1302
INDUSTRIAL AND ENGINEERING CHEMISTRY
VOl. 20, KO. 12
Relation of Chemistry to the Citrus Products Industry C. P. Wilson RESEARCH DEPARTMENT,
T
CALIFORNIA
FRUITGROWERS EXCHANGE,
ONTARIO, CALIF.
H E need for the higher t h a n t h a t of oranges. These wide development of the citrus prodvariations would be deucts industry in Calimoralizing to a manufornia is found in the facturer who did not economic fact that 100 recognize a fluctuating per cent of the citrus supply of per ish a b l e crop cannot be packed raw material as one of and shipped to market the uncontrollable facover a period of years tors in his operations. Probably no type of and sold for enough t o cover the cost of proorganization except a duction. This problem p u r el y non-profit coof handling s u r p l u s operative one can operagricultural crops in a ate successfully on such way that will not intera basis. fere with the orderly As t h e production marketing of the main and sale of citrus prodcrop a t a price that ucts has become more Panoramic View of The Exchange Orange Products Co., Ontario, Calif. firmly established the more than covers production cost was heavamount of fruit availily stressed by the president of the Anierican Institute of able for Such production has become more regular, thus inCooperation a t Berkeley in July, 1928. It was to take care suring a continuous supply of the products themselves. On of such surplus crops that the Exchange Lemon Products the average, probably 40 000 tons or more of oranges, lemons, Company was organized in February, 1915. the research labo- and grapefruit combined are available annually in California ratory of the Exchange in April, 1920, and The Exchange for conversion. The supply of oranges and grapefruit is rapidly increasing, though further increase in lemon production Orange Products Company in October, 1920. Such literature as might serve was drawn upon, but, except is not in sight. The task of the chemist is to develop new products and for an outline of methods for the production of citric acid and descriptions of the hand processes for the manufacture of processes for the better utilization of this surplus fruit, to lemon and orange oils, little information was available. The supervise and control the manufacture of such products and development in California has been for the most part pioneer t o develop outlets for them. A very important function is to sell chemistry to 11,000 grower owners of the products work. The California Fruit Growers Exchange is the marketing companies and keep it sold. agency for about 11,000 cooperating growers, who produce The Italian Industry 75 per cent of the oranges and over 90 per cent of the lemons grown in California. The Exchange Lemon Products ComThe manufacture of citrus products had its birth in Italy, pany is a voluntary cooperative organization of Exchange lemon shippers, the object of which is to convert surplus a t the time of the American Revolution. Up to a few years lemons into stable salable products. The Exchange Orange ago Italy produced 0111scitrate of lime, citrus oils, and some Products company performs a similar service for Exchange peel in brine from citrus fruits, the work being done in many small factories. The production of citric acid is now highly orange shippers. These products companies receive surplus fruit from their centralized in a few factories and exports of citrate of lime been much reduced. During the past year 'Iontemembers, process it, sell the products, and return whatever is left, after deducting all expenses, to the cobperating members. catinid*'*the dominant factor in the heavy chemical industry in Italy, has taken over the Arenella plant a t Palermo, which No dividends are paid on capital. KOprofit is made. The Exchange ships Over 40,000 carloads (400 boxes of is said to be under complete Italian control and is claimed t o about 75 pounds each) of oranges and Over 12,000 cars of be one of the largest and most modern citric acid factories in lemons annually. Thus a carload consists of 15 tons of fruit, the world. Some fairly satisfactory machines are being 'Or the production lemon (Beginning Kovember I , 1928, the standard carload of oranges The Italian journals shorn that citrus products are receiving is to be figured as 462 boxes, and lemons as 348 boxes, these a great deal of attention from able chemists and engineers and being the numbers usually packed in a car.) we are seeing andwillcontinue to see rapid and decidedprogress The quantity of fruit available for conversion into products in the technical as well as the administrative phases of the varies enormously. Receipts of lemons in a single season (November 1 t o October 31) have been as low as 1000 and as Italian citrus products industry. The Italian Government high as 78,000 tons. Monthly receipts have varied from none maintains the Royal Experimental Station for the Essential to nearly 15,000 tons. Receipts of oranges are more regular, Oil and Citrus Derivative Industry a t Reggio di Calabria, the work of that station being published bimonthly in the Bolbut they have varied from none to 3100 tons a month and from 5000 to 18,000 tons a year. The proportion of the lemon lettino ufficiale. * Numbers in text refer t o the bibliography at end of article. crop available for conversion into products is usually much
December, 1928
IHDUSTRIAL A X D ENGINEERING CHEMISTRY
An excellent review of the Italian situation has recently been given by Smith.2G The California Industry
The early efforts to establish the citrus products industry in California have been thoroughly presented by Will." Kunierous papers have been published on different phases of the development of cit.rus products.S~'~~'"J?"".L1As each of these papers covers the work on the citrus products witlr which i t deals a full review is superfluous. A word as to eacli class of products now beiirg produced or developed may be of interest,. Citric Acid
1303
the oil is made in contact with the juice, as in 6ome of the machine processes, however, this loss of citral may be partly OT fully compensated for by tlie unidentified flaTroring substances which the oil extractsfromthe juice. These substances contribute a flavor inore delicate, if less powerful and pungent, than the c i t d Both tlie machine-pressed and distilled oils are finding distinct favor in the oil trade for certain uses. Unfoilunately, acids react with citral quite readily in the presence of vater t o forin cymcnc, the substance that gives to leiiion oil an objectionable limy odor and taste. It is vitally important that citrus oils be stored in an absolutely dry condition if good aroma and flavor are t o be retained. Careful attention mist be paid to metallic containers, copper being especially detrimental and tin probably the most sat,isfactorq. Careful control of qiiality has eailseil C.aliforiiia oils to occupy 511 important prlaee iii tlic wxld supply.
The first citrus product firmly est.ablis1red i n California was ,citric acid, wliich has Ireen prodooed intermittently since about, 1893 and continuously since 1916. A citric acid Sactory Juice Products witlrout close chcrnical supervisioii \wuld soon cease to exist in t.lie highly competitive field that it sliares with the other "I 1;irge niimher of VCTS ;ihle chcniists arid lrncteriologists citric acid factories, as well as with those producing tnrtaric: have worked on the preservation of or;iiige and leinon juice iii malic, lactic, rind other edible acids. E'TOlii tlie test of the lemons for acidit.y to t,hc clicck oii t.lie piirit,y of tlie finisbed its iiatiirnl stat,e. McDermott's aorh oil Florida orangc product, tire inaliufacture of citric acid is a perfect example of juice*z showed the possibilities of preliaring pasteurized juice. the cont~olledproduction of an extremely pure ehrniieal from ICxcellent prodnrts liavc Been m:iiie wlicre tlie most sanitary tin agricultural raw msterial. Clieinistry plays its part not inemires were oiiserved, iiictallic cootnminatioii xas cliniionly in checking proce teps for efficiency, but in checking ii:itcd, and air was promptly a,nd pcriiranently excluded. coiitsniiriation of product and life of the cquipmeut arid in Such procedure iiccessitates V ~ T Yproiiipt handling anti does finding and trsting better equipment, and rnctliods. The not allo\r for the proper blending of juice Srorn diffcrcntlots of coinrnercial production of citric acid has Iieeii dcscrihed in Sriiit. As t,hc acidity OS Califorriia orarrgc juice varies from 0.i t,o 1.3 per ceiit or ereii inore, tlie total dissolved solidsfroiri detail.**,j' less than 10 per rent t,o more tlim 17 per eenl, and tlie ratio A favorite subject for citric acid chemists is the possibility (if solids to i~nhylrouscitric acid From 8 (minimuin legal ma(if direct crystallizat.ion of citric acid without going t,hTollgll the intermediate product, ealcirim citraie. I'oore"' has pro- turity) to ahniit 15, ixcasionrilly 17, i n niirrnal matiirc orange duced citric acid cTySt.ilk directly froin highly purified lemon juice, it is readily sceii that stnrid:iniiz:itiorr is iniporti~ntatid juice arid Ajon','hss elaborated it method for doing this. No also extrerncly difiicult. It lids been shown t;hat, changes i n commercial production has resulted, however, : i d the classical Sclieele rnetiiod of precipitating citric ticid as calcium citrate and dccomposiiig the citrate vith suliuric acid is still the cciit,ral Sea.ture of citric acid ]~roduct,ion. It is che;q~ert o remove citric acid with calciurri tlim t o remove a large numbcr of other tlririgs with several re:igetits a i d processes. This is true whether the citric acid be derimd from citrus fruits or pineapple juice OT is a product of fcrmontation processes. Essential Oils
The production of orange and lemon oils is, strictly speaking, a physical process, wlietlier t.lic spoiige m e t l ~ o d n, ~ ~ ~ ~ machine-pressing method, or distillation he used. The sponge method as used in Sicily since 1 i i G OT earlier is being partly replaced by mechanical processes. Distillation also has given very useful oils. Citrus Pulp Drier The part of the chemist is in the protection of oils from contamination and degradation, in the amalysis of tlie oils to orange juice after removal from the fruit tire of at least three determine compliance with food laws or pharmacopcias and kinds: (a)those duc to living organisms, easily prevented in tlie development of foriiiulns for their use. The real valua- by pasteurization. (The juice nf soririd oranges and lemons tioil of the oils is still largely an art based on a delicate seiise of has invariably beeii found to be sterile In situ. Contaminiismell rather tlian on analytical methods. However, much tioil t.akes pliice :LS soon as the juice is rcnioved except iiiidcr attention lias been pti.id to the determination of citral in a.scptic or nutiseptic conditions.); ( b ) tlrose due t,o eiizynies, lemon oil, as i t is a very important coirst,itiient and must be partly controlled by pasteurimtion but not. yet fiilly elucipresent to the extent of a t least 4 per cent in U. 8. 1'. oil. dxt.cd; ( c ) those due t o oxidation :md to clienricnl reactiorrs Many methods for the deteriiiinntion of citral have been between normal constituents of the juice, as, for instance, developed.'2J0 The Klebcr rnctlmJ, doponding on the rest- Mai1I:ird's" reaction between arnirio acids nrid suyars, caration between citral and plien~~lligdraziiic, is probably the most inelization, etc. The changes in the g r ~ i i pare aceclcrirted by lrcat and generally used and is the offiein1 U. S. 1'. iiietliod. Any lemon oil made by a process wliich briiigs t,he oil iri contact proceed a i t l r the form n of dark pigments. In some eases with a large volume of water or lenion juice loses Some carbon dioxide is evolved iii considerable qii:iiit,ity, though tlic citral due to its solubility in water and is almost in- juice is absolutely sterile. These reactions are also accelervariably below the 4 per cent U. S. 1'. standard. Where ated by roucentmtion. There are other ehnnges of a eheinieai
1304
INDUSTRIAL Ah’D ENGINEERIhrG CHEMISTRY
nature which have not been fully worked out, but there is reason to believe that one or more glucosides play a n important part in the darkening and flavor changes of citrus juices. It must be remembered that an orange is a living thing and life processes cannot be completely stopped without change in the character of the organism, whether it be a single cell or an extremely complex heterogeneous organism, such as an orange.
Val. 20, No. 12
with other similar lines. The world demand for candied orange and lemon peel would consuine but a few carloads of citrus fruit and would require a i least twice as much sugar as fruit. Of greater interest is the fact that orange and lemon peel have been shown to have a real vduc as a food for stock, principally for their carbohydrate content and in some degree for t.heir protein. Mead and Guilbert’* studied the digestibility of dried orange pulp, which remained from the production of orange oil and juice and dried lemon pulp” resulting from the production of citric acid and lemon oil. Sheep were the experiinent.al animals. Table I taken from Bulletin 439 of t,he University of California Experiment Station” gives the resrrlts. It is seen that both orange and lerrron pulp have a high content of digestible nutrients, being exceeded only by barley among the nine feeds for which data are included. Thus the value of orange and lemon pulp as feed for sheep was established. The actual use of several thousand tons of the fresh pulp by dairies has proved the value of that pulp as feed for dairy cattle. Feeding tests by tile Universidy of California have shown dried orange pulp to he equal to any other feed as a butterht producw. Tahle I-Ul~esfible Nufrienfs Contained in Variou8 C o m m o n Feoda f:omparcd_wilh Dried Pineapple Pulp Dried Orange Pulp. Dried Lemon Pulp, and U d OLive Pulp
Common hnileyi Dried orange pulp
Monel Metal Vacuum Pan for Concenrrerinyt oranfie Juice
mid lemon puip
Dried beet pulpb Dried pinenppie pulp Alfalfa hay, ell analyrrs1. Wheat strawh Dried olive pulp Raisin pulp
90.7 87.5
92,B 91.8 83.6
91 .1 91.6
Hesperidin has been positively identified (FIdI) in oranges. 11?.0 88.7 and other glucosides are associated with it. Contrrtry to texta Tote1 includes tat times fhe iactor 2.23. book statements, hesperidin is not bitter, but is tasteless. and Moiiisoii. “Pceds and Feeding.” 18th cd., ?’able I l l . On the other hand, riaringin, the principal glucoside of grape App.611Iieniv 923!. fruit, is intensely bitter.5z Oranges contain complex glucosePectin glucosides that yield very bitter hygroscopic suhstances which so far have riot been identified. iv~AKuFncTuRE-Studies inaugurated ill the laboratory More positive is the work on the biological value of orange resulted after several years in the cornmercial production of and lemon juices. Goss,l3 Pristor1,~*3~ and Willimott4’.48 citrus pectin in 1923, and since then a group of cliemists have have skiown that ora.nge juice which has been commercially constantly worked oii the prdilems coiinected with its producconcentrated under vacuum to one-sixth or one-seventh of its tion and use.16. Production has increased and the problem original volume retains its vitamins A, B, and C without of standardizing thi nem substance and of devcioping new measurable diminution. Mendel had previously shown the uses for it has occup d the time of half a dozen chemists and pressure of considerable amounts of vitamins A and B in fresh en$necrs. A considerable Merature on pectin has been orange juice. evolved in the last ten ycsrs. Fellenberg’s work” is thoroughThe net result of the labors of analytical and biological ly comprehensive up to 1918. Sucharipa’s monograph3’gives chemists, bacteriologists aiid engineers is the regular produc- a very full review and bibliography arid is perhaps the most tion and sale of standardized concentrated orange juice. complete publicatioii on pectin. To one interested in the This has been officially authorized as an antiscorbutic for chemistry of pectin from the standpoint of production and British merchant ships.‘ sale, the outstanding feature of much published work is the IrishLi has shown the successful use of such concentrated failure to distinguish properly between the various pectin orange juice and lemon juice in carbonated beverages. That preparations and tlie proneness of each worker t o assume that use affordsmie of the large outlets. his or her particular preparation is “pec.tin.” Fortunately this difficulty is partly e1iininat.ed in the most recent articles. Peel Products Tip to now the principal use for peet,inhas been in the making of Peel products, such as candied p e l and marmalade, while jelly, but those who have made the best contributions to of some interest to the consumer and t o the small manufac- our knowledge of the chemistry of pectin-,Y 0 1(1,23,?4.*5.%6,38 turer, have little appeal to the manufacturer who must use a hn,ve not correlated tlieir ficdings with tlie jelling-power, large tonnage of fruit. In such products 50 to 8.5 per cent emulsifying-power, value as a protective colloid, or other of the sale value is in some added purchased commodity, measure of usefulness of the preparations handled. This such as sugar, glass containers, etc. This phase of the in- lack or correlation is a natural gap in the early work to be dustry in Cdiiornia is carried on by comparatively small filled up rapidly, we hope, as commercial pectin is more widely operators, who are able to make a fair profit in conjunction distributed and its usefulness recognized. I
I .
of distilled water, stopper with a rubber stopper or the thumb, and shake vigorously for a few seconds. Remove the stopper or thumb cautiously and allow carbon dioxide to escape without loss of any of the solution. Add the remainder of the 04 e r . of water, thus making a 1 per cent pectin dispersion with a sufficientdegree of accuracy. Shake for 5 to 10 minutes, or until the last visible particle of pectin hrvr, disappeared. If there are any lumps of undispersed material the sample should be discarded and a new one prepared. A very small amount of undissolved pectin mill cause a large error. After dispersion is complete let. the solution stand for a few minutes, until most of the gas bubbles have disappeared, pour about 50 cc. into a small beaker, adjust the temperature to exactly 25’ C. (OF to the teinpera-
GRADS AT
W~icir
PaCTiN T A X R N *ox
s ~ ~ ~ ~ ~ n ! ~ ~ “ , “ , : d 2” Glass Batchn 120
130 140
150 160
iin 180
Is0 200
3 Glass Ratclib
6*omr
Gmml
3.80
3.32
4.40 4.06
3.0Y
3.77
2.88 2.70 2.54 2.40 2 27 2.16
3.30 3.11 2.93 2.78 2.64
1 8s
2.40 2.30
3,62
2.61
210 220 230 2.10 250
2.06 1.96
1.66
2.11 2.03
270
1.80 1.54
1.88
280
280
1.80 1.73
2.20
1.98
INDUSTRIAL AND ENGINEERING CHEMISTRY
1306
The amount to be used is determined by referring to Table
I1 and it depends upon the size of the batch, as well as upon the assumed grade at which jellies are to be made. Weigh out the total amount of sugar indicated in Table I1 and mix a small part of it with the pectin powder in the weighing dish. Approximately 6 parts of sugar to 1 of pectin is sufficient. Mix very thoroughly. Place the total volume of water required (plus about 15 cc. to make up for evaporation) in a tared 4-liter aluminum saucepan or kettle. Heat the water t o about 60' or 70" C. (just about lukewarm) and dump in the pectin-sugar mixture in such a manner that the mixture is submerged a t once and entirely. Any particles allowed to float on the surface are likely to clump and cause trouble in obtaining complete dispersion. Allow the powder to remain submerged for a few seconds. Then stir briskly with the aluminum skimmer until solution is complete, as
/O
/5
20
25
30
35
40
45
50
55
%W€/N SECONDS
Strength Curve for 1 Per Cent Dispersions of Citrus Pectin at 2 5 O c.
Figure 1-Viscosity-Jelly
indicated by the absence of any visible particles. The solution may be heated during the stirring, but it should not be more than lukewarm when the powder is added. When dispersion is complete heat quickly, and, with constant stirring, just to a boil, dump in the rest of the sugar and again bring to a boil with a constant stirring. Place on the balance and adjust the weight quickly by boiling or by adding more sterile water and pour into glasses containing 2 cc. of 32.45 per cent tartaric acid solution. (The tartaric acid solution consists of 8 ounces (avoirdupois) of crystallized tartaric acid dissolved in 1 pint of water.) It is important that the glasses be uniform in shape and size. Hazel Atlas 6-ounce jelly tumbler No. 85 has been adopted as standard. Precautions. The use of more or less than about 6 times the weight of pectin in sugar has been found t o be undesirable. The sugar mixed with the pectin before dispersion aids the dispersion by tending to keep the pectin particles apart until partially dispersed and thoroughly wet. Use of less sugar is less effective and it has been found that use of appreciably more makes the solution more viscous and retards the dispersion of pectin. Lukewarm water is most satisfactory because boiling or very hot water dissolves the sugar so rapidly that it fails in its function of preventing the clumping of pectin particles, and in cold water the dispersion of pectin, being essentially a swelling process, proceeds too slowly. Before the viscosity test was evolved it was necessary to make a number of jellies with each pectin preparation t o determine its grade. When the viscosity method was applied to a number of samples previously graded by making jelly it was found that, while the old grading gave jellies of varying consistency, when made a t the jelly grade indicated by the viscosity curve all jellies had the same consistency. The curve shown in Figure 1 was found satisfactory when applied
Vol. 20, No. 12
to pectins made by the same process from similar raw material. Of course, such a curve plotted for a given pipet cannot be applied to other pipets unless it is shown that they have the same time of outflow for the same pectin solutions. A curve constructed for pectin made by the aluminum precipitation process was found not to apply to pectins obtained from comparable raw material by precipitation with alcohol. The curve for alcohol precipitated pectin was of the same shape but fell below that obtained for aluminum precipitated pectin. In other words, pectins precipitated by alcohol had higher viscosity-jelly grade ratios than pectins precipitated with aluminum. The reasons for this have not been explained, but they probably lie in the nature and quantity of non-pectin material precipitated by alcohol. ?Jorman27showed that the alcohol precipitable material in lemon juice (not necessarily similar to the peel extract) had only 67.2 per cent calcium pectate and had 11.88 per cent ash, even after five reprecipitations with alcohol, followed by thorough washing. Although there is in general a direct relationship between viscosity and jelly strength of pectin solution as developed! in this laboratory and also by Myers and Baker a t Delaware,21 we have obtained a pectin preparation which, according to viscosity curves, should have had a jelly grade of nearly 700, but made satisfactory jelly a t only 220. There is some indication of an effectanalogous to mutarotation, but this has not been thoroughly studied. Similar, though less striking, cases have occurred often enough to prevent our accepting a viscosity test as a final determination of jelly grade, emulsifying power, etc., in all pectin preparations. The reason for this lack of complete correlation is not known, though it is known that the viscosity is affected by the relative proportions of the various pectins, pectic acids, and pectates in the preparation, by the presence of heavy metal salts, by the pH of the solution, etc. It is thought that if all impurities and errors of manipulation could be eliminated and absolute viscosities determined the viscosity-jelly grade curve would be a straight line, but enough data to prove this are not yet available. RATEOF SETTING JELLY-It has been observed that standard jellies made from some pectins will set instantly when the pectin-sugar-water solution is poured onto the acid solution in the container. Others may require several minutes or even hours for setting, but after 24 hours or longer the jellies exhibit similar consistency, elasticity, tenderness, etc. Variations in acidity cause this phenomenon to some extent, but this is not the sole cause. This phenomenon offers an attractive field of study for the physical chemist. The control of the setting time is very important in commercial work. If jelly sets too rapidly it cannot be poured into glasses and may clog pipelines, valves, etc. If i t sets too slowly packing and shipping schedules may be seriously disarranged. What Is Pectin?
There is always before us the question-What is pure pectin? For some time a t least we shall be obliged to regard pectin as a vegetable product that has been fairly well purified by the elimination of mineral ash, etc., of the material from which i t is made and with negligible quantities of impurities added during the process of isolation. Pectin preparations with 0.2 per cent ash and a gold number identical with that of the best gelatin have been prepared. Pectin is a substance used largely in food products and is being made from a t least two raw materials-apples and citrus fruits-by four or five different methods. The principal field of use for the liquid pectin preparation, which usually contains about 4 per cent of pectin bodies, is in the manufacture of jam and jelly. Citrus pectin is produced in dry powder form and is going into a variety of products
December, 1928
I N D U S T R I A L AAVDENGINEERING CHEMISTRY
entirely apart from the jam and jelly field. As near as can be determined, less that half the citrus pectin produced to date has been used in jam or jelly and the proportion so used is decreasing as the other uses are developed. These uses depend on the high emulsifying power and other physical properties of pectin due to its colloidal nature. The only standardization of pectin so far has been on the basis of jellying power, dry pectin preparations of 40, 80, 100, 120, 140, and 160 grade having been marketed, with distinct preference for the 100 and 160 grades. As there are no recognized standards for commercial pectin preparations, it is highly desirable that agreement be reached among producers and users of pectin and the officials enforcing the pure food laws as to standards for pectin preparations and methods for ascertaining the degree of conformity to such standards. It is hoped that close cooperation will be maintained among those interested in order that standards and methods may be agreed upon before too much diversity in these matters is developed by independent workers. Due consideration must be given to the use to which the product is to be put. Unfortunately commercial pectin is not an individual chemical substance that can be assayed for its degree of purity, as can sugar, for instance. It must be judged a t present by empirical tests for the qualities which make it useful. The tests for viscosity of solutions of known concentration here discussed and the direct determination of jelly strength are suggested as a start because they are applicable in connection with the best known use for pectin. Optical properties, pH of solutions a t definite concentration, ash content, freedom from color, flavor, and insoluble matter offer some promise as means of evaluation. We hope other workers will make known the tests they rely on in evaluating pectin and that laboratory workers, pectin users, and food-law enforcement officials will cooperate in the development of satisfactory standards and methods of testing. Summary
The utilization of the surplus citrus fruit crop through channels other than the fresh fruit market has been accomplished through the application of chemistry and engineering. The return from the sale of citrus fruit products does not cover the cost of production of the fruit, but such utilization aids in regulating to some extent the operation of the law of supply and demand. Among the commercial citrus products are citric acid, lemon oil, orange oil, concentrated orange and lemon juices, beverage sirups, peel products, and pectin. Of all these products pectin is the one requiring the most careful atten-
1307
tion to every detail of production and use. Some specific problems relating to its production and use are here presented. Bibliography 1-Ajon, Giorn. ckim. i n d . applicafa, 7, 17 (1924). 2-Ajon, Risisla ilal. essense profumi, 7, 125 (1925). 3-American Chemical Society, Division of Agricultural and Food Chemistry, J . Am. Ckem. Soc., 49, Proc., 37 (1927). 4-British Merchant Shipping (Anti-Scorbutic) Order in Council, April 22, 1927. 5-Chace, U. S. Dept. Agr., Circ. 232 (rev. 1925). 6-Chace, Bur. Plant Ind., Bull. 160 (1909). J . Am. Chem.. Soc., 48, 232 (1926). 7-Dore, C h m . - Z f g . , 28, 197 (1917). 8-Ehrlich, Z . angew. Chem., 40, 1305 (1927). g-Ehrlich, 10-Ehrlich and Sommerfeld, Biockem. Z., 168, 263 (1926). Ibid., 85, 118 (1918). 11-Fellenberg, 12-Gildemeister and Hoffmann, “The Volatile Oils,” 2nd ed., vol. 3, p. 41. 13-Goss. Hilgnrdia, 1, 15 (1925). 14-Hall and Wilson, J . A m . Chem. Soc., 47, 2575 (1925). ls-Irish, Univ. Calif. Agr. Expt. Sta., Bull. 372 (1925). 16--Jameson, J . Chem. Education, 3, 1117 (1926). 17--Maillard, Ann. ckim., 6 , 2 5 8 , 317 (1916). 18--hlead and Guilbert, Univ. Calif. Agr. Expt. S a . , Bull. 409 (19263. 19-Mead and Guilbert, Ibid., 439 (1927). 2 W h l y e r s and Baker, Univ. Del., Bull. 144 (1926). 21-Myers and Baker, Ibid., 149 (1927). J. IND.E N G . CHEX., 8 , 136 (1916). 22-McDermott, 23-Nanji and Xorman, J . SOL. Cizem. I n d . , 45, 337T (1926). 24-Nanji, Paton, and Ling, J . SOL.Ckem. I n d . , 44, 253T (1925). 25--Nelson, J . Am. Chem. Soc., 48, 2412 (1926). 26--Nelson, I b i d . , 48, 2945 (1926). Biockem. J . , 22, 749 (1928). 27-Sorman, 28-Ogston and Moore, Perfumery Essential Oil Record, 18, 126 (1927). I X D . ENCI. CHEM., 18, 1295 (1926). 29-0hn, 30-Parry, “The Chemistry of Essential Oils,” 3rd ed., Vol. 11, p. 319. 31-Perfumevy EssenfiaZ Oil Recoud, 13, 2067 (1922). END.CHEX., 12, 1176 (1920). 32--Poore, J . IND. Ibid., 15, 775 (1923). 33--Poore, J . Roy. N a v . M e d . Sewice, 11, 1 (1926). 34-Priston, 35-Priston, Proc. Roy. S O L .& f e d . , 19, 7 (1926). U. S. Dept. Agr., Bur. Agr. Econ., Circular on Sicilian Lemon 36-Smith, Industry, June 30, 1927. 37--Sucharipa, “Die Pektinstoffe,” 1925. J . Am. Ckem. SOL.,46, 146 (1924). 3S-Sucharipa, 39--Tarr, Univ. Del., Bull. 134 (1923). 4&Tarr, Ibid., 142 (1926). 41-Tarr and Baker, Ibid., 136 (1924). S. Dept. Commerce, IForZd Trade S o t e s on Chemicals and A l l i e J 42-U. Products, 2, No. 25, 3 (1928). 43--U. S. Patent 1,497,884 (1924). Calif. Citrograpk, 12, 422 (1927). 44--Wallschlaeger, Kolloidchem. Eeikeffe, 19, 115 (1924). 45--Wendelmuth, 46-Wil1, IND.ESG. CHEM.,8, 78 (1916). Biockem. J . , 22, 67 (1928). 47-Willimott, 48-‘A7illimott, Ibid., 22, 535 (1928). 49-Wilson, J. IND.EXG. CHEM., 13, 554 (1921). 50--Wilson, Ckem. M e t . Eng., 29, 787 (1923). 51-Wilson, IND.ESG. CHEM.,17, 1065 (1925). 52--Zoller, Ibid., 10, 365 (1918).
Chemistry and the Flavoring Extract Industry Bernard H. Smith VIRGINIADAREEXTRACT Co., I X C . ,BROOKLYN, N.Y.
I
N THE wide realm of chemistry there are few things more
important than flavor. Did you have a good cup of coffee this morning? That was flavor. Was the wellbrowned bacon better than usual? Flavor again. Was the butter above reproach? Again a matter of flavor. Do you particularly enjoy the communications of Doctors Slosson, Herty, Little, and JT‘iley? That is literary flavor. For the dictionary tells us that flavor may be “a predominating or a characterizing quality of anything, especially of
literary 1%-ork.” The flavoring industry therefore covers a wide and interesting field. We have, however, more restricting definitions. The Oxford Dictionary says flavor is “that element in the taste of a substance which depends on the cooperation of the sense of smell.” It is that which gratifies the palate: relish-savor. It is well established that the tongue and the palate can appreciate only a part of what we know as flavor. Bitter and sweet, salt and sour are indicated by the tongue, but odor
