beans from D and E extracted with 47.6% alcohol. 100 grams oleoresin represent 300 grams partially exhausted beans. &Sample is a mixture of vanilla oleoresin B , cartrmel, vanillin, coumarin, and glycerol. 100 grams of C represent 70 grams beans, with a total calculated vanillin content of 4.97,. b Dried a t 100' C. E Oleoresin previously extracted with 95% alcohol. Line
GLYCEROL . ~ N DCARamx,-Samples E, F , and G (line 12) beans TT-hich are represented by commercial samples I , J , contained added glycerol, The figures reported as glycerol K , L, and M. on the other samples probably do not represent glycerol R e c o m m e n d e d M e t h o d s of Analysis but only material obtained by the method of analysis which I n view of the data obtained in this investigation, it is was employed, since the material did not have the appearance of glycerol or the odor of glycerol on ignition. recommended that the following procedure be followed in The caramel (line 13) was determined on the water extract analyzing commercial vanilla oleoresins : Make the determinations listed below, following the proof the material insoluble in 95 per cent alcohol. This procedure is preferable to direct extraction of the oleoresin with cedure employed in this investigation. water, which is difficult to accomplish. The figures for 1-On t h e well mixed oleoresin caramel should not be given undue weight until the method (a) Ash ( b ) Total alkalinity of ash which was used has been further investigated, but it is 2-On a n extract of t h e oleoresin in 95 per cent alcohol evident that the figures for samples G and J indicate the pres( a ) Nonvolatile solids (at 100' C.) ence of added caramel. Of course, added caramel was known ( b ) Vanillin t o be present in sample G. fc'i Glvcerol 3-On the watkr extract of t h e oleoresin after extraction with ASH h ? ; ~ ASH CoXsTITui~NTs-The determination of total 95 per cent alcohol ash (line 14) is useful because it shows whether or not the (a) Xonvolatile solids (at 100' C.) sample is made with alkali, but the determinations of water( b ) Caramel soluble ash, water-insoluble ash, ash in extracts made with 95 4-On an extract of t h e oleoresin in 47.5 Der cent alcohol ( a ) Vanilla resin per cent and 47.5 per cent alcohol, and ash in water extract ( b ) Wichmann lead number (lines 15 to 19, inclusive) apparently give no additional information of value. Caramel (sample H ) , of course, contains Express the total alkalinity of ash as cubic centimeters of substantial amounts of total ash. The ratio of total ash to 1 N acid per 100 grams oleoresin. Express all other results total alkalinity of ash-that is, cc. 1N acid per gram of ashin per cent based on weight of oleoresin. Calculate ratio in authentic samples A , B, C, and D varies from 1 :12 to 1:14. of ash to total alkalinity of ash, ratio of nonvolatile solids All the samples except G, H , and J fall within these limits. on the extract 95 per cent alcohol to nonvolatile solids on Sample G is known to be adulterated, sample H is com- the water extract, and ratio of vanilla resin in extract 47.5 mercial caramel, and sample J was undoubtedly made with per cent alcohol to vanillin in extract 95 per cent alcohol. alkali and adulterated with caramel. Under the circumAcknowledgment stances, it is believed that this ratio is worthy of consideration in evaluating this class of product. The phosphate and The authors acknowledge the assistance of C. H. Badger, potash figures do not appear to give any information addi- of the Water and Beverage Laboratory, in the analytical work. tional to that conveyed by total ash and total alkalinity of ash. PROPORTION OF BEANS REPRESENTED BY COMMERCIAL Pyrazolon, a coal-tar intermediate used in the preparation of dyes, was recently held by the United States Court of Customs SAMPLES OF OLEoREsrss-The data in the table show that it Appeals t o be dutiable a t the American selling price of a comis impracticable to attempt to calculate the proportion of petitive domestic product.
