July, 1916
607
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 C H E M I S T R Y
the heated and t h e corresponding unheated samples. T h e f a t t y free acids a n d t h e total acidity, however, are in each case higher in t h e heated samples t h a n in the unheated ones. The free f a t t y acids remained in t h e latter within 0.45 per cent of t h e mean for these samples-2.06 per cent-but the free f a t t y acids in the heated samples increased from 2 . 7 0 per cent in No. 2 1 3 0 t o 11.89 per cent in No. 21j4. T h e total acidity varied in t h e same way as t h e free f a t t y acids. The minimum for t h e unheated seed was 26 cc. of normal alkali per kilogram of seed with NO. 2 1 2 3 , t h e maximum 3 2 cc. with S o . 2128, and t h e average 28 cc. For t h e heated seed t h e minimum was 32 cc. with No. 2 1 2 7 . the maximum 91 cc. with NO. 2154. and the average 51 cc. The total acidity of the unheated samples increased only slightly with increase in length of storage, while t h a t of the heated seed increased about 300 per cent. A sample taken from the unheated area a t t h e end of t h e storage period-So. 2 1 71-contained only 2.43 per cent free f a t t y acids and 2 7 cc. acidity, figures essentially the same as those obtained on the freshly ginned seed of this lot. Samples from two lots of cottonseed-Xos. 1 g 9 j and 2016-sampled a t harvest and stored in t h e laboratory for I j mos. showed 1.6 j and 1.75 per cent free f a t t y acids in f a t and 26 and 38 cc. total acidity. Samples of t h e same lots of seed stored in a seed bin for 3 mos. and then kept in the 2040 laboratory for 1 2 mos. before analysis-Nos. a n d zo4z-showed 1.78 and 3.43 per cent free f a t t y acids in f a t , and 40 and j o cc. acidity, respectively. Increase in acidity and free f a t t y acids in stored cottonseed is due t o t h e heating of t h e seed a n d not t o aging. D r y cottonseed may be kept for a year or longer without deterioration. SUMSIARY AND C O N C L U S I O K S
I-Dry cottonseed stored in an oil mill seed house in a jooo lb. lot in a pile 1 2 f t . b y 1 2 f t . b y 6 f t . , dried out in storage and t h e n heated. During t h e heating the free f a t t y acids increased nearly 500 per cent, and the total acidity nearly 375 per cent. There was no apparent tendency for the protein t o hydrolyze during t h e storage period. 11-Even a short heating of cottonseed causes the hydrolysis of about I O per cent of t h e f a t of cottonseed, and an increase in t h e total acidity. while long heating or storage of heated seed in t h e absence of air may cause 7 0 per cent of t h e f a t , and 33 per cent of t h e protein t o hydrolyze, and lead t o t h e production of 7 0 0 per cent more total acidity t h a n normal seed contains. Such cottonseed is worth little except as a source of soap stock and fertilizer. 111-The source of t h e acidity of fresh cottonseed is t h e f a t only in part, b u t in heated cottonseed i t is probably t h e f a t almost entirely. Free f a t t y acids in fresh samples of cottonseed averaged less t h a n 2 per cent of t h e f a t . and t h e total acidity not more tha? 2 6 cc. in terms of normal alkali per kilogram of cottonseed. IV-Increase in the acidity a n d t h e free f a t t y acids in stored cottonseed is due t o heating and not t o t h e aging of t h e cottonseed. ARKANSASEXPI~RIMENT STATION,FAYETTEVILLE
VANILLA EXTRACT’ B y J. R. DEAN AND J. 0.
SCHLOTTERBECK~
Received January 3, 1916
Before going into a discussion of the tincture or extract of vanilla, it seems logical t o consider, for a moment, t h e composition and nature of t h e crude material from which t h e extract is prepared. The vanilla bean is t h e source of vanilla extract a n d is t h e fruit of t h e plant Vanilla planijolia (Andrew). This climbing, perennial plant belongs t o t h e orchid family and is indigenous t o Central and South America a n d t h e West Indies, b u t is cultivated also in Reunion, Seychelles, Madagascar, Comores, Ceylon, Java a n d Tahiti. The most highly prized beans are cultivated in Mexico in the vicinity of Vera Cruz. While the different varieties differ in some details, t h e best cured beans of commerce, as a rule, are from 8 t o I O in. ( 2 0 t o 2 j cm.) in length and from 1 1 8 t o of a n inch (4 t o 8 m m . ) thick, drawn out at their ends and curved a t t h e base. They are rich dark brown in color, of a waxy nature t o t h e touch, deeply rifted lengthwise, a n d are often covered with frost-like crystals of vanillin. COMPOSITION O F THE BEANS
T h e beans contain vanillin, secondary compounds, resins, organic acids, volatile oil, sugar, gum, tannin, wax a n d water. centage analysis of two varieties of beans, t o Konig, is as follows: I 25.85 ies... , . . . . . , . . . 4.87 . . . . _ . . . . 7.07 . . . . . . . . . 6.74 , . . . . . 30.50 Ash ...........................
4.73
aromatic oil, fixed T h e peraccording
I1 30.94 2.56 9.12 4.68 32.90 4.53
Vanillin is included in the above table under t h e “non-nitrogenous bodies ” and is the chief flavoring agent of the bean. Chemically, vanillin is t h e methyl ester of protocatechuic aldehyde. I t is soluble in hot water, alcohol, ether, chloroform and some volatile oils, b u t only slightly so in cold water. At 8 1 t o 82’ C.,vanillin melts a n d sublimes at high temperatures without decomposition. Heated in a current of carbon dioxide, vanillin can be distilled under pressure of I j mm. of mercury. It is present in vanilla beans t o a n amount vary,ing from I t o 3 per cent, a n d , curiously enough, t h e higher prized beans do not contain the most vanillin. This has been shown b y Tiemann and Haarmann3 as follows: BEANS Per cent Vanillin.
,
..
Mexican 1.69
....
Bourbon 2.48
Java 2.75
T h e green vanilla beans do not contain vanillin a n d are devoid of t h e fragrance of the ripe and cured beans. Vanillin is formed in the bean during t h e process of curing b y hydrolysis from coniferin, a glucoside found in various parts of t h e plant and elsewhere in t h e vegetable kingdom. Coniferin is first split 1 A report of t h e work done during 1914-15 a t the University of Michigan on the Fellowship granted for t h e purpose b y the flavoring Extract Manufacturers’ Association and published b y them in September, 1915, in the minutes of their 6th Annual Convention, held in Cleveland, Ohio, in July, 1915. 2 College of Pharmacy, University of Michigan, Ann Arbor, Mich. 8 Bev., 8 (1875). 1118; 9 (1876). 1287.
T H E J O U R N A L OF INDUSTRIAL A N D ENGINEERING CHEMISTRY
608
into coniferyl alcohol a n d glucose b y means of a n enzyme. The coniferyl alcohol is t h e n oxidized t o vanillin b y a n oxidase present in t h e beans. T h e beans are cured naturally if left on t h e vines, b u t t h e ’ beans cured on t h e vines are not as fine as those which are pulled green a n d cured b y artificial means. The curing process consists of repeated smeatings a n d dryings obtained b y t h e heat of t h e tropical s u n . I n some of t h e other countries, especially in Reunion, t h e beans are cured b y dipping into hot water a n d then drying. The former, or Mexican process, is said t o produce a much finer bean t h a n t h e l a t t e r , which is often called t h e Bourbon process. It has been possible t o obtain vanillin from other parts of t h e vanilla plant t h a n t h e beans. This has been shown by Jos. Behrens, who was able t o obtain vanillin from t h e leaves of t h e vanilla plant b y hydrolysis with dilute acid.’ T h a t the production of vanillin in t h e bean is a n enzyme action has been shown b y obtaining two green beans from Mexico a n d heating one t o 80’ C. in order t o destroy t h e natural enzyme present, and t h e n submitting both beans t o a curing process. T h e bean which had not been heated produced vanillin while t h e heated one did not. The chemical reaction occurring during t h e formation of vanillin in t h e bean is supposed t o be as follows : CItjH2208 HZO = C10Hi203 CEHSO~ Coniferin Coniferyl alcohol Glucose 3 0 2 = CsHsOB z H ~ O zCO CIOH1SOI Coniferyl alcohol Vanillin Vanillin was first separated from vanilla beans i n 1858 by Gobley a n d first prepared synthetically by Tiemann a n d Haarmann in 1874~from coniferin b y means of chromic acid. T h a t t h e value of vanilla beans cannot be determined b y their vanillin content has long been known a n d is evident from t h e fact t h a t t h e most highly prized varieties do not contain t h e most vanillin. The chemical reaction which produces t h e vanillin i n t h e beans is believed b y some t o continue evkn after t h e beans are tied up into bundles. This would account for t h e well known custom of storing t h e beans for one or two years after being received from t h e plantation. I t might be of interest also t o know t h a t vanillin is not limited in nature t o vanilla beans alone b u t t h a t it is found in Siam benzoin,3 in a ~ a f o e t i d a i ,n ~ crude beet sugar,5 in asparagus,G in dahlia tubers,7 a n d in many other plants, in resins, in balsams, a n d other substances. Synthetic vanillin is produced on a large scale a n d is identical with t h e natural product. I t was first made from coniferin b y oxidation with chromic acid. NOW it is largely obtained from the eugenol or oil of cloves b y means of alkaline, potassium permanganate. s E c o N D A R Y A 11 o MIATIc c o L i p o ‘c X D s---I t is well known t h a t a n extract of vanilla beans is superior i n flavor t o a simple solution of vanillin, a n d it is claimed t h a t
+ +
Trogenplanzev. 1899, 299. Ber.. 8 (1875), 1123. 3 I b i d . , 11 (1878), 1635. 4 fbid., 19 (18861, 705. 5 Ibid., 13 (ISSO), 335, 662. 6 Ibid., 16 (1883), 44, 18. 7 Ibid., 39 (1906), 4147. 1
+
+ +
1-01. 8, No. 7
t h e additional flavor of t h e extract is due t o several secondary aromatic flavoring compounds which are present in t h e beans i n very small amounts. This additional flavor has been said t o be due t o piperonal (heliotropin),’ a n d others claim t h e presence of several other aromatic aldehydes, alcohols a n d esters. B u t besides t h e statement t h a t piperonal is present, there is no definite scientific statement t o be found in t h e literature in regard t o either t h e Mexican or t h e Bourbon beans. Walbaum has separated anisic aldehyde, anisic alcohol a n d anisic acid from Tahiti beans, a n d has denied t h e presence of piperonal in Tahiti beans.? The whole complex of t h e secondary flavoring compound is often spoken of as t h e “ B a l s a m ” of t h e beans, a n d i t i s no doubt made up of a large number of compounds more or less different i n t h e different varieties of beans if not also in t h e different lots of t h e same beans. A volatile oil has been obtained from vanilla beans, b u t no more can be found in t h e literature about it. t h a n about t h e secondary flavoring compounds; i t is no doubt a p a r t of t h e balsam. REsIr;--The resins of vanilla beans are said b y some investigators t o be present i n amounts varying from 4 t o 18 per cent, while others say t h a t t h e y are present in a n amount equal t o t h a t of t h e ani ill in.^ They mere at one time thought t o be of great flavoring value and t o make t h e differencebetween a n extract of vanilla and a simple solution of vanillin. This has been disproven lately, however, a n d it is now known t h a t these bodies, whatever t h e y are, are odorless a n d have a n y thing but a pleasa.nt taste.4 We are able t o separate a dark red sticky substance t h a t was soluble i n alcohol a n d alkalies a n d insoluble i n water t h a t seemed t o US as being t h e substance usually called t h e resins. T h e alcoholic a n d alkaline water solutions of t h e substance were dark red in color. The alkaline water solution was slightly acidified with acetic acid a n d lead acet a t e was added when a precipitate was obtained t h a t was in every respect similar t o t h e precipitate obtained in t h e lead number determinations. This substance was tasteless a n d odorless. It has been claimed t h a t vanilla beans contain two different resins, one acid a n d t h e other neutral.5 Bbsolute alcohol dissolves a yellowish substance from t h e beans t h a t is not soluble in dilute alcohol a n d it is not possible t o obtain t h e coloring matter of t h e beans in absolute alcohol although it is soluble i n tlilute alcohol t o a more or less extent. , T h u s i t would seem t h a t there are two substances present, both of which are of a resinous nature, a n d t h a t at least one of t h e m is largely t h e lead-precipitating material of t h e bean: a n d is also a part of t h e coloring matter. The chief function of t h e resins, however, is as fixative for t h e delicate flavoring compound a n d it is me11 known t h a t a n extract which contains b u t a sma1.l amount of these resins will not retain its value as
2
1
2 8
4 5
“Der Pflanzen chemie,” Vol. 1, p. 89. “Festschrift of O t t o Wallach,” 1909, 649. American Perfumer, Xov., 1908, 167. “Alois von Isakovics,” 1914, Minutes of t h e F. E. M . A Bey., 9 (1876); 1289.
July, 1916
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 C H E M I S T R Y
long as a n extract t h a t contains a larger a m o u n t of them. Their ability t o hold on t o t h e aromatic compound is great a n d was no doubt t h e cause of t h e long mistaken idea about their flavoring value. Alcohol a n d alkalies dissolve t h e resins readily, b u t t h e y are almost insoluble in all of t h e other solvents a n d entirely so i n water. When t h e alcopol is removed from a n alcoholic solution of t h e resins b y evaporation t h e resins are precipitated in a very fine s t a t e of subdivision a n d are light brown in color. On filtering a n d drying they darken a n d finally t u r n almost black. GRINDING VANILLA B E A N S
T h e r e a r e various acids present in t h e vanilla bean, such as oxalic a n d vanillic, b u t t h e y are of no flavoring value except when t h e y are present in t h e form of esters. It is, however, very likely t h a t these acids, which are of no value in a new extract, become very valuable when t h e extract has been aged, due t o t h e formation of esters. Before employing vegetable drugs i n t h e various pharmaceutical preparations, i t generally becomes necessary t o reduce t h e m t o a s t a t e of subdivision more or less fine, according t o t h e nature of t h e material. T h e moisture present in t h e beans makes their reduction very difficult a n d still it is imperative t h a t t h e y be reduced t o a rather fine state of subdivision in order t o obtain a uniform a n d sufficient extraction. It is t h e custom of some manufacturers t o reduce t h e beans t o a very fine s t a t e b y first cutting into small pieces a n d t h e n passing t h e m between steel rollers, which are set fairly close together. Others obtain a rather fine degree of subdivision b y grinding t h e beans in some suitable mill, as a sausage grinder for example, after t h e beans have been mixed with quite a large a m o u n t of fine white sand or granulated sugar. Still another method is t o cut t h e beans b y means of rapidly moving vertical knives until a suitable s t a t e of subdivision is obtained. Grinding or pounding t h e beans has a tendency t o press out t h e soft pulp, which soon retards t h e reduction of t h e tough fiber a n d requires t h e expenditure of much time a n d labor. In all processes in which grinding, pounding or rolling a r e used for t h e reduction of t h e beans, q u i t e a little heat is developed during t h e process a n d is doubtless detrimental because of loss of flavor b y volatilization. Comminution of t h e beans b y passing between steel rolls is very efficient, b u t objectionable on account of t h e great a m o u n t of heat developed. Much can be said in favor of this process a n d it is possible t h a t t h e objectionable heating of t h e beans could be overcome b y cooling t h e rollers with cold water circulating through t h e m . I t is claimed t h a t t h e process of cutting t h e beans, with t h e vertical knives, overcomes this heating difficulty a n d leaves t h e beans practically in their original condition, no pulp being expressed a n d a uniform product being obtained which is superior t o t h a t produced b y other methods. DRYING VANILLA BEANS
This difficulty of reducing vanilla beans t o a suitable s t a t e of subdivision is well known a n d one t h a t is
609
bound t o cause more or less trouble on account of t h e n a t u r e of t h e material. Vanilla beans contain moist u r e i n a n amount from I O t o 50 per cent a n d i t is desired t o extract from t h e m , not only t h e vanillin a n d other aromatic compounds, b u t also as much of t h e resins a n d other extractive matter as is possible a n d still hold t h e alcohol low enough in strength t o obtain maximum coloring matter. A very good extraction can be obtained with a j o t o 6 0 . per cent alcoholic menstruum, b u t still i t is not complete. T h e higher t h e alcoholic content of t h e menstruum, t h e greater is t h e extraction of t h e resins, b u t if t h e alcohol exceeds 65 per cent, t h e lower t h e amount of coloring matter which is extracted. When t h e beans have been dried, however, it is possible t o obtain a far better extraction of both t h e resins a n d t h e coloring matter a n d , a t t h e same time, overcome t h e difficulty of reducing t h e beans t o a fine s t a t e of subdivision. I n order t o determine t h e most desirable method of drying, a n d t h e effects produced on t h e beans, t h e following experiments were carried out on a good quality of Mexican beans which contained about 2 2 . 5 per cent of moisture. No. I-One hundred grams of chopped beans were placed in a glass tube, which was contained in an oven and heated a t 1 2 2 ' F. (50' C.) for eight hours. By means of an air pump a slow current of dried air was passed through the heated beans, the air being washed on leaving the tube by passing through dilute alcohol. The loss in weight amounted to about 2 0 per cent at the end of 8 hours, which was about go per cent of the total moisture present. When the alcohol, through which the air had passed, was carefully evaporated, only a trace of vanillin was found. No. 2-Experiment No. 2 was the same as No. I , except that the drying was done a t room temperature. The loss in weight in 8 hours was about I O per cent; in 2 0 hours, about 14 per cent, and in 48 hours, about 1 8 per cent, which was about 80 per cent of the total moisture present. The amount of vanillin removed here was about the same as in No. I . No. 3-One hundred grams of the same beans were spread out in a thin layer and exposed to the air a t room temperature. The loss in 2 4 hours was about 14per cent; in 48 hours, 18 per cent, or about 18 per cent of the total moisture present. No. 4-One hundred grams of the same beans were placed in a glass tube through which a strong current of air was blown, the whole being kept a t the room temperature. The loss in 8 hours was 2 0 per cent, or about 90 per cent of the total moisture present. As in experiments Nos. I and 2, the air was passed through washing towers which contained dilute alcohol and dilute potassium hydroxide solutions, respectively. The air current was under such pressure that it was impossible to completely wash it of volatile aromatic substances, since it still smelled strongly of vanilla even after it had passed through both solutions. The mixed solutions were then freed from alcohol, acidified and extracted with ether. On evaporating the ether, the residue remaining was dark brown in color, had a rather strong vanilla odor and contained a great number of well defined crystals of vanillin. The method of drying was as efficient as the one in which heat was used, but quite obviously, it would not be practical with a high-grade bean because of material loss of flavor. On t h e large scale, t h e drying a t room temperature can be easily affected b y spreading t h e chopped beans in thin layers on tables a n d turning t h e drafts from electrical fans over them. Or t h e beans could be
610
T H E JOL'RNAL OF I.VDCSTRIAL A Y D ELVGINEERING C H E M I S T R Y
placed on shelves in a sniall room through which a current of air is drawn. By this method t h e temperature could be regulated b y either heating the entire room or by allowing only heated air t o enter. An arrangement of the shelves in such a way t h a t only alternate ones extend clear t o the side walls! on each side! would force a more complete circulation of t h e air over t h e beans, since t h e air would have t o go over the entire length of t h e shelves in order t o descend. The beans dried in t h e above experiments were used, along with similar b u t undried beans, t o make several extracts in order t o see if t h e drying had in a n y way altered their value from a flavoring, as well as from a n analytical. standpoint. The dried beans were very brittle, which made it easy t o reduce them t o a fine powder. Their aroma seemed different from t h a t of the undried beans. being rather strong and harsh when compared with undried beans. The process of extraction consisted of a one week's maceration followed by a slow percolation. Complete extraction was naturally not obtained, owing t o t h e short duration of the process, b u t all of the extracts were made a t the time and under t h e same conditions and hence Extr. Percentages No. Alcohol Vanillin 12 50 0.23 13 50 0.23 14 50 0.23 SO 0.23 15 16 j0 0.23 17 50 0.23 18(b) 35 0.23 19 40 0.23 20 45 0.23 50 0.23 21 35 0.23 22 23 40 0.23 45 0.23 24 50 0.23 25 26(c) 60 0.22 40 0.20 27 28 40 0.26 29 40 0.26 30 40 0.26 31 40 0.21 0.16 32 40 33 jo 0.23 33.4 50 0.23 34 62 0.21 ( a ) Extract color.
1
I n the case of the "Lead S u m b e r , " ' however, tve \\-ere able t o obtain some variations in extracts from dried and undried beans but none of great importance. The greatest increase was from 0 . 6 3 2 4 ( Y o . 1 2 ) t o 0 . 809 j (No. 24) which is a n increase of 0 . 1 7 plus and was obtained from a dried bean extract. But such a great increaseowas not constant throughout the entire nuinber of extracts and could not be taken as typical. The lead numbers of t h e undried bean extracts varied from 0 . 6 3 2 4 (KO.1 2 ) t o 0 ,748 j ( S o . 2 1 ) ancl aveeaged 0 . 6 9 5 1 for t h e seven extracts. Those of t h e dried bean extracts varied from 0 . 7 1 3 8 ( S o . 2 5 ) t o 0 . 8 0 9 j ( S o . 2 4 ) a n d averaged 0 . 7741. This gives a n average increase of only 0 . 0 ; 9 $ a value T O O small t o be of a n y great importance. I n determining the lead numbers of this. the alkali and a part of t h e menstruum series, it was not possible t o obtain clear lead acetate filtrates and we had t o content ourselves m-ith rather cloudy solutions of t h e unused lead acetate. The lead precipitates in most of the cases were also unnatural, both in color and appearance. I t was necessary t o centrifuge most all of t h e samples in order t o obtain a solution t h a t would
T A B L EI-EXTRACTIOKEXPERIMEKTS (SERIES2) TOTALC O L O RRatio of Red KO. Red Yellow t o Yellow(a) BEAK ADDITION REMARKS 0.6324 22.5 75.0 1 : 3.3 Fresh .... 0.6379 1 5 . 0 52.5 1 : 3.5 Fresh Sand 0.7219 1 7 . 5 62.5 1 : 3.5 Fresh Sand T o sugar 0.7472 25.0 92.5 1 : 3.7 Dried .... ......... 0.8034 2 5 . 0 87.5 1 : 3.5 Dried Sand and Sugar . . . . . . . . . . 0.8011 2 5 . 0 87.5 1 : 3.5 Dried Sand, n o Sugar ......... 0.6905 1 7 . 5 50.0 1 : 2.8 Fresh , . . ......... 0.6955 1 7 . 5 22.0 1 : 3.1 Fresh .... . . . . . . ,s.O 1 : 3.0 Fresh .... . . . . . . . 0,7390 2 5 . 0 0,7485 2 5 . 0 77.5 1 : 3.1 Fresh .... . . . . . . . . 0.7560 22.5 i : 3.0 Dried , . . ......... 0.7581 2 5 . 0 ii.5 1 : 3.1 Dried , . .......... 0.2095 2 5 . 0 90.0 1 : 3.6 Dried .... .......... 0.t438 25.0 90.0 1 : 3.6 Dried .... .......... 1 : 3 6 ' Fresh .... .......... 0,442 22.0 117.0 0.433 25.0 50.0 1 : 2.0 Fresh .... .......... 0.552 30,O 100.0 1 : 3.3 Fresh Sand .......... 110.0 1:2.6 Sameas28 . . . . .......... 0,510 42.5 60.5 1 : 3.0 Fresh Sand Xacerated for 5 mo. 0.438 20.0 .... hfacerated 30 hrs. a t 110' F.(c) 0.415 25.0 90.0 1 : 3.6 Fresh 0.460 27.5 72.5 1 : 2.6 Dried . . . Macerated 15 hrs. a t 110' F. ... Macerated 3 mo. 7 5 % glycerin in menstruum 0.608 40.0 100.0 1 : 2.5 Fresh .... Same as 33 after 6 mo. 0.658 38.0 102.0 1 : 2.7 Fresh 110.0 1 : 4.4 Fresh Tahiti . , . . .......... 0.506 25.0 ( h ) Extracts 18 t o 26 contain 20 per cent sugar. (c) Extracts 26 to 33.4 were made from the same Mexican bean Lead
55.5
are comparable. In t h e case of t h e dried beans, a n allowance was made for the absence of t h e moisture in weighing out t h e samples. Menstrua of varying strengths mere also used on both dried and undried beans, and also t h e 1-alue of packing .the beans with sand and sugar, both independently and together. was studied. T h e analytical results obtained from these extracts are given in Table I , extracts Nos. 1 2 t o 2 5 , inclusive. T h e percentage of vanillin remained the same in the entire number of extracts. in this experiment, regardless of t h e variations in t h e method of extraction or t h e use of dried beans. The extraction of vanillin seems t o be fairly simple, even with a low percentage of alcohol, b u t it is not complete and t h e dregs still contained some undissolved. T h a t part of t h e vanillin which was not removed b y t h e menstruum was doubtless contained in t h e beans in such a way t h a t t h e menstruum could not get in contact with it, for neither drying nor grinding increased t h e amount of vanillin in the extract.l T h e vanillin was estimated b y t h e Folin colorimetric method, T H I S 4 (1912), 670
JOCRNAL,
1-01,X NO.7
ZSTRACT Clear Clear Clear Clear Clear Clear Cloudyfh) Cloudy Clear Clear Cloudy Clear Clear Clear Clear Cloudy Clear Clear Clear Clear Clear Clear Clear (:!ear
filter a t all and some stood this action for a n hour without producing a solut,ion t h a t would filter clear. This cloudiness of t h e lead acetate filtrates made the exact determination of t h e unused lead a little troublesome and in some cases almost impossible, a n d , no doubt, accounts for the variations obtained from very similar extracts ( N o . 24 and S o . 2 5 , for instance)! b u t the determinations were all made in duplicate, the average being taken as t h e true value. and in most cases t h e duplicates were very close. On the Ivhole, t h e values obtained were certainly near enough for all practical purposes, notwithstanding the trouble encountered in obtaining them. The "Total Color"2 of t h e extracts n-as t h e most varied constant of all and is the best guide far the degree of extraction. Unlike the vanillin and lead n u m ber, the color values are greatly influenced b y the amount of alcohol in t h e menstruum, inkreasin:: as the alcohol approaches 6 j per cept, a n d falling OH as the alcohol exceeds 65 and approaches 95 per cent. The undried bean extracts gave values for red vary1
2
U. S. Dept. Agr., Bureau of Chem., E d ? . 132, 110: I h i d . , 137, 120. I b i d . , 1 5 2 , 148.
July, 1916
T H E J O U R N A L 0 F I N D U S T RI A L A N D E N GI N E E RI N G C H E MIS T R Y
ing from I j (No. 13) t o 2 5 ( N o . 2 1 ) and for yellow, from 50 ( N o . 18) t o 7 7 . j ( N o . 2 1 ) . The dried bean extracts gave values for red from 2 2 . j (No. 2 2 ) t o 2 5 (No. 2 3 , etc.) a n d for yellow, from 6 7 . j (No. 2 2 ) t o 9 2 . 5 (KO. IS). Thus it is easily seen t h a t a dried bean will give u p more of its color t o a given amount of alcohol t h a n will a n undrled bean, especially in regard t o t h e yellow. The color is t h e most difficultly extractable p a r t of the bean a n d is of commercial value but t h e drying of t h e beans does not make such a great amount of difference, a t least, hardly enough t o justify t h e drying of t h e beans for t h a t purpose alone. I t might be added here t h a t i t was impossible t o obtain t h e lead filtrate color values, as is t h e custom, on account of t h e cloudy filtrates mentioned above. The ratio of red t o yellow, in t h e tables, is of little value in a n analysis so long as it passes t h e requirement of not being less t h a n I : 2 . 2 , a n d in our work means very little or nothing.’ T h e flavor of these extracts, made from t h e undried and dried beans, seemed t o be about equal where the same amount of alcohol had been used. The period
ANALYTICAL R E S U L T S
OBTAINED
DRIED AND
FROM VANILLA UNDRIED
EXTRACTS MADE P R O M
BEANS
of maceration, however, was so short t h a t t h e maximum flavor was not obtained a n d it was very difficult t o detect a n y difference between them. I t seemed possible t h a t t h e undried bean extracts were a little more aromatic t h a n t h e dried bean extracts b u t t h e difference. if any, was certainly small. I n order t o be certain about this; we prepared two extracts from the same beans, both dried a n d undried, b y packing with sand and macerating for two months before percolation. The menstruum contained 50 per cent alcohol and the maceration was carried out at room temperature in glass percolators. These extracts had a fine delioate aroma and it seemed certain t h a t t h e one made from t h e dried beans was superior t o t h e undried bean extract. The flavor of t h e dried bean extract was clearly more pronounced a n d seemed on t h e whole t o be better. It is certain t h a t t h e flavor of t h e dried bean extract was not inferior t o t h e undried bean extract 1 This constant is determined by comparing the color of the extract, after suitable dilution, with standard colored glass slides. T h e numbers under red a n d yellow in the tables den6te the amount of standard red and yellow estimated t o be present in the total color complex of the extracts. These values are determined in a Lovibond tintometer, a n d are entirely empirical in nature, being of service only as a means of comparison.
611
This result leads t o t h e conclusion t h a t drying vanilla beans is of service where i t is done at room temperat u r e a n d with a slow current of air. T h e differences obtained in t h e lead numbers, color values, clarity a n d flavor, were not exceedingly great b u t when summed u p t h e y make quite a contrast between the two extracts, everything being in favor of t h e dried beans. DEFINITE UOISTURE CONTENT
As has been stated before, vanilla beans contain various amounts of moisture and it is generally t h e rule t h a t t h e most prized beans contain t h e most moisture. This moisture is t h a t left in t h e beans in t h e curing process a n d is certain t o cause more or less reduction of t h e alcoholic strength of the menstruum used t o extract them, which naturally reduces the extractive power of t h e menstruum. Drying t h e beans a t a low temperature and with a slow current of air has been found t o be a good means of overcoming t h e influence of this moisture b u t drying may not be always desirable or possible a n d some other means would have t o be resorted t o in order t o obtain t h e same result. This is best done b y regulating t h e amount of alcohol in t h e menstruum t o suit the amount of moisture in t h e beans and will accomplish about t h e same result as the drying. The idea here is t h a t the moisture of the beans amounts t o just t h a t much water, and enough absolute alcohol must be added t o convert this water into a hydro-alcoholic mixture of the same alcoholic strength as t h a t of t h e menstruum. Thus, if I O O lbs. of beans are t o be worked u p which contain 2 j per cent moisture. there is added with the beans some 3 gallons of water in excess t o t h a t allowed for in the formula a n d , if a 50 per cent menstruum is being used, 3 gallons of 9j per cent or absolute alcohol ought t o be added t o convert the moisture into a j o per cent hydro-alcoholic mixture. Some manufacturers make use of a 60 or 6 j per cent alcoholic menstruum t o extract t h e beans a n d t h e n reduce t h e alcoholic strength of the otherwise finished extract t o 4 0 or 4 j per cent by the addition of water. This method ought t o prove of service, not only in producing a more complete extraction and a more uniform product, b u t also in being able t o make use of t h e higher strength alcohol for the extraction and still finishing t h e extract a t a comparatively low alcoholic content. This method is based on the well known fact t h a t once a substance, especially organic extractive matter, is in solution in alcohol it is possible t o reduce the strength of the alcohol considerably without precipitating th8 dissolved substance. In using such a method, however. it is necessary t o avoid too great a reduction of the alcohol for this would produce too great a concentration of the dissolved material and a separation would in time take place. I n making such a reduction of t h e alcoholic strength, of t h e otherwise finished extract, it is desirable t o know t h e amount of alcohol present so as t o avoid too great a reduction in order t o avoid a n y future separation. A reduction from 60 t o 40 per cent will produce a separation in t h e course of a year, especially if t h e extract has been cooled t o a low temperature. A much smaller reduction ought t o prove of more service even if
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 C H E M I S T R Y
612
i t is necessary t o make t h e extraction with a lower percentage of alcohol, s a y 5 0 or j 5 per cent and then reducing t o 40 or 45 per cent. I t is obviously necessary t o make a stronger t h a n I O per cent extract when such a method is employed so t h a t the finished product will represent t h e soluble matter from I O grams of beans in J O O cc. of t h e extract. I t is also of great importance t o have the water added very slowly and under constant agitation in order t o prevent a cloudy product, which is certain t o form if the water is added quickly. We made some experiments along this line t h a t seem very conclusive. The beans were extracted first with 9 j per cent or straight alcohol and the percolates thus obtained were diluted Kith a n equal volume of water. I n half of t h e samples t h e water was added a!l a t once and in the others t h e water was added very dow'ly and with frequent agitation. All of these percolates were then poured back into their respective percolators and, after a week's maceration, mere repercolated. I n every case where t h e water was added quickly we obtained a cloudy extract; and in every case where t h e water was added slowly me obtained BEAN
M. 41.
J. P. T.
Per cent Moisture 35
22.5
Extr.
No.
40 41 42 43 44 45 46 47 48 49 50 51 52 53
KO. 0.613 0.597 0.592 0.625 0.613 0.572 0.613 0,833 0.796 0.773 0.726 0.724 0,700 0.700 0.950 0.871 0.855 0.830 0,892 0.822 0.814 0.648 0.651 0.662 0.640 0.616
'
0,612
0,599
Red Yellow 15.0 15.0 3u.u 47.5 15.0 50.0 16.0 12.0 50.0 16.0 57.0 16.0 56.0 17.0 50.0 16.0 54.0 16.0 56.0 20.0 69.0 72.0 18.0 68.0 19.0 6 8.0 19.0 83.0 31.0 95.0 44.0 94.0 36.0 94.0 44.0 4 9 . 0 106.0 4 6 . 0 112.0 4 5 . 0 112.5 73.0 26.0 24.0 73.0 82.0 25.0 25.0 83.0 75.0 24.0 94.0 27.0 27.0 95.0
a clear extract. The total color and lead numbers of all of these extracts were about t h e same b u t t h e clarity of the products was very different, showing . t h e effects of t h e two methods of dilution. T h e moisture of t h e beans can be easily determined on small samples b y direct drying a t 100' C. (212' F.) and then weighing. Or t h e determinations can be made on a larger sample by distillation in petroleum oil and calculating from the amount of water in t h e distill a t e. E F F E C T S O F VARYING AJIOUXTS OF ALCOHOL
I t has been shown t h a t extracts ,made from a dried bean will give constants t h a t vary more or less from extracts made from t h e same b u t undried beans and, also, t h a t almost t h e same result can be obtained from a n undried bean if t h e alcoholic strength of t h e menstruum is altered t o suit t h e moisture content of t h e bean. There remains, however, a little more t o be said in regard t o t h e constants obtained from t h e same beans with varying amounts of alcohol. 1
U,S. Dept. of Agt'., Bur. of Plant Ind., Bull. 99, and Circ. 73.
a, No. 7
We prepared eight extracts, four from dried a n d four from undried beans, using alcoholic menstrua varying from 35 t o 50 per cent (Table I , extracts No. 18 t o No. 2 5 inclusive). T h e beans were the same as used in all of the other experiments. T h e C. F. Sauer Co. also prepared twenty-eight extracts for us which were made from four varieties of beans and with menstrua varying from 30 t o 62 per cent alcohol (Table 11, extracts from No. 40 t o No. 67). T h e object of this experiment was t o see if t h e different amounts of alcohol would make a difference in t h e analytical constahts of the finished extracts. By reference t o Table I it will be seen t h a t the vanillin remained t h e same in all of t h e eight extracts which we prepared regardless of the amount of alcohol in the menstruum. In t h e lot of twenty-eight extracts, Table 11, the percentage of vanillin varied slightly in t h e four different series of extracts b u t t h e variations were not great enough t o be of a n y importance. I n fact it was found quite generally t h a t the vanillin remained constant, or nearly so, in every series of experiments where the same bean was used
TABLE II-IVIENSTRWUMEXPERIMEXTS(WITHOUT SUGAR) Lead EXTRACT COLORFILTRATE COLORRATIO RED TO
PERCEKTAGES Alcohol Vanillin 30 0.23 35 0.23 40 0.22 45 0.23 50 0.23 62 0.22 57 0.21 30 0.21 35 0.21 40 0.21 45 0.22 50 0.21 0.21 62 57 0.21
Vol.
R e d Yellow
...
. ... .,.
.,,
...
..
..n
,
5.0 5.0 4.4
1.0 1.0 1.0
... . . . ... ...
... ... ...
...
5.0 5.0
1.0 1.0 1 .o
5.0 .
... ... ...
2.0 2.4 2.4
.,. .., i
.
.
...
2.0 1.0 1.4
.
1
. . I
"..
...
'
7.8 10.0 10.0
. ~ . ... ... , . .
7.8 4.5 5 ,6
Extract 1:3.0 1:3.3 l:3,1 1 : 3.1 1 : 4.0 1 : 3.8 1 : 3.7 2.8 3.4 3.4 3.4 3.8 3.6 3.6 2.7 2.15 2.6 2.15 2.16 2.4 2.5 2.8 3.1 3.3 3.3 3.1 3.4 3.4
YELLOW
Filtrate
..., .... ....
1':' 5 : O 1 : 5.0 1 : 4.4
. ... ... .
....
1':' 5:o 1 : 5.0 1 : 5.0
... .. ~. .. t . .
,
...
1 : 3.9 1 : 4.1 1 : 4.1
....
.... ..., , . . I
1 : 3.9 1 : 4.5 1 : 4.0
REMARKSOCondition N EXTRACT Color Light Slightly turbid Light Slightly turbid Light Slightly turbid Light Slightly turbid Light Clear. Precipitate Light Clear Light Clear Light Clear Light Slightly turbid Light Slightly turbid Light Clear Light Clear. Precipitate Light Clear Light Clear Dark Dark Dark Dark Clear Dark . Clear. Precipitate Dark Clear Dark Clear Dark Very turbid Dark Cleat' Dark Slightly turbid Clear Dark Clear Dark Dark Clear Clear Dark
regardless of all modifications in t h e method of extraction. The lead numbers of t h e eight extract9 in Table I were almost, b u t not quite, constant. There were some variations but they were not of a definite nature, neither increasing nor decreasing regularly with t h e variations in t h e alcoholic content of t h e menstrua. I n t h e lot of extracts recorded in Table I1 we noted a slight decrease in the lead numbers with a n increase of t h e alcohol in the menstrua, except in the case of the AI. M. bean extracts where t h e values remained almost constant. This decrease in the lead numbers was small and not large enough t o be of any commercial importance, from a n analytical standpoint, b u t still it was large enough t o be measured and t o be noticeable in the table of results. The smallest variation was in the h I . II.bean samples and was from 0.62j t o 0 . 5 7 2 , the whole series averaging 0.602. The J. P. T. bean extracts' varied from 0.833 t o 0 . 7 0 0 and averaged 0 . 736, The. Mexican cuts gave extracts t h a t varied from 0 . 9 j o t o 0 . 8 1 4 and averaged 0.862.
July. 1916
T H E J O U R N A L OF I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y
T h e Bourbon bean extracts varied from 0.662 t o o . 599 a n d averaged 0.632. T h e smallest variation i n a n y one series was 0.053 a n d t h e largest variation in a n y one series was 0.136. T h e t o t a l color of t h e extracts was increased, u p t o a maximum amount. with a n increase of alcohol in t h e menstruum . This was t r u e in all b u t a very few exceptions. a n d those were minor ones. t h e differences being small. All t h a t has been said before i n regard t o t h e general nature of t h e color of t h e extracts applies here as well . I n some of t h e samples we were able t o obtain t h e lead acetate filtrate color values b u t t h e y are of little importance . I n t h e extracts made from t h e Mexican cuts t h e ratio of red t o yellow. in some cases. was below t h e Federal requirement of being not less t h a n I : 2.2. Three of these extracts gave ratios of I : 2 . I 5 . showing a n excessive a m o u n t of red in t h e color complex . This is doubtless due t o t h e n a t u r e of t h e beans. produced b y t h e curing process. a n d not t o t h e presence of caramel in t h e beans. as has been sometimes claimed. for we were not able t o detect t h e presence of caramel in either t h e beans or t h e extracts . As has been said before. t h e primary object of this experiment was t o see what t h e effects would be on t h e vanillin content. t h e lead number a n d t h e total color of t h e extracts made from t h e same beans with varying amounts of alcohol . F r o m t h e whole number of extracts i t seems certain t h a t t h e vanillin content is altered only very slightly. if a t all; t h a t t h e lead number is decreased t o a small degree a n d t h a t t h e total color a n d clarity of t h e extract is increased up t o a maximum b y a n increase of alcohol in t h e menstruum. u p t o about 6 j per cent . T h e flavoring value of t h e extracts made with t h e various amounts of alcohol were about t h e same where t h e extracts were prepared in a short time b u t in t h e samples which were macerated for two months before percolation. i t was easily seen t h a t t h e extract prepared with t h e 60 per cent menstruum was superior t o t h a t made with t h e 5 0 per cent mens t r u u m . T h e color of t h e 60 per cent extract was darker t h a n t h e 5 0 per cent extract a n d t h e extract showed a less tendency t o precipitate when i t was subjected t o a low temperature . There does not seem t o be much uniformity in opinion among manufacturers a s t o t h e most desirable amount of alcohol t o be used in making vanilla extract b u t from our experiments it seems certain t h a t 60 per cent alcohol produces a much finer extract t h a n can be obtained with 5 0 per cent alcohol . T h e 60 per cent alcohol extract h a d a more delicate flavor. was stronger a n d h a d a darker color t h a n t h e 5 0 per cent extract . T h e lead number. however. was slightly reduced b y t h e use of t h e higher a m o u n t of alcohol . USE O F A N A L K A L I
I t is well known t h a t a complete extraction of vanilla beans with alcoholic menstrua is not possible a n d t h a t t h e dregs left after percolation always contain more or less valuable material . Only a p a r t of t h e resin is soluble in dilute alcohol a n d t h e same is true with 95 per cent alcohol . KO matter what strength
613
alcohol is used for t h e extraction. a p a r t of t h e extractive m a t t e r is lost. due t o its insolubility . These constituents are. however. soluble i n alkalies a n d therefore in alkaline menstruum will remove a far greater a m o u n t of t h e m t h a n will a neutral or acid menstruum . A t first thought it might appear t h a t t h e use of a n alkali i n a n extract of vanilla is a n adulterant . It is. however. o n theoretical grounds t h e logical thing t o do. because of t h e acid n a t u r e of vanilla beans T h e use of acids a n d alkalies i n alcoholic menstrua for t h e extraction of vegetable drugs has found practical application in a number of cases a n d makes possible some pharmaceutical preparations t h a t would be unsatisfactory without t h e m . A well known example of t h e use of a n acid is in fluid extract of blood Extr .
TABLE111-ALKALI EXPERIMENTS (SERIES 1) Per cent Lead TOTAL COLOR Ratio Red
Per cent . KlCOa 1A . . . . . . . . . . 0.00 B .......... 0 . 0 0 c . . . . . . . . . . 0.00 D . . . . . . . . . . 0.00 Av . . . . . . . . . . . . . . . 2A . . . . . . . . . . 0.04 B .......... 0 . 0 4 C .......... 0 . 0 4 D .......... 0104
NO
Av . . . . . . . . . . . . . . .
3A . . . . . . . . . . 0 . 0 8 B 0.08 C . . . . . . . . . . 0.08 D . . . . . . . . . . 0.08 Av . . . . . . . . . . . . . . 4A . . . . . . . . . . 0.12 B . . . . . . . . . . 0.12 c . . . . . . . . . . 0.12 D . . . . . . . . . . 0.12 Av . . . . . . . . . . . . . . . 5A . . . . . . . . . . 0 . 1 6 B . . . . . . . . . .0 . 1 6 C . . . . . . . . . .0.16 D . . . . . . . . . . 0.16 Av . . . . . . . . . . . . . . . 6A . . . . . . . . . . 0.20 B .......... 0.29 . . . . . . . . . . 0.20 D . . . . . . . . . . 0.20 Av . . . . . . . . . . . . . 7A . . . . . . . . . . 0.24 B 0.24 C 0.24 D .......... 0.24 Av . . . . . . . . . . . . . . . 8A 0.28 B 0.28 C . . . . . . . . . . 0.28 D 0.28 Av 9A 0.32 B . . . . . . . . . . 0.32 Av 10A . . . . . . . . . . 0 . 3 6 B 0.36 Av 11A 0.40 B . . . . . . . . . . 0.40 Av . . . . . . . . . . . . . . .
..........
c
.......... ..........
.. .. .. .. .. .. .. .. .. .. .......... ............... ..........
. ............. ..........
............... ..........
Vanillin 0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.22' 0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.22
NO
.
0.5969 0.5286 0.5682 0.5669 0.5651 0.7144 0.6571 0.7226 0.6311 0.6813 0.6474 0.7506 0.7267 0. 6693 0.6985 0.7540 0.7923 0.6830 0.6789 0.7320 0 7855 0.7554 0.7363 0.7691 0.7615 0.7089 0.7895 0.8360 0.8073 0.7854 0.8018 0.6325 0 . 7472 0.7554 0.7342 0.7786 0.7977 0.8674 0.8264 0.8175 0.8073 0.7991 0.8032 0.8360 0.8169 0.8264 1 . 015 0.9794 0.9972
Red 25.0 15.0 27.5 25.0 23.1 20.0 20.0 25.0 25.0 22.5 25.0 25.0 25.0 27.5 25.6 25.0 25.0 27.5 30.0 26.9 27.5 27.5 27.5 32.5 29.4 30.0 27.5 37.5 37.5 33.1 27.5 30.0 40.0 47.5 36.2 32.5 37.5 45.0 47.5 40.6 40.0 42.5 41.2 37.5 42.5 40.0 37.5 40.0 38.7
Yellow 77.5 52.5 87.5 87.5 76.2 75.0 75.0 82.5 80.0 78.1 72.5 75.0 85.0 87.5 80.0 77.5 80.5 77.5 85.0 80.0 77.5 82.5 90.0 92.5 85.6 77.5 82.5 97.5 100.0 89.4 80.0 82.5 125.0 120.0 102.0 80.0 87.5 117.5 122.5 102.0 87.5 92.5 90.0 92.5 95.0 93.7 95.0 97.5 96.2
to YelIow 1 : 3.1 I : 3.5 1 : 3.1 1 : 3.5 1 : 3.3 1 : 3.7 1 : 3.7 1 : 3.3 1 : 3.2 1 : 3.4 1 : 2.9 1 : 3.0 1 : 3.4 1 : 3.1 1 : 3.1 1 : 3.1 1 : 3.2 1 : 3.1 1 : 2.8 1 : 3.0 1 : 2.8 1 : 3.0 1 : 3.0 1 : 2.8 1 : 2.9 1 : 2.6 1 : 3.0 1 : 2.6 1 : 2.6 1 : 2.7 1 : 2.9 1 : 2.7 1 : 3.1 1 : 2.5 1 : 2.8 1 : 2.1 1 : 2.3 1 : 2.6 1 : 2.3 1 : 2.5 1 : 2.2 1 : 2.2 1 : 2.2 1 : 2.4 1 : 2.2 1 : 2.3 1 : 2.5 1 : 2.5 1 : 2.5
root where t h e acid is necessary to'dissolve t h e alkaloids. and. of t h e use of a n alkali. in fluid extract of senega where t h e alkali is used t o dissolve t h e pectins . T h e use of a n alkaline menstruum has also found some application in t h e preparation of vanilla extract a n d it should produce a n extract t h a t is higher in both color a n d lead number values t h a n could be produced from t h e same beans with a neutral mens t r u u m . T h e question at once arises: Will t h e alkali modify t h e flavor or will i t intensify t h e flavor? It was for t h e purpose of answering these questions t h a t some 34 extracts containing various amounts of potassium carbonate were prepared . T h e y were made i n t e n different lots containing- t h e alkali in amounts varying from 2 5 grains (0.04 per cent) t o 2 5 0 grains ( 0 . 4 per cent) t o t h e gallon . A t t h e same time we
T H E JOL’RA-AL O F I ; l T D C S T R I A L A Y D ELVGIAVEERI,YG C H E M I S T R Y
614
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.
