December, 1928
INDUSTRIAL AND ENGINEERING CHEMISTRY
59-Fitzgerald, Bohart, and Kohman, “Black Discoloration i n Canned Corn,” Natl. Canners Assocn., Bull. 18-L (1922). fi-eidel, “Control of Corn Quality b y Chemical and Physical Analysis,” Canner, Convention h-o., 1925, p. 134; Canning Trade, Convention KO., 1925, p. 90. 61-Givens and McClugage, “ T h e Effect of Heat and Age upon t h e Antiscorbutic Vitamin in Tomatoes,” Pvoc. SOC.Exptl. R i d . M e d . , 18, 164 (1921). 62--Gowen, “Effect on Quality of Holding Shelled Peas,” Canning Trade. Convention No., 1928, p. 7 4 ; Canning A g e , Convention N o . , 1928, p. 202; Canner, Convention No., 1928, p , 112. 03-Hess a n d Unger, “ T h e Effect of Age, H e a t , and Reaction on Antiscorbutic Foods,” J . Bid. Chem., 38,293 (1919). fi4--Kohman, “Vitamins in Canned Foods,” Natl. Canners Assocn., Bull. 19-L (revised 1927). B b K o h m a n , E d d y , et a!., “Vitamins in Canned Foods,” IND. EXG CHEM.,15,273 (1923); 16, 52, 1261 (1924); 17,69 (1925); 18,85, 302 (1926); 2 0 , 202 (1928). 66-Kohman, “Canned Foods,” Hygeio, 6, 639 (1928). 67-Kohman and Sanborn, “Storage Temperatures for Canned Fruits,” Natl. Canners’ Assocn., Bull. 23-L (1927). B&Kohman, “Phenol-Chlorine Water Pollution,” IND. ENG. CHEM., 111, 518 (1923). R+Kohman, “Lye Hominy: I t s Discoloration and a New Process for I t s Manufacture,” I b i d . , 14, 415 (1922).
1289
7@-Kohman, “Discoloration in Canned Sweet Potatoes,” Ibid., 13, 634 (1921). 71-Magoon and Culpepper, “A S t u d y of the Factors Affecting Temperature Changes in the Container during t h e Canning of Fruits and Vegetables,” U S. Dept. Agr., Bull. 966 (1921). 72-Magoon and Culpepper, “Relation of Initial Temperature t o Pressure, Vacuum and Temperature Changes in the Container during Canning Operations,” Ibid., 1022 (1922). 73-Meister, “Controlling Consistency of Canned Corn,” Canner, 23 (January 23, 1926). 74-Meister, “Variations in Consistency of Canned Corn,” Ibid., 19 (June 18, 1927). 75--Meister, “Study of Solubility of Certain Metals and Their Effect on Color of Canned Corn,” Ibid.. 17 ( M a y 12, 1928). 76-Miller, “Vitamins A, B, and C in Fresh and Canned Pineapple,” J . Home Econ., 16, 18, 74 (1924); 17,377 (1925). 77-Purcell and Hickey, “Occurrence of Struvite in Canned Shrimp.” A n a l y s t , 47, 16 (1922). 78-Savage, “The Methods Used for the Inspection of Canned Foods,” Food Investigation Board, Specin! R e p t . 3 (1920); 10 (1922). 79-Shostrum, Clough, and Clark, “A Chemical S t u d y of Canned Salmon,” IXD.ENG.CHEM.,16,283 (1924). S+Stevenson, “Discoloration in Canned Foods,” Canning Trade, 22 (February 2, 1925).
Chemistry and the Beverage Industry F. M. Boyles JACK
BEVERAGES, INC., BROOKLYN, N. Y.
HE subject matter of this paper will be confined to
T
carbonated beverages, as distinguished from the socalled cereal beverages or brewed drinks. The beverage industry, strictly speaking, is not a chemical industry, but its progress and development are very closely tied up with our science. Although the chemist in this industry has not been as spectacular a performer as in many other industries, he has been responsible not only for the industry itself but very largely for what progress it has made. Of course we could not have attained the position we occupy today without our many truly wonderful mechanical appliances, credit for which is due to the mechanical engineer. It mas Priestley, the preacher-chemist, the discoverer of oxygen, who did the pioneer work with carbon dioxide gas, or “fixed air,” as he called it, and especially the solution of this gas in water, upon which the industry has been built. I could not describe to you nearly as interestingly as Priestley himself has done those first epochal experiments, which he records in this language: It was in consequence of living for some time in the neighborhood of a public brewery, a little after mid-summer in 1767, that I was induced t o make experiments on fixed air, of which there is always a large body ready formed on the surface of the fermenting liquor. A person who is quite a stranger to the properties of this kind of air would be agreeably amused with extinguishing lighted candles, or chips of wood in it, as it lies upon the surface of the fermenting liquor. Considering the near affinity between water and fixed air, I concluded that if a quantity of water was placed near the yeast of the fermenting liquor, it would not fail to imbibe that air, and thereby acquire the principal properties of Pyrmont and some other medicinal mineral waters. Accordingly, I found that when the surface of the water was considerable, it always acquired the pleasant aciduloiis taste that Pyrmont water has. The readiest way of impregnating water with this virtue in these circumstances is to take two vessels and to keep pouring the water from one into the other, when they are both of them held as near the yeast as possible; for by this means a quantity of surface is exposed t o the air, and the surface is also continually changing. In this manner, I have sometimes, in the space of two or three minutes, made a glass of exceedingly pleasant sparkling water, which could hardly be distinguished from very good Pyrmont, or rather Seltzer water.
One would naturally think that having actually impregnated common water with fixed air, produced in a brewery, I should immediately have set about doing the same thing with air let loose from chalk, etc., by some of the stronger acids. But, easy as the practice proved to be, no method of doing i t a t that time occurred to me. I still continued to make my Pyrmont water in the manner above mentioned till I left that situation, which was about the end of the summer of 1768; and from that time, being engaged in other similar pursuits, I made no more of the Pyrmont water till the spring of the year 1772. If water be only in contact with fixed air, it will begin to imbibe it, but the mixture is greatly accelerated by agitation, which is continually bringing fresh particles of air and water into contact All that is necessary, therefore, to make this process expeditious and effectual, is first to procure a sufficient quantity of this fixed air, and then to contrive a method by which the air and water may be strongly agitated in the same vessel, without any danger of admitting the common air t o them; and this is easily done by first filling any vessel with water, and introducing the fixed air to it, while it stands inverted in another vessel of water. The pressure of the atmosphere assists very considerably in keeping fixed air confined in water, for in an exhausted receiver, Pyrmont water will absolutely boil by the copious discharge of its air. This is also the reason why beer and ale froth so much in vacuo. I do not doubt, therefore, that by the help of a condensing engine, water might be much more highly impregnated with the virtues of the Pyrmont spring, and it would not be difficult to contrive a method of doing it.
Prophetic words, clearly pointing the way to the carbonated beverage industry! It is of interest to note here that Priestley’s source of carbon dioxide, namely, fermenting vats, is today the source of a very large part of the gas used in carbonated beverages. Priestley’s gas, however, with its entrained vapors, carrying along the flavors and odors of fermentation, could not be used in delicately flavored drinks. The chemist therefore has purified this gas by eliminating all of the objectionable substances. Outstanding figures in this work are Backhaus and his associates who, among other things, utilized activated carbon, another product of chemical ingenuity, to absorb the undesirable things from the gas. I shall not attempt to trace the history of the develop ment of carbonated beverages. A carbonated beverage is essentially a solution of carbon dioxide, sweetened, fla-
1290
INDUSTRIAL AND ENGINEERING CHEMISTRY
vored, and usually acidified. Casually i t would not seem that the chemist could have a very deep interest in such a seemingiy simple product or that he would choose to talk very lustily about what he had done to bring it into being and develop it. Tho true chemist, of course, is interested more in the solution of the problem before him than in the rewards t.liat may accrue to him from its solution. There were many such men in the early stages of this industry.
Vol. 20, No. 12
occasional aldehyde and small quantities of essential oils, most of them contained as sweeteners, chloroform, and
nitrous ether. Our principal raw materials of tho8e days were ethyl acetate, acetaldehyde, ethyl butyrate, amyl acetate, ethyl formate, oenanthric ether, methyl salicylate, sebacic ether, amyl alcohol, and chloroform. Contrast these with the raw materials of today, products of chemical research: The higher alcohols and esters up to and including octodccylic; tho higher aldehydes, beginning with CZ4and Development of Flavors iiicluding the Cis, C,i, Ce, and Ca; aldehydes of the aromatic As late as about thirty years ago $lie industry had not series, such as beneilic and cinnamic, vanillin, piperonal, and such as amy1, propyl, and and 'lie developed beyond three flavored drinks--strawberry, lemon, sarsaparilla, popularly known red, Tvhite, and black, ketones. These substances, in conjunction with anethol, was crimson \vith cocliiueal and flavored llritI, =fro4 ewenol, coumarin, and the alcohok extractives of The acetate,a,ld oil wet,ahle prodiicts, such as fenugreek, St. John's bread, coffee, clrloroform, a lnixtllre of nitrous and cocoa,,and tlie concentrated fruit juices provide a wealth ~h~ lemon was macle by dissol\,i,,g lemoii of of material from which unlimited varieties of flavors may be made. The work of Power, Klebei-, Cliesnut, and ot>herson the flavoring constituents of the apple, banma, grape, stravberry, etc., lias given us some very valiiahle basic ideas as t o the make-up of the substances responsible for tbe flavor of these fruits. With these substances synthetically made s e have procceded in many instances t,o improve upon nature. Core has sliovn us how to eliminate practically all of the m t e r from fruit juices by freezing, thus producing the flavor in eoncentrated form and without alteration. Other cliemists are doing the same thing by highly refined vacuum processes. A very interesting problem confront.ingthe industry today is the production of highly cont:entrat,cd fruit juices witli unaltered flavor which will not cause fermentation in tlie finished drink. OUT present concentrated fruit juices, rich in sugars, proteins, and allinminous substances, harbor Covrlesy of Miller Manufacturing Co.. Boinbridgr, Go. nticroBrgauisms that give the bottler trouble and can only Finure 1-Waahine Machine (in Bsckeround) and Automatic Filling Machlnes (in Foreground) Used in a Modern Bottling occasiolmlly be overcome by very high carbonation, which Plant is in itselS imdesirable because excessive quantities of carbon dioxide mask the delicate flavors of ilie fruits and ruin the oil io alaollol, t,hrowing illto a amount of t'lie skimming off tlie separated oil, and adding sugar to the drink It is axiomatic in the industry that fruit flavors cannot Ti.as fiaflavored R.ater to make a siruri, The with oil of sassafrns and colored T ; ~he~ highly carbonated. Tliis situat,ion has been rendered acute by the recent dccisirm of the Federal Trade Commission, a very imposing beginning. ~ 1 , ~ now entered the indust,ry again and gave his xliieh, in the case of imitation grape, takes the position that first attent.ion to the development of flal.ors. ~l~~ enact- a drink shall not be hranded with tlie name OS the frilit, ~VEII when qualified by the word "imitation," utiIcss suo11 ulent of the ~ ~~~~d dand nmgs ~ ~~t ~ made~ it imperat.jve l that the chemist his efforts to produce gavors to drink is prepared wholly from the juice of the fruit. The S R m e principic, of course, would apply to all other fruit meet it,s provisions. ~ l ~ of ~ course, , ~ is~ the , most important ingredient in drinks. The soundness, and indeed the legality, of this any soft drink, For. no matter how fine the product is in decision is questionable. It is not within the province of this paper to discuss the other respects, if the flavor is not to tile palato tho sales ~ 1 4 1be nil. The result today is an ilnposing relation of chemistry t,o the coal-tar color industry, but it of both natmai and flavors, many of tiie should be said that without our certified colors the hwerage industry could llot have made the advance it has, for the artificial ones being Inore popular than the natural simple reason that drinks unattractive to tlie eye are without as is attested by the r.olume OS sales and recentiJrby R. 15, Smith's very interest,ing, demonstration. Mr. Smith conto the consumer. ducted a unique series of tests to ascertain the taste preference Effect of Water of a group of ninety-eight persons of different agcs, sexes, and orcupations, bctrrccri grape juice niid a modern carbonWater constitutes tho bulk of all o11r hvCTages. LVhile atcd beverage OS the fortified grape type. He fouiid that the iudustry has from the begiirnirig realized the irnpoftance iO.5 per cent prferreri the srt,ificial fla1.0~. of pure w&r, it is the chemist who has dcmmstrnted this The derelopmctit of the host of synthetic organic cliemicals irnportnnce arrd pointed the "11)- to means ~ k i i t nretl>ods i IrE of the aromatic niid diplmtic series has put into tlie hands purification in case tlte s u ~ & at hand is I l o t of sat of the flavor maiii~fncturerthe material from which his qii:dity. may rrie,,tion briefly ,%.herein I,e 1;, cliemist lins mado some truly wonderful flavors. S o t t,he iridu many years ago our so-called fruit flavors were practically Cliemical agents, sucir as chlorine and ozoric, or p1,ysical alwnys ethereal; that is to say, they were made up of combi- processcs, siicli as ultra-violet light and distillation, produce nations OS the csters of t l i c l o i w alipliatic series, with an a safe writer. It is essential to avoid cxcessive rjlllttitities
December, 1928
INDUSTRIAL AND E,?% VNEERING CHEMISTRY
of chlorine and ozone, as small quantities of either will develop off-flavor and bleach the finished drink. Water t.reated with ultra-violet light must be clear and free from suspended matter which would act as parasols in whose shade the bacteria would be shielded. For the removal of excessive mineral matter or hardness, base exchange by the use of zeolites and distillation are the best methods. The salts of calcium, magnesium, and sodium impart a taste to water. I n small quantities these salts may improve the flavor of drinks, hut excessive quantities may affect them adversely. It is also probable that very hard waters have a tendency to precipitate colors. Iron and magnesium in water may be responsible for clouding and development of specks. This work suggests the following problems yet to be solved: What is the relative effect of the salts of sodium on flavors as compared with equivalent quantities of calcium and magnesium? What kind and what quantities of mineral salts cause sediments to develop due to reaction with coloring matters? Prevention of Spoilage
The chemist, collaborating with the bacteriologist, has shown the bottler how to avoid many of his spoilage problems. Carbon dioxide has been shown to have a distinct germicidal effect upon bacteria (which are often the cause of cloudiness in beverages), the magnitude increasing with the pressure of the gas. Despite its germicidal activity, the use of carbon dioxide must be preceded by strict sanitary precautions. The presence of acid in soft drinks bas been shown to have a decided influence on retardiiig the growth of bacteria. It bas been shown that approximately 80 per cent of the spoilage in bottled beverages is due to yeasts. The sources of the yeasts arc air, dirty bottles, and sugar. The feliowship established by the American Bottlers of Carbonated Beverages at Iowa State College under Professor Ruchanan has done notable work along these lines and has given the industry very accurate information on methods for preparing sterile sirup and on the proper quantity of alkali and the proper degree of heat to be used in the water for washing bottles so as to avoid spoilage from both bacterial and yeast. infection. Bottled Milk Chocolate
The latest development in the industry is bottled milk chocolate. Enterprising bottlers, in casting ahout for iiew items with which to increase their business, particularly during the off-season, fell upon the domesticated cup of cocoa and bottled it. That is just about what is being offered rmder various names featuring the words “milk” and “chocolate.” These beverages took the bottler out of his field and brought him face to face with chemical and bacteriological problems which be found could not be solved without scientific investiiation. Most of the bottlers who enthusiastically invested when the “milk chocolate” boom first started soon gave up. But the intrinsic merit of this new heverage makes a study of its prohlems worth while. It is generally conceded that the sugar in the usual carhonated beverage gives it a definite nutritive value. Kow “milk chocolate” contains, besides sugar, a fair amount of milk solids and cocoa. No one needs to be reminded of the nutritive value of these, but it should be pointed out that the beverage now contains proteins and fat also, and thus is the only bottled beverage which approaches a balanced food. The refreshing and mildly stimulating properties of cocoa are generally appreciated, and the beverage is equally tasty served ice-cold or piping bot, according to the
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demands of the weat.her. So it is bound to be a good yearround stand-by for t.he bottler who learns how to handle it. Like all highly nutritive foods, milk chocolate beverages are quickly destroyed by bacteria. The most resistant of all microkrganisms thrive in milk. After experimenting with chemical preservatives without success and sufferiug heavy losses, the industry found that complete sterilization after bottling with steam at 15 pounds is the only way that, the beverage can he preserved. It is this sterilization process which is giving the average bottler so much trouble. The milk sometimes curdles, owing to sinall quantities of acid normally occurring in the various ingredients and becoiniiig very active at 240”F., the sterilizing temperature. The following data, which are by no means complete, are based 011 work now under way in the author’s Iahoratory: Titrations of the cL:oa, milk, and simps, using pbenolphthalein as the indicator, showed practically no difference when those producing a had hatch were compared with those yielding excellent results. It was found, however, that rendering the hatch just alkaline to plienolpl~thaleinbefore adding milk preveiited curdling in every case. But this alkalinity produced a darker hevcrege, which gave the impression that not much milk was heing used when in fact there was considerable. This showed, t,lieii, that there existed, in the rats material, small arnounts of acid which varied from time to time and must he exact,ly neutralized to prevent curdling on the one hand and off-color 011 the other. 1 0
Covrlrsy
01Zoslrow Mochinc Co., Boilirnorc. M d .
Figure 2-Horizontal
Bottler’s Sterilizer
The best indication of acidity is, of course, tho hydrogenion concentration. Accordingly, a study of the pH of the various ingredients dissolved or suspended in vator in about the same concentration as in the finished beverage washegun. The pH of numerous curdled specimens was also determined. The lowest pH so found, 4.6, afforded a temporary maximum acidity limit which could be tolerated. The following acidity limits of available materials resulted in satisfactory hatches: M*I*RI*L
Skim milk ~ o w d e r
Cocoa corn sirups
commercia1 cnae JiiupJ= Cif” water
AEXD~ Llmr ~Y Max. Mi“.
PI2
PI1
6.25 6.20 3.2 3.2
6.86 6.25 4.44 6.8
6 -.8. H0”W 3.6 When more than 10 per cent oi ihc suzar content there sirups curdlinz occurred.
X f i
4.2 W ~ Pobtained
with
The effect of free acid on the milk coutent of the beverage was next determined. A sample containing only the milk powder and sugar dissolved in the regulnr amount of water was made. 0.1 N citric acid was added in 0.2 cc. quantities, and the pH was determined after each addition. The initial pH was 6.8. Curdling was apparent after the addi-
INDUSTRIAL AND ENGINEERING CHEMISTRY
1292
tion of 2 cc., but the pH value still remained 6.8. It was not until 5 cc. of acid had been added that the pH changed. Then it suddenly jumped to 5.0. Coagulation was practically complete. To a similar sample 0.5 cc. of the acid was then added. After standing for one hour it showed no sign of curdling. The sample was bottled and put through the sterilization process. Complete precipitation resulted. This proved that the milk was highly buffered and could tolerate only a very small amount of acid without showing a t least partial curdling on sterilizing. As there was practically no difference in the titratable acid in the various ingredients, their pH afforded the only indication of their fitness. pH values less than 6.0 should be adjusted with a suitable alkali to p H 7.0. Sometimes the cause of curdling can be traced to bottling plant conditions and lack of facilities to properly reveal acid conditions. It is of the utmost importance that no carbon dioxide be present in milk chocolate. In one plant visited, batch after batch was curdled owing to a small amount of carbon dioxide which leaked past a closed valve. It was not until the gas line was removed that a satisfactory batch could be obtained.
Vol. 20, No. 12
Conclusion
Such has been the progress of the industry under the guidance of its chemists, until now the carbonated beverage is as much a part of American life as work, food, and sports. No picnic, ball game, or other sporting event could develop its normal enthusiasm without the sustaining effect that the pop bottle exerts on mob lung power. Dressed in a more stately package and consumed under more dignified surroundings, our soda water has become a standard factor in promoting good cheer a t home and a t the club. It is a great industry, and the chemist is a t work, improving here, developing a novelty there, and defending it against arbitrary and fanatical legislation, seeking to impose prejudiced and impractical standards. He will, in the future, as in the past, draw copiously on the sister sciences of bacteriology and applied mechanics for inspiration and suggestion. And he is cheered by the hope that he too may, along the highways and byways of his work, find new facts, and that these, when classified and added to that great body of organized knowledge which constitutes our science, will make it more complete and extend its service.
Chemistry and the Baking Industry C . B. Morison A-RICAN INSTITUTE OF BAKING, CHICAGO, ILL.
HE importance of chemistry and the related sciences
T
for the better understanding and for the improvement of the art of baking has been emphasized by chemists for over one hundred and fifty years. This is a comparatively short time in the history of baking, but not in the history of chemistry, since it runs parallel with the modern development ,pf this science from the time of Lavoisier to contemporary theories of atomic structure. The chemist’s interest in baking did not have its origin in the theoretical aspects of t.he problem. Chemistry was first brought to the attention of the bakers on the basis of its utility and application for a better knowledge of the art, improvement of baking conditions, and the technical education of bakers. This was surely the original interest of those eighteenth century chemists in France who first began to study French bakery methods and conditions by actual contact with the baker. These men have a just claim t o the title of pioneers in this field of applied chemistry. I n 1767 Malouin published his “Description,”’ which greatly expanded the article on baking in the Encyclopedie of Diderot of 1763. Malouin’s work called attention to the value of science and its methods for the improvement of baking, and provided a basis for the work of the great French food chemist Parmentier, who early in his useful career became interested in the art and labored until his death for the education and advancement of the craft. Parmentier’s great work on baking,2 published in 1778, received the approbation of the Royal Academy of Science as a work which gave t o the art “une heureuse application des conoissances Physiques et Chemiques.” It is a landmark in the history of chemistry as applied to baking. It soon became the recognized authority in the scientific literature of the “Description et Details des Arts du Meunier, du Vermicellier et du Boulanger, avec une Histoire abregee de la Boulengerie, et un Dictionnaire de ces Arts,” Paris, 1767. 8 “Le Parfait Boulanger. ou Trait6 Complet sur la Fabrication et IC Commerce du Pain,” Paris, 1778.
subject and a handbook for the progressive baker, and was translated into foreign languages. This work had a real influence in bringing some appreciation of the value of science in baking practice by giving the baker information which even now is of practical value. Parmentier was the original advocate of technical education for bakers, and his influence led to the foundation of a school of baking in Paris, which was destroyed in the midst of a flourishing career by the French revolutionists, who had no need for chemists and sent Lavoisier to the guillotine. After Parmentier, who is entitled to the credit of having brought some measure of appreciation for scientific control into the bakery and a better understanding of the art, but little progress was made in the chemistry of baking until the work of Dumas in the 1840’s. Between the time of Parmentier and Dumas the rise of analytical chemistry had made possible a better knowledge of the composition of wheat and other cereals, flours, and bread, in common with other foods, but no one had published a comprehensive study of the chemistry of baking comparable to the original work of Parmentier. I n 1843 Dumas published an article on chemistry as applied t o baking, which brought the subject of baking up t o date and included a r6sumb of some of his own investigations.s This article was a mine of information for those interested, and was used by many writers of textbooks and encyclopedias for the preparation of original articles. Dumas, who made a thorough study of baking, came to the optimistic conclusion that, ‘(l’artde la Boulangerie, naguere si arri6re, tend B s’elever au rang des industries manufacturieres les mieux raisone6s.” He also concluded that the most satisfactory way to determine the baking value of flour W R S by a carefully controlled baking test, which in 1928 is the opinion of most cereal chemists. The work of Parmentier and Dumas has been mentioned for the purpose of indicating that the chemist’s interest in 8
“Traite de Chimie, AppKqu6e aux Arts,“tome 6, Paris, 1843.
