TX 38? Issued Scptombcr 5, 1!)0S. U. S. DEPARTMENT OF AGRICULTURE, BUREAU OF CHEMISTRY— BULLETIN No. 114. H- W. WILEY, Cliirf c.f Buroan. MEAT EXTRACTS AND SIMILAR PREPARATIONS, INCLUDING STUDIES OF THE :\1ETH0DS OF ANALYSIS EMPLOYED. ]'.Y W. "D. P.IGELOW, CHIEF, DIVISION OV FOODS, AND Y. ('. COOK, !'I[VSIOI.O(;lCAL (TIK.MIST. WASHINGTON: GOVERNMENT PRINTING OFFICE. 19 8. Book - U .-Tf V -^ Issued September 5, 3 DOS. U. S. DEPARTMENT OI' AGRICULTURE. BUREAU OF CHEMISTRY BULLETIN No. 114. ir \V. WILKV. (Iiiif ..f lliinuli. MEAT EXTRACTR AND SIMIIAR PREPARATIONS, INCLUDING STUDIES OF TUK METHODS OF ANALYSIS EMPEOYED. BY W. 1). J'.IGELOW, CHIEF, IllVISIOX OI' FOODS, AND F. C. COOK, PHYSIOUXilCAL CIIEiMIST. WASHINGTON: GOVERNMKNT TKIXTINt! OFFICE. 1 y () 8 . ■J i> SE?14»908 1? LEITER Ol^" TRANSMITTAL. U. S. Department of AciKiciTr.TiTRE, Bureau ov Chemistry, Wai:hlngton, D. ('., October W, l!H)7. Sir: I have llic lioiKir to transmit lierovvith the results of a chciii- ical study of various preparations made from meat, anil some sub- stances used to adulterate such products. In addition, conunents on the nutritive value of meat extracts and similar products have been compiled from the literature of the subject. The wide use of preparations of this nature by invalids and others seekinara- tioiis otfered when the analyses were submitted to them. 7 MEAT EXTEACTS. Table I. — Description of saniplrs analyzed. SOLID MEAT EXTRAfT-CSEK TABLE II). Serial num- ber. Name of preparation. Manufacturer. 15867 15868 15869 "Rex" Brand Beef Extract Liebig's Extract of Meat The Cudahy Packing Company, Omaha, Nelir. Liebig's Extract of Miiit Company, .\nt\verp. Belgium. (Agents, CorneillH, Huvid & Co., 120 Hudson street, New York, N. Y.) 16048 Libby, McNeill and Libbv, Chicago, 111. Swift" and Company, Chicago, III. G. II. Ilanmiond Company, Chicago, 111. 16049 1(1060 Beef Extract I'LUID MEAT EXTRACTS— (SEE TABLE IV). 15964 15965 Concentrated Fluid Beel Extract Armour and Company, Chicago, 111. John Wyeth and Brother. Philadelphia, Pa. Valentine's Meat .luief Cnnii)any. Richmond, Va. Armour and Company, riiieago. 111. The Cndahv I'aekiuK C"iupaiiv, Omaha, Nebr. Cibils Companv. Iniportrrs, Nrw York, N. Y. The .\I..squira .luliu Food Company, Detroit. Mich. (Agents, Parke, Uavis A: Co.) 15966 Meilt Juice.. 15977 1.5979 Vigoral *■ Rex" Fluid Bex-f Extract 15990 15991 Fluid Extract of Beef Fluid Beef Jelly MISCELLANEOUS PREPARATIONS— (SEE TABLE IX). 15911 15903 15976 16040 Bouillon Capsules Bovril, Seasoned Beef Jelly, Mosquora Extract of Boef. Essence of Beef 16044 Predigested Beef 15870 Soluble Beef 15908 ' Bovox Essence of Beef. 15909 Johnson's Fluid Beef. 15988 159S9 16043 15978 15910 16037 16039 16041 American Brand Extract of Beef Bovinine Concentrated Beef Essence of Mutton Liquid Food (extnictof l)eef, mutton, and fruits). Maggi's Bouillon Peptonized Beef. Rose Beef Extract and Vegetal)le Tablets. Leube-Roscnthal's Beef Solution Malted Meat Extract of Beef Beef Peptonoids Royal Specialty Company, New York, N. Y. Bovril (Ltd.), "London, England. (Park and Tilford, agents, New York, N. Y.) The Mosquera-Julia Food Company, Detroit, Mich. (Agents, Parke. Davis & Co.) Brand and Company (Ltd.). Mayfair, Vauxhall, S. Vi. London. (Fougera Company, agents, New York N. Y.) H. K. Mulford Company. Philadelphia, Pa. Armour and Company. Chicago. III. The Bovox Company, Boston. Mass. Bovril (Ltd.). Montreal. Canada. American Beef E.xtract Company. Boston. Mass. The Bovinine Company, 75 W. Houston street, New York. The London Essence Company, London, England. (W. B. Hard and Company, IS Cedar street. New York, N. Y.) Murdock Liquid Food Company, Boston, Mass. The Maggi Company, Kempttal, Switzerland. (J. P. Smith and Company, agents, 90 Hudson street. New York, N. Y.) P. B. Rose. {General agents. Chapman, Green and Company, Chicago, 111.) Armour and Company, Chicago, III. Ph. Rndisch. (Cheppe and Schur. agents, Third avenue and 60th street. New York, N. Y.) American Malted Meat Company, South Milwaukee, Wis. The Arlington Chemical Company, Yonkers, N. Y. COMMENT BY MANUFACTURERS. The analyses of the commercial pnxhicts examined were referred to the manufacturers or their agents, ami the following extracts from the replies received are submitted. The letters addressed to the American Beef Extract Company, Boston, Mass.; American Malted Meat Company, South Mihvaukee, Wis.; Cibils Company, New York City; W. B. Hurd and Company, IS Cedar street, New York City, and to Chapman, Green and Company, Chicago, 111,, were returned unclaimed. The following manufacturers COMMENT BY MANUFACTURERS. 9 replied, but ofl'ered no oriticisni of tlie analyses: Tiie Bovinine Com- pany, 75 West Houston street. New York City; the Muidock Li(|ui(l Food Company, Boston, Mass.; Fougera and Company, 00 Beeknian street, New York City, and the Liebig's Extract of Meat Company. From the following manufacturers no reply was received: Swift and Company, Chicago, 111.; G. II. Hammond Company-, Chicago, 111.; Cibils Company, New York City; Royalty Specialty Company, New York City; The Bovox Company, Boste determined and i)ul)lished l)y you. » » * We believe, in view of the facts as given herewith, that in justice to us. and ini>rder that the object of the Bureau of Chemistiy be aic-oiii]i!ishcd. an analysis of the Dry Peptonoids (Soluble) should be made by you and puldi.shed in accordance with the provisions of the act of Ccmgress cited in your letter. [In accordance with the retpiest of The Arlington Chemical Com- pany, the following analysis of the "Dry Peptonoids (Solul)le)," as made by their chemist, December 1.5, 190G, is given in this connection:] Pit (int. M( listiu'e 5. () Nitrogenous compounds (N x G.2.5) :ffl. 5 Total carbohydrates, after inversion -Jli. 7 Ether extract (fats and lipoids) 0. :} Mineral constituents (ash) 5.8 Insoluble material 1.0 Comment ty autJiors. — The writer was informed that as the entire report represented the samples on the market in the winter of 190.5-6 it would not be just to other manufacturers to bring the work up to date in one case alone. Armour and Company. N09. 15869, 15870, 15910, 13904, luul l.Wi;7. The results are very different from what we should expect, anil from results whicli we have oljtained in our experience with these products. The most striking feature is the low results you report on kreatin and krcaliiiin. As a mailer of fact We find that it makes a gri-at difference wliicb aielhod is iisnl in deter- 10 MEAT EXTRACTS. mining total kreatinin. The motliod we use in tliis lalioratory is the modification of Folin's method as suggested l)y Gi'indley and Woods. From our experience we pre- sume that the method you use is the same as that outlined in the proposed methods for the cooperative work on the sample of beef extract sent out June 3, 1907. Our results on this cooperative work, as well as our analyses of several other samples, give materially low(:'r figures for total kreatinin << liy the method furnished us by Mr. Cook in his letter of June 3 than by the method of Grindley and Woods. We also note that the percentage of proteid^ as determined in fluid extract of heel is not proportional to the proteid as determined in solid extract. Inasmuch as one is made from the other Ijy mere solution in water, we are unaljle to find an explanation for this difference, assuming that both were determined by the same method. We note also that the total nitrogen in these two preparations is not proportional. Among other features that we note we shall mention only the unusually high moisture in Soluble Beef. It is considerably higher than our records. Comment ly authors. — The fact that some of the results var^' with the method used has ah-eady been discu.ssed, and this is especiaUy the case with kreatinin. As tlie same method was appHed to all the sam- ples reported, no injustice is done. The percentage of moisture and total nitrogen in the solid and fluid extract are proportional, but the percentage of total proteids in the fluid extract is lower than in the solid extract. This, however, is compensated for by a correspondingly higher percentage of 'meat bases. This may be due to the failure of the tannin-salt reagent to precipitate all of the proteid, and consecpiently a higher meat base result is obtained. BovRii, Limited. No. 15909. W'e have to thank you for your favor of September 21, but we can not help thinking that there has l)een a inisunderstaiuling somehow, for our standard for moisture and ash'' in Johnston's Fluid Beef is 32 per cent and 19 per cent, respectively. A careful analysis of the last three batches made has given— Mnistun*. .\.sli. No. 1 33. (i9 19.34 2 31.22 IS. SO 3 32. 61 19. 20 We are under the impression that llie sample you have analyzed is a cordial and not the original Johnston's Fluid Beef. The latter is a paste standardized as aliove, whereas the cordial i:; a liquid prepared with a higher percentage of moisture for con- venient use in saloons, etc. Coiiunent by authors. — The product reported under No. 15909 was labeled as "Johnson's Fluid Beef." Owing to the statement of the manufacturer, a new sample was obtained on the market and the moisture and ash determined again. This sample contained 38.62 per cent of water and 13.18 per cent of ash. « See Tables II, IV. and IX. !> See Tables III, V, and X. « See Table IX, page 26. COMMENT BY MANUFACTURERS. 11 The Cudahy Packixo Company. Nos. 15SW .ind 15979. For your information we wish to say that the Extract of Beef we are now putting on the market is, in our estimation, a superior article to the preparation we were sellini,' at that time, and we are having an analysis made of our present iiuinulail\u'e and will sulimit the figures to you as foon as completed. LiBBY, McXeili. and Libby. In replyto your favor of .September 21 , in reference to your analysis of our Premier Brand Extract of Beef, will state that we have carefully examined our analyses for an extended period and find that our determinations are not in accordance with your analysis. You, of course, recognize that in the making of this product there is sure to be considerable variation and we feel sure your Department does not expect each batch to be an exact duplicate of every fjther one. * * * We have had our chemist analyze samples from our present stock and sulmiit the following, whicharetheaverageof his determinations of the various samples analyzed — for cent. 1 I'.T ivnt. Moisture 19.54 | Total nitrogen 7.(50 Ash 27. 80 I Ether extract .53 Sodium chlnrid 11.32 j Lactic acid 7.!i7 Proteid 13. 12 j Ammonia .50 Meat bases 18. 12 , Undetermined 12. 3-1 Total kreatinin .5. 40 Comment hy authors. — An uiisiicce.s.sful atteiiii)f wn.s niailc to sociirp another sample of this product. II. K. MuLFonn ('omi-any. X comparison of the results with analyses on record in our laltoratory agree quite well in the main. * * * Some eighteen months ago we revised our lal>el aiul litera- ture on Predigested Beef iitan effort to have our statements conservative and in accord- ance with the standards established through assay of the linished product. P.^RKE, Davls and Company. Nos. 15970 and 15991. Acknowledging the receipt of your two reports ujjon Mosqtiera Beef .Telly (Extract of Beef) and Mosquera Fluid Beef .Telly, we beg to say that we ha\e no jjarticular criti- cism to offer to the results as outlined any further than to say that they agree in a gen- eral way with the data which we have obtained and which ha\'e been (jbtained by others in the analysis of these two products. * * * You of course realize that the results obtained from the analysis of different samples of beef extract will vary, and the same is ecpially true of the results obtained by different operators. Furthermore, the results as expressed vary according to the method of assay emjilnycd, particularly as regards the interpretation placed upon the content of nitrogen. * * * We presume to suggest that the estimation of a total acidity of beef extracts as lactic acid will be regarded by analytical chemists a.s somewhat of an innovation. This is certainly calculated to work some injustice in the case of our beef extracts, inasmuch as fruit acids are incorporated through the use of the pineapiile juice em- ployed in the jirocess of manufacture. 12 MEAT EXTRACTS. May we ask, therefore, that you will incorporate in your final report some note to the effect that the total acids of the extract are calculated as lactic acid, and further- more a statement that "Juice of partially ripened pineapples is employed as a digestant in the manufacture of Mos()uera Beef Extract." The high percentage of acidity is probably therefore accounted for by the acidity of the pineapple juice. Comment hy authors. — The points raised as to method of stating acidity are ehici(hxted by table lieadings and context. James P. Smith and Company. No, 1.5978. We have not imported the article labeled "Maggi Bouillon" since November, 190G, as under the advice of your Dei)artment we changed the label .so that it read "Maggi Essence." It is not a food prcjduct in the general acceptation of the term, l)ut an essence which is added in very small quantities as an improver to insipid soups, weak liouillon, etc. John Wyeth and Brother. No. 159G5. In comparing the results of your analysis with the figures obtained iu our own labo- ratories, as well as with the analysis made some years since liy Dr. Fresenius, of Wies- baden, we are glad to say that in a general way the three analyses agree, particularly in view of the fact that doubtless the methods used in the different determinations have varied to some extent. The only appreciable difference we notice between your analysis and that of Fresenius is in the percentage of meat bases,'' which in his analysis is reported as 14.33 per cent as against your 5.99 per cent, but we find tliat this is due to a difference in the factor employed, that used Ijy Fresenius being ().25, while you have used the now generally accepted factor 3.12 in calculating the meat bases. We have ourselves determined the meat bases as amounting to 8.2(i per cent, by precipi- tating the total proteids with bromin, deducting the percentage of nitrogen which they contain from the total nitrogen and nuiltiplying the difference by the factor 3.12. MEAT EXTRACTS. Tentative Standards. The following standards were issued for criticism by the Committee on Food Standards of the Association of Official Agricultural Chemists, on November 19, 1906, but have never ])een uificially promulgated by the Department. SOLID MEAT EXTRACT. <■ 1. Meat extract is the product olitained liy extracting meat with boiling water and concentrating the li<|uid portion by evaporation after the removal of fat, and contains not less than seventy-five (75) per cent of total solids, of which not over twenty-seven a Acidity of sample No. 15976 given in Table IX: No. 15991 in Talile X. b See Table X, page 27. <^ Subsequent action by the Joint Committee on Food Standards, representing the Association of Official Agricultural Chemists and the Association of State and National Food and Dairy Departments has modified the standard to read "not less than 8 per cent is nitrogen," inserted the word " Fre.sh " before the word "Meat" in the first line, and added the words "and kreatinin" in the last line. These changes have not been officially promulgated. METHODS OF PREPARATION. 13 (27) per cent is ash and not over twelve (12) per cent is sodium chlorid (calculated from the total chlorin present), not over six-tenths (OJi) per cent is fat, and not less than seven (7) per cent is nitrogen. The nitrogenous compounds contain not less than forty (40) per cent of meat liases and not less than ten (10) per cent of kreatiu. KHIII MKAT K.XTHACT. 2. Fluid meat extract is identical with meat extract except that it is concentrated to a lower degree and contains not more than seventy-five (75) and not less than lifty (50) per cent of total solids. In connection witli these tentative staiulai'd.s, the foUowino; reciiii- sites for a meat extract given by Liohig" afe of interest: 1. A gooil extract shoidd contain nci albumin and no fat (the latter not al>ove 1.5 per cent>. 2. The water content should not exceed 21 per cent. 3. About 60 per cent should be soluble in 80 per cent alcohol. 4. The nitrogen content should run from 8.5 to 9.5 per cent. 5. The ash should vary from 15 to 25 per cent, which, besides a little sodium chlorid, consists principally of phosphates. MeTIKID.S ok PltEP.\R.\TlllN. Up to a few years ago the soii]i lifjiior obtained from meat which was parboileil in tiie process of prepaiing canned meat was entirely wasted, but this liquor is now extensively utilized in the manufacture of extracts and preparations of meat. In preparing canned meat pieces of meat are placeil in iron baskets which are suspended in large tanks containing cold water. Steam is admitted and tiie meat heated about one-half hour (thirty to forty minutes). The lifjuor, which is the source of meat extracts, is pumped into triple-eflect vacuum pans and heated at 160° F. for about four hours. Tlieii the solution is transferred to a single-effect finishing kettle and heated eight hours until the water content approximates 22 per cent. A first-grade extract of beef is prepared from beef alone anil is usually sold in jars. An extract of the trimmed bones, to which consideralile meat adheres, is also made. Tlic trimmings include odds and ends of meat, muscle tissue, bone, etc., and the product is a second-grade article. In preparing this extract the bones are heatetl, not boiled, for thirty to forty minutes, and the liquor evaporated to the consistencj' of extract. The extract prepared from corned beef liquor constitutes another second-grade product. This extract has a high content of nitrates and sodium chlorid. In addition there is an extract prepared from pork and other meats, sold under the gen- eral term of meat extract. Mixtures of the various meat ami bone extracts are often made. A fluid meat extract is usually a 50 per cent solution of a solid extract. «R6ttger, Lehrbmdi der Nahrungsmittel-< 'hemic, p. 135. 14 MEAT EXTRACTS. Assuming tliat bocf extract contains 21.7 per cent of water, tliere is obtained from 100 jroiinds of "soup liquor" 1.94 pounds of com- mercial meat extract." These figui'es are high, as thej^ are calcu latetl from the total solids present in soup liquor. The manufac- turers claim that 100 pounds of "soup liquor" will yield 1 pound of meat extract. In speaking of the preparation of meat extracts, Charles R. Valen- tine '' states that when raw meat is finely chopped and macerated in the same weight of cold distilled water and squeezed out, the water dissolves from 16 to 24 per cent of the weight of the dry flesh. If the water infusion is heated, the albumin of the flesh separates as a flocculent precipitate when the temperature of 133° F. is reached, and the red coloring matter of the blood, likewise albuminous, coagulates at 158° F. The infusion, or extract of flesh, from which the coagu- lated albumin has been strained, when evaporated at a gentle heat jjecomes darker in color. When it is dried there is obtained a browai, rather soft mass amounting to 12 or 13 per cent of the original flesh. Valentine says it is not claimed that extract of meat is a food, but that it contains the extractive matter and salts of a large quantity of beef and possesses certain medicinal and dietetic properties. From about 32 pounds of lean beef, free from fat and bone, equal to 8 ]iounds of dry meat and 24 pounds of water, 1 pound of true extract of beef can be made. A good extract should always have an acid reaction, its color should be a characteristic yellowish brown, and it should have an agreeable meat-like odor and taste. It should be entirely soluble in cold water, and free from albumin, fat, and gelatin. Solid Me.\t Extracts. The percentage of nitrogen with its distribution in the various nitrogenous bodies is given in Tables II and III and throws much ligiit on the quality of the extract. The meat products examined are divided into four classes, i. e., solid and fluid meat extracts, meat juices, based on the definitions of the standards committee, and miscellaneous pre])arations. Of the six solid meat extracts reported in Table II, several fall below the ilefruition in one or two points. They, nevertheless, closely adhere to them in most respects, the percentage of nitrogen present in the form of total meat bases and kreatinin nitrogen being sufliciently high. The figures in Table III are obtained by calculation from those in Table II, and represent the percentages of nitrogenous bodies present expressed both as ])er cent of total nitrogen and as per cent of sample. In order to obtain the nitrogenous bodies from the corresponding nitrogen figures the following factors were employed: For insoluble n IT. S. Dept. Agr., Bureau of ("hemistry. Bui. 13, Part 10, p. 1390. 6 J. Soc. Arts, 1897, 4 I a 6 CO ^1 goOOOt^-* WOJ gSBSgss T3 is a J r^ 0^ i^ io -J5 2_: ■5^ -H CO M 10 10 33 ^ ^ '£> n t- to •-> ^ g '-D oi CR >0 -"P 1-^ m 1=1 CD 3 n o g 03 i M tlIlP,-g,Oi tj 01 r- oi t^ Oi ^J w rH -* CN ci ci ■*: 10 .-1 01 Tf 00 -H ■i* CO ■* (M i-f (M to a, — 1 ^ 2gg2 H ao.a 5u cJ ci -^ ci ci CO -cAfi2.B ■-C ^ —1 1— — 1 10 (J »0 « -^ CO 10 C-l 5; 06 CO to 06 CO CO t, Cl M C* CO (N CO il ft, 01 M 01 M M ^ 6 CO >o 'O "O '-: '-0 » C ■M '5 •5 "o tn s a X 03 03 1 g ,03 '3 a Si 1 ei Per ct. 2.74 4.08 2.74 7.14 10.76 3.64 Meat bases other than kreatin, kreat- inin.and xanthin. Per cent. 31.64 29.22 29.50 34.55 32.88 35.71 Xanthin bases. Per cent. 5.21 .33 .52 1.83 6.82 7.58 Kreatin and kreat- jnin. Per cent. 11.92 12.57 9.79 16.78 12.27 18.08 gas Per cent. 48.77 42.12 39.82 53.16 51.97 61.37 (£0 Per cent. 21.51 29.55 24.80 22.09 16.52 21.57 i i Per cent. 22.60 22.16 26.37 12.79 15.45 12.54 Insoluble and eoagula- ble proteid. Per cent. 4.38 2.09 6.27 4.82 5.30 .87 Am- monia. Per ct. 0.24 .45 .26 .52 .86 .30 Meat bases other than kreatin, kreat- inin. and xanthin. e c^ ci Ti« t~ CO S t~^ OC t-^ CO t^ 1^ Xanthin bases. Per cent. 1.03 .08 .11 .30 1.22 1.41 Kreatin and kreat- inin. Per cent. 2.71 3.56 2.34 3.15 2.53 3.87 03 eS « gal Per cent. 11.11 11.92 9.52 9.98 10.70 13.14 g-1 Per ct. 9.81 16.75 11.88 8.31 6.81 9.25 si Per ct. 10.31 12. .50 12.63 4.81 6.38 5.38 Insoluble and coagula- ble proteid. Per cent. 2.00 1.19 3.00 1.81 2.19 .38 Per ct. 22.12 30.50 27.51 14.93 15.38 15.01 6 1 15867 15868 15869 16048 16049 16060 ANALYSIS OF FLUID MEAT EXTKACTS. 17 a I :;• P. 1 . .— o -c ■.-: i.-; "-c o t'^ I* o r- cc CO "T 1.1 Net weight. Grams. 105.7 68.0 69.7 03.5 73.7 102.2 127.4 Unde- ter- mined. Per ct. 9.75 8.12 15.12 12.14 0.60 2.04 3.54 Ether ex- tract. Per cl. 0.09 .23 .50 .04 .05 .06 .09 Cl Am- mo- nia. t; — p Ji ^^ p QC. CO Meat bases other than kreatin and xan- thin. Per ct. 1.05 1.40 1.37 1.37 1.79 .77 .04 |l| Per ct. 0.23 .26 .22 .17 .04 .09 .08 Kreatin and krent- inin. Per cl. 0.38 .20 .35 .48 .80 ..50 .20 Total meat bases. Perct. 1.60 1.92 1.94 2.02 2.63 1.30 .98 P. a) Per ct. 0.70 .47 .77 .74 .41 .89 .91 Per cl. 0. 34 .10 .10 .54 .44 .31 Insol- uble and coagu- lable pro- teid. *: -* -.o CO Cl t^ -^ 00 VO"^OC^-.. (Ki 1. LT) 1.13 Tr-.uv. None. 'I'ni«>. None. Trace. .75 Ainido Jjodies, 17091 170112 170U1 170U2 19766 19767 19785 197S6 197S7 Round beef, cold pressed Chuck beef, cold pressed Round beef pressed at 60°r Chuck beef pressed at eo'C Juice from beef chuck at 60° C Juice pressed from sirloin steak and water Juice extracted from sirloin steak by cold pressure Juice extracted from beef chuck by cold pressure Juiceextracted from beef chuck by cold pressure after 6 hours at 60°-100°C. 7.69 Per ct. 65.87 50.32 11.01 37.61 Per ct. 3. 45 Per ct. 7.69 6.32 Per ct. 15.87 16. 66 37.07 24. 77 16. 51 22. 03 29. 17 20. 93 33. 33 Per ct. I.(K) 1.81 4 Per ct. 8.56 6.13 ;. ih; ;. 3s !. 13 :. 13 Per ct. 1.03 .90 1.34 .84 .56 .81 .44 YEAST EXTUACTS. M.\NlIKA(.-TtIRE ANIJ I^SK OF YeAST ri!EI'ARATI(lNS. Yeast oil hydrolysis yiekls extractives wliich are similar to those obtained from meat. For many years yeast extracts have appeared on the market, especially in Germany, and have also been mixed with and used to adulterate meat extracts. Such products are now manu- factured in tliis country to a limited extent. The water extract or infusion of yeast, when evaporated in the open-kettle process, darkens and looks like an extract of meat. Caramel is sometimes addetl to further deepen the color. Wlien the process of evaporation is allowed to go too far, a bitter taste appears, wliich is due to the peptones formed, and it is claimed this may be removed by washing with water and dilute ammonia solution. In general the preparaticm of an extract of yeast is similar to that of an extract of meat. In an extract of yeast the liigher nitrogen forms are more abunilant than in meat extract. Two samples of yeast extract examined contained 5.68 and 5.67 per cent of total nitrogen. In regard to their stimulating effect and general action on the body the two extracts (meat and 3'east) are practically identical according to Wintgen,'' and their value as a proteitl sparer depends only in part on their nitrogen content. oAbs. Pharm. Ztg., 1905, jO:432. DETECTION OF YEAST EXTKAt'TS. 21 MuTHdDW OF DeTECTIdN. Searl "■ suggests as a method for detecting yeast products added to meat prejjaralions, that a sohition of the extract be boiled one or two minutes with a modified Feliling's sohition. In the presence oi yeast extract a bluish-white precipitate is obtained. Arnold and Mentzel '' claim that a slight bluisli-wliite precipitate is given even with pure meat extracts, but by experience an analyst learns to detect by this method the presence of about 20 per cent of yeast extract in meat prej)- arations. Micko<^ suggests the determination of kreatin and xanthin bodies as a means of determining the nature of the extract. Wintgen'' states that the iiltrate from the zinc sulphate precipitate obtained in the determination of albumoses is entirely clear in the case of meat extracts, but somewhat turbid with yeast extracts. Tliis he finds to be true even when the best S. & S. filter paper is employed. By this method the authors could detect fi'om 20 to 30 per cent of added seast extract. E. Baur and II. Barschall' have applied the colorimetric test, as out- lined by Folm, for kreatinin to meat and yeast extracts. They find no kreathi or kreatinin in yeast extracts and base a distinction between the two on ibis test. wSalkowski '' has studied the various carbohydrates of yeast and gives several tests for j'^east gum. The most reliable test is unquestionably the determination of la-eatm. A yeast extract contains no kreatin and in a typical meat extract there is foimd from 10 to 20 per cent of the total nitrogen in the form of la-eatin and la'catinhi. The distribution of the various xantlihi bases als(j is different in the two kinds of extracts; in meat extracts, according to Micko,'' xanthin and hy])oxanthin predominate, while in yeast extracts adenin and guanin predominate. Re.sukt op Tests. A test for yeast extracts consisting in boiling tlu^ samples for one or two minutes with an umnodifie(l Fehling's solution was tried. Four samj)les were tested with the following a^sidts: Color of prccii>il:i1(>. A. Meat i-xlracl Very deep viiilel, color. B. Yeast extrael Very deep griM-ii color. C. .'iO per cent yeanl and 51) per cent meal extract Intermediate colijr. D. 12-5 per cent yeast and 75 i)er cent meat extract Violet color, not as strung as A . This test is of value as a qualitative and a confirmatory test for yeast extracts in the presence of meat extracts. " Pharm. .T., 1903, 7/:51G and 7(W; 190!, 7.':S(i. *- Pharm. Zt-., 1904, 49:l'lli. <-Zts. Nahr. Genussm., 1902, .5:193; 1903, «:7S1. (iArch. Phann., 1904, i'.ii':537. <" Arb. kaiserl. Gesundheitsamte, 190(i, i'.;:.5(i2. /Per, d. ohem. fies., 1894, L»7:499, ;/Loc. cil. 22 MEAT EXTRACTS. The method of Searl for the detection of yeast extract by the use of a modified Felding's sohition was also tested. The method is as follows: Prepare a modified Fehling's sohition by dissolving 200 grains of copper sulphate and 250 grains of neutral taitrate of sodium in 4 ounces of water. Add to this 250 grains of sodium hydroxid dissolved in 4 ounces of water. Dissolve 10 grains of the sample to be examined in 1.5 ounces of water, add to this one-half volume of the above solution and boil for one or two minutes. With genuine meat e.xtract no precipitate is given. Wlien yeast extract is present a curdy, bluish-white precipitate is formed. Tills method was tested on a sample of meat extract, a yeast ex- tract, a 50 per cent .solution of yeast and meat extract, and a solution containing 20 per cent of yeast and SO per cent of meat extract. In the case of the meat extract a veiy fine precipitate was olitained. In the three cases where yeast extract was present a flocky,l)hush- white precipitate was formed. It is evident from these results that the presence of 20 per cent of yeast extract in meat mixtures may be detected by this method. Searl also gives a modification to be applied when doubtful results are obtained by the original method. In such cases 3 to grams (50 to 100 grains) of the sample are dissolved in from 4 to 8 cc (1 to 2 drams) of water. Alcohol is added to precipitate the proteid matter, the solution is thoroughly shaken, and filtered. The residue is dis- solved in 45 cc (1.5 ounces) of water, filtered if necessary, and the usual method applied. This modification was tried on 10 and 20 per cent mixtures of yeast extract, but the residts obtained were not satisfactoiy, and it is doul)tfid if less than 20 per cent of yeast extract can be detected in the presence of meat extract by this method. Another test is described by Wintgen," who claims that the zinc sulphate filtrate in the case of meat extracts is clear, ])ut with yeast extracts it is turbid. This was found to be the case, as the following results show: Zinc sulphato filtrate, A. Meat extract Clear. B. Yeast extract ClonMSO, 010, G13. MISCELLANEOUS PREPARATIONS. 25 products is far less luiinenms llian the solid and fluid extracts. The.se products consist largely, if not entirely, uf all)unio.ses and peptones 'm addition to some insolultle proteid matter. The amoiint of insoluble and coagulable proteids is relatively small in most of the samples examined and the balance of the nitrogen is distrilniteil between the proteoses, peptones, and meat bases. The relative amoimt of these nitrogenous bodies present depends on the method of manufacture and extent of the hydration to wliich they are sub- jected. The net weights, as well as the retail prices of the extracts purchased, are interesting and are gixcn in Tables II, IV and IX. Drsrr.Ksiox ni' I{k«i i.ts. In several of these pre])arations but a small amount of meat extrac- tives or bases is found. The amoimt of kreatin and krcatinin is negative in several cases, showing that the products in (|uestion were not made by the evaporation of an infusion of meat. The total nitrogen is extremely low in a numl)er of instances, falling to 0.42 per cent in sample 16044. The stinudating value of the aniido acids and the nutritive value of the higher forms of nitrogen must be exceedingly small in these cases. This same sample (l()(i44) contains 91.69 per cent of water and retails for $1 per l)ottle of 477 grams. Another sample, 1.59.S9, retailing for 60 cents a bottle of 179 grams, is evidently largely an artilicial product and on aj);ilying the method for the determination of organic phosphorus the sanijile did not appear to resemble a heef juice or extract. This sani])le contains but 2. .36 percent total nitrogen, of which only 8. SI percent is in the form of meat bases: krealinin is lacking, the insoluble resi- due is relatively large, and alcohol is ])res(>n(. 26 MEAT EXTRACTS. a, 5, H 5 -ft ■ft B g ■c .60 .76 .50 .50 1.00 .25 .60 .60 1.00 aj BO 2; "3 ^O'0t^01-V--rf c-i * ' 1 8 S S s IC •OiOO (j^c-j r-; ■ 'w •-< ^ ^^^:^S^S22SSSSS ggg " ^ 1 o . ^-§.-l.§ ^9 SS^SS3gESS?SS32S5^St2^ ci ci ci oi ^ M ^ t^C0OOO»0;3.-^00-V=g' ocoo wJoi'r^.-H t-^ T-( CO r-H C5 ■ ■ 6-* -^ [^ ^ -qi t^ oi -^ — 1 ci -H ec M « r^ lo ^ _ ^„ c^ Cl Cl t;RgSg-S2fc?!SS88S2SS3S a.SgsgSSSiJSSSSgSSK'*'" Id 1^' g IsliSSii iiigiSiii NITROGENOUS CONSTITUENTS. 27 1 ■fl o o fl 1 -5 o o E 2 Am- monia. ^ Cl ci CO CO Meat. bases other than kreatin, kreati- nin, and xanthin. al Xanthin leases. Per cent. 2.19 2.85 .64 .78 Kreatin and krc- atinin. Per cent. 7.76 9.07 7.41 8. 59 Total meat bases. Per cent. 37.44 34.34 37.80 33. 59 Pep- tones. Per cent. 19.90 11.39 31.03 14.00 Prote- oses. Per cent. 34.40 29.89 25. 03 46. 88 m Per cent. 5. .5(1 21.53 2.43 2.34 VI 1 M § £ i?. -^1 Per cl. 0.19 .19 .35 .05 Meat bases other than kreatin, kreati- nin. and xanthin. .^ ^ M f- t^ fi 6 O) (M 0> a. a l| Per cent. 0.3.5 .43 .14 .03 ■Sid S-0-.P Per cent. 1.44 1.59 l.Sl .34 Per cent. 0.93 0.02 9.24 1.34 Per ct. 7.38 4.00 1,5. 19 1.13 Per cl. 12. 75 10. .50 12. 25 3.75 Insolu- ble and coagula- ble proteids. Per cent. 2.06 - 7. .56 1.19 .19 Total prote- ids/' Per cl. 22.19 22.06 28. 63 .5. 07 1.5911 1.5963 15976 ICWO Cl Cl -^ CO c* iG r^ Cl CO c; Cl CO ci ass H ;3 -j: o Cl Cl ■1 CO Cl o ^ o o> cQ'-'la^c: a. c-i ■£> c/j lO --5 "^^ -^ -J- .-. r-. ,-, ^ '■*A 'A OJ » cc r^ Cl 05 X' >o oimo) f32 cooco cni- oc- Ot' §22ig5S^gS CO —< «CI ^ CO ■^lO coo .-H Cl Cl ci crci o o 5 =-■ ^ COCl ^ C3 ■^ COCI o CIGOOO C-i TT gC' ■^ ^OQi>i ■^ lO o r— S2g2 1" CO -H to :^^S2 oo '*CI r- CO CI c) CC — QCCO QC--i ^■;:= O r- cr. -H t-i coco 'a' o ooo .n '.a 3 o 28 meat extracts. Methods of analysis and their discussion. (_)iio of tlif i^rcat olistaclcs in the way "f a tliorc)u>;li uiul careful .study of jnoteids is the unsatisfactory condition of the analytical methods. Many of the variations in reaulfs wliich have apjieared are undoul)tedly (kie' to faidty methods. Another serious source of error in tliis line of woric lies in the fact that different methods are used by different analysts and the results are not comparable. For instance, copper oxid, phosphotungstic acid, tannic acid and salt, and other reagents, are used by various workers to precipitate the higher amido bodies and separate them from the simpler amido bodies. That the precipitating power of these reagents is not the same is well known. For determining acid and alkali albumins, insoluble proteid, and coagulable proteid, the methods give only ajjprnxinuite results, those for the determination of several of the individual bmlies, such as kreatin, kreatinin, and ammonia, bein'g in a much more satis- factory condition. PREPAKATION OF .SAMPLE. In the case of li(juid and scmilicjuid ])rc])arations the bottle should be thoroughly shaken and great care taken to see that the solution is complete. Pasty and solid extracts or powders should be removed from the container and thoroughly mixed before sampling. A very convenient method is to dissolve a weighed sample in a measured quantity of water and run tiiis out of a burette as needed. This solution siiould be kept cold and the determinations started without delay. MOISTITRE. Moisture was determined in tiie various j)re])arations examined by drying the sample over night in a water-jacketed drying oven. In the case of solid meat extracts approximately 'i grams of the sample were used, for iluid extracts, 10 to 12 grams, and for meat powilers, 2 gi'ams. ASH. The ash content of the commercial samples is seen to be surju'isingly iiigii in many cases. (See Tables II, IV, and IX.) This is du(> to the fact that sodium chlorid is present in meat extracts in varying and often excessive quantities. Especial attention is called to the large percentage of sodium chlorid ju'escnt in several of the sam|des exam- ined. The figures reported in the tables are obtained by calculating the total cidorin to sodium chlorid. The ash was tletermined by the olHcjal metliod " and the so(Hum cidorid in the ash by the following ])rocedure: Dissolve the ash sample with nitric acid and make iiji In Vdliimi' in a 20l)-cc llasl^. Use 20 per cent, or any convenient ali(iuot, for titration u illi sulpho-cyanid according to the Vdlhard method. «U. S. Dept. Agr., Burean of Chemistry, Bui. 107, p. 38. METIIUDS OF ANALYSIS. 29 I'rl-i-rnt. .. n.-.M) A small amount of soiliuiu chlorid is ])ri'sent in nu'at, anil as much as 12 per cent is permitted by the tentative standard for meat extract, but the presence of 25 to W per cent is excessive and should i)e regarded as an adulteration. From 0.8 to l.S per cent of meat is mineral matter, and calculated to water-free substance this amounts to from 2.3 to 7. -5 per cent . The average composition of the ash of meat, according to Konig," is as follows: r.T riMlt. Pnlat^siuin :57.()4 Sodium ID.M Calcium :-'.-)2 M:i<;iu'sium 'A.'S.i O.Kid nf irnn O.-t-l Jolly'' gives some vei'V interesting ligures sli binations of ])hos])horic acid found in the muscles and tendons of calves and oxen, and the nu'tabolism of the various mineral sails is fully discussed ])v Albu and Neul>ei-g.' The analyses of the ash of several samples of meat juic(^ ])re|)ari'd in (he laixiratory arei^iven in Table XI. T'hci.^plinric acid. . _ Sidpliuric aci/ liir iixli of iiHiit cxlmi-ts awl inisrilhnuoiis prfjiiirtilions. Phosphoric arid Sulphuric acid. Silica Cliloi'in I'rr ciMlt. . . ■■',(). .Ml . . 2. o:i . . 0. ,Sl 18152.. 18159.. 18101.. 18434.. 18435.. 18563.. 185S4.. 18023.. 18624.. 19398.. 19399. . 19401.. 19707.. 19818.. 184IX).. 18033.. 18036. . 19458.. 19400.- 194C5. . 19467. - 18629.. 18635. . 18637. . 19817. . 18877. . Chlo- rin as sodium chlo- rid. Per rrnt. 39.78 40.85 «3. 47 41. 39 S2. 13 34.22 53.23 75.27 33.64 32.65 46. 65 37. 61 12.78 12. 24 12.21 42.34 22.93 30.88 12. 21 49.97 57.17 47.33 54. 80 53.98 48.02 39.48 Composition of salt-free ash. Insol- uble mat- ter. Pit cent. 0.42 4. 06 .07 1.43 1.02 .74 8.02 9.05 2.74 9.97 3.01 29.38 6.38 1.70 .61 29.38 5.74 Ferric oxid. Prr eeiU. 1 35 11 .35 17 28 05 3.46 14 11 ■ "(V)" Cal- cium oxid. Per cent. 0.27 Trace. 1.42 Trace. 1.02 Trace. .20 Trace. Trace. .40 Trace. 3.72 Trace. Trace. .32 7.80 Trace. 9.33 .32 .04 Trace. .59 Trace. Trace. Trace. Trace. Mag- nesium oxid Per cent. 0.35 Trace. .47 .90 Trace. .17 .41 Trace. Trace. .5(i Trace. Trace. Trace. Trace. Trace. 16.82 .18 .95 Trace. .54 Trace. Trace. Trace. Trace. Trace. .17 Potas- sium oxid. Per cent. 53.44 40.81 50.31 40.92 27.59 45.53 64.70 40.30 .50.51 51. 30 49.07 39.01 42. S5 41.21 27.59 3.17 43.88 30.22 27.59 45.75 47.02 46 82 39.00 49.03 32. 42 34.90 Resid- ual so- dium oxid. Per cent. 7.31 6 20 6.52 13.97 8.47 6 37 in. 02 4.08 5.27 13. 24 10. 40 9.04 0.99 3.40 4. 76 6.03 0.99 4.94 5.23 18. 30 9.09 18.99 9. 22 7.72 Sul- phur tri- oxid. Per cent. 5.50 11.19 8.13 4.09 21. 94 2.19 2. 40 3.47 2. .55 5.44 1,5. 18 2. 59 2.90 1.81 10.30 3.48 5.30 1.81 3.70 10.60 2.50 4.51 2.33 6. 25 3.27 Phos- phoric acid (PiOi). Per cent. 23. 26 25. 60 24. 50 25.25 23. 84 23. 99 30. 08 29. 40 22. 30 24. 29 27. 09 20. 05 22. 70 20.75 26.37 .69 28.31 37.53 20.37 32.18 29.65 27.51 23.98 30. 05 24.53 16 Sfi Alkalin- ity (N/10 hydro- chloric acid). cc per IW gramfi. 79,71 (iO. 80 S.5. 90 2(i. 10 ,9.80 70. 13 03. 49 £0. 47 OS. 76 5.5.' 04 43.00 65. 91 107. 64 43.06 75.06 79.10 33.31 a Loc. Cit, d Present in small amount. c Present, METHODS OF ANALYSIS. 31 SEPAKATION OF ORGANIC AM) IXOR(iA\lC PIIOSPHOItUS. Tlie 10:1 ratio of total phosphoric acid to organic phospiioric acid suggested by Siegfried and Singewald " is not constant. This nietliod should be further investigatetl before applying it to all extracts anil food products in general. The high inorganic phosphoric acid con- tent in some cases might be explaine(l by tiie fact that jiliospliates may have been added, but \vc should hardly expect this in the case of organic phosphorus. The method of Siegfried and Singewald for the separation of the organic from the inorganic jihosphorus was aj)j)lie(l to meat extracts m the following manner: Dissolve an amount of the original sani])le corresponding to Id grams of the water-free material in water in a 'MH) <-i- flask. Athod is questionable as the filtrate in the majority of cases was cloudy, and sometimes the slow filtration renders the method extrtMucly te(lious. Aciorrv. In the average solid or pasty extract the lactic acid content varies from 4 to S per cent, and, as a rule, the extract showing the highest jihosphoric acid content likewise sliows the highest acidity. This is undoul)tedly due to the fact that some of the phosphoric acid is in the form of dihydrogen or acid phosphate, although the cliaracter of the acidity has not been deiinitely determined. The method employcHl for determining acidity consisted in adding tenth-normal sodium hydroxid to a dilute solution of (he meat extract in water luitil a drop remo\(Ml by means of a small capillary tube and tested oil a piece of litmus paper gives a- neutral reaction. The results are expressed in v\\]nr centimeters of tenth-normal sodimn hydroxid, also as per cent of lactic acid ])reseut. It is recog- nized that the acidity of meat extra(-ts is due to various causes, l)ut lactic acid is the predominating acid, and the results for acidity are usually expressed in the case of such products as per cent of lactic acid. ' (See Tables I, III, and IX.) «Zts. Xahr. (lenussra., 1905, lii:F,2l, 32 MEAT EXTliACTS. NITROGENOUS BODIES. (.'lasses of Nitkogenous Constituents and General Methods (jf Separation. It is believed that the proteids are made up of molecules of extreme complexity — hundreds of atoms of carbon, hydrogen, oxygen, and nitrogen — but the arrangement of these atoms and their number have not been tlefinitely determined. Various proteid substances are spoken of, for example, albumins and peptones, as pure chemical sidistances, but it is impossible at present to prepare two specimens of egg albumin exactly alike, and in the case of peptones even more difliculty is encountered. Because certain nitrogenous bodies give color reactions that are alike antl exhibit a few points in common, they are grouped together umler a definite term. It is not surpris- ing, therefore, that the methods for the separation of nitrogenous bocUes are far from satisfactory in many cases. Professor Mallet" says the following classes of the nitrogenous constituents of food arc commonly recognized as reipiiring separate consideration : 1. I'roteids proper (liy somr' lalled alluuiiiiiciicli^i, and their cldsely }('laU'(i deriva- tives, the proteuses and pei)tones. 2. Gelatinoids or collageiis, and allied .sulwtanees immediately deri\ed injru them, sueh as gelatin, ehondrin, ete. 3. Simpler amids, amido-acids, and allieil sub^taiiees, such as the asparagiu, glu- tamin, etc., of vegetable materials, and the "flesh bases'' (kreat'iii, Icreatinin, etc.) of animal origin. 4. Alkaloids, or anunediUe coniiiounds of well determined liasic character. 5. Ammonia and its salts. (!. Nitrates. To these, no doubt, should be added lecithin and analogous sidj- stances containing nitrogen, but closely allied to the fats. The average nitrogen content of the pasty or solid extracts usually varies from 6 to 9 i)er cent. The nitrogen in the so-called meat juices is subject to much greater lluctuation, depending largely on the con- tent of solids. Although a high nitrogen content is not a guarantee of the character or mode of manufacture of an extract, an average nitrogen content is desirable. All nitrogen determinations were made by T. C. Trescot. Several new determinations were applied to the analysis of meat ])roducts. These include the separation and estimation of the meat bases by a modification of the Schjerning tannin-salt method,'' the determination of kreatin and kreatinin by the colorimetric method of Folin,'^ the determination of xanthin bases by the method of Schitten- helin,'' the estimation of ammonia by the magnesium oxid method,'' " U. S. Dept. of Agi-., Bureau of Chemistry, Bui. .54, page 7. bj. Amer. Chem. Soc., 1906, 7„':1485. cZts. physiol. Chem., 1904, .il:223. dlJ. S. Dept. Agr., Bureau of Chemistry, Bui. 90, page 129. ""U. S. Dept. Agr., Bureau of Chemistry, Bui. 107, page 9. METHODS (IF ANALYSIS. 33 the iletenninatiiin of total plmsjiliorus by tlie peroxiil method," anil the separation of the ori;;anic from the inorganic phosphorus by the method of Sie<;fried and Singewald/' described under ash. Sodium clilorid was estimated by tlie Volhard methotl.'' The methods of the Association of Ofhcial Agricidtiiral Chemists were used in most cases.'' For tlie determination of total nitrojien, total meat bases, xanthin bases, and insoluble and coagulable pro- teids alicjuots of one solution of the sample were used. The pep- tones were determined by the tannin-salt jnethod' and the kreatinin-' bj' a modification of Folin's meth(jd (page '.]'.)). Many reagents have been used to separate the meat bases from the nitrogenous bodies of larger molecular weiglit. Phosphotungstic acid has been more widely employed than any of the otiiers, but is known to precipitate many of the diamido acids,' and its jiower to precipitate completely the peptones'' is not established. Mallet' states that the use of phospliotungstic acid as. a precipitant, fol- lowed by washing the precipitate with hot water, seems to effect a separation of all the simpler amidic sul:)stances from the ])roteids and proteid-like bodies, excepting only the ])eptones. Mallet cpiotes authority to show that the peptones are precipitated by tannic acid. The method was tried in tlie present investigation, but was discarded. Bromin has been suggested by Allen and Searle' as a reagent for separating the higher amido bodies from the lower aniido acids, but it has Ijcen found by Schjerning' and others to ])e unrelial)le. That tlie tannin-salt reagent makes an absolute separation is not claimed, but it seems to lie the best at jiresent available. Ix.SUIABLE .\MI ('c)AGULABLE I'UMTKIIiS. In Table XIII figures are given showing the amount of nitrogen present in the insoluble form as distinguished from that present in the coagulable form. This separation was made on seven extracts in- cluded in Table VH (miscellaneous preparations), which showed high coagulable nitrogen tigurea. The i)rovisional methoils ' of the Asso- aj. .\mer. Cheni. Soc, 1904, ^'6:1108. f-Zts. Xahr. Genussm., 1905,70:521. cLiebig's Annalen. 1878, 190: 1. <'r. S. Dept. Agr.. Bureau of Clienii.<5tn,', Bui. 107. < r. S. Dopt. Agi-., Bureau ni Ciiemistiy, Bui. 99, p. 182. -' .\11 kreatinin figiires refer to kreatinin and krealin estinialcil as kreatinin alter dehydration. Sllamniarsteu, Physiological Chemistry, 1904, ]i. 8(1. 'iU. S. Di-pt. Agr., Bureau of Chemistn-, Bui. 73, p. 92. ' U. .s. Dept. Agr., Bureau of Chemistry, Bui. 54, p. 21. 7 Analyst. 1897, ^:i:2bS. <■ Zts. anal. Cliem., 1900. .i'v company manufacturing l(i041. Talile VI. but an entirely dillerent product, as stated on laliel. 17887 5.81 1.13 .021 19.45 .36 Same brand as 15963, Table VI. Protecses .\xd Peptones. The following tentative standard for peptones has been framed by the standards committee: Peptones are products jjreparcd by the digesti(_)n uf proteid material liy means of enzymes or otherwise, and contain not less than ninety (90) per cent of proteoses and peptones. The proteoses and peptones are nitrogenous bodies of smaller molecular weight and greater solubility and diffusibility than the albumins. They are prepared fi-oin the albumins by the process of hydration. The peptones are lielow the proteoses in the process of hydrolysis. The distinction between the proteoses and peptones usually considered is that made by Kiihne," who defined the pro- teoses as nitrogenous bodies precipitated by ammonium sulphate, while the peptones are not proiijMtated by this reagent. These two bodies also differ in solubility and as to certain chemical reactions. The zinc sulphate method'' was employed for the determination of the proteo,ses. The peptones were precipitated together with the proteoses by the tannin-salt reagenf and the peptone figures ob- tained bv difference. aZts. Biol., 1S8C, -'2;-12;?. 6U. S. Dept. Agr.. Bureau of Chemistry. Bui. 107, p. 11.5. cU. S. Dept. .\gr., Bureau of Chemistry, Bui. !l!l. p. 1,S2. METHODS OF ANALYSIS. 35 In regard to the nutritive value of the alhuinoses ami peptones much uncertainty exists, but many investigators, as Munk," Deiters, ^ Zuntz,"" Pollitzer/ and others, have showai that pure aibumoses and peptones can replace proteid matter of ecjuivalent nitrogen content. The nature of the proteoses, as precipitated by saturating a sam- ple of Liebig's meat extract witli zinc sulphate, was lately investi- gated bj' Micko,*" who applie(l the Fisclu'r ester method to the pro- teoses. He identified the following amido bodies by tliis method: Glj'cocoli, leucin, isoleucin, alanin, amido valerianic acid, prolin (race- mic and active), asparaginic acid (ra<'emic and dextrorotatory), glu- taminic acid anhydrid, and phenylalanin. Xo xanthin or kreatin was found in the proteose precipitate. Gelatin, dexek.ki, iiisitrsion. The addition of gelatin to meat preparations has been practiced in the past. By this means the manufacturer increased or main- tained a certain nitrogen content, but supplied the nitrogen in a form lacking in stimulating effect and probably in nutritive v^alue. The buyer was consequently deprived of the characteristic essen- tials of a true meat product, although the nitrogen content was relatively high. In many cases only a small proportion of the added gelatin existed in the extract as sucli, as it was converted bj' a grad- ual process of hydration into gelatoses antl gelatin peptones. Wliile the methods for the separation of gelatin from proteid matter are far from satisfactory, it is a nnicli simpler process than the detec- tion of gelatoses and gelatin peptones and their separation from tiie idbumoses and peptones, no satisfactory method for the separation of these bodies being known. Some gelatin may be fornieil in the preparation of a high-grade extract of meat, although with proper j)recautions thei-e should be practically nt)ne present. When a .sufficient amount of gelatin is present it is readily detected by the setting (qualities of the extract after warming. The power of gelatinizing is only posses.sed by unal- tered gelatin; its dissociation products do not have this power. Micko-* has recently studied the gelatin cleavage products and finds that practically the same liodies are formed on hydrolysis as in the case of the aibumoses. In both cases glycocoU predominates. This investigator states that no gelatin is jjresent in Liebig's extract "Therap. Monatsh., June, 1888. Deulsc'he mcd. Wochcnschr.. 18S9. No. fi Von Noordcn's Bpilrage zuv Lehre ■\iini StnflVcchsol. 18!I2. p. 47. f .Vrch. gesam. Phy.siol., 1SS.5, ■17:'M3. 'ilhid., p. 301. f Zts. Nahr. Gcnussm.. 1907. ;.i:2-j3. /Ibid., p. 284. 36 MEAT EXTRACTS. but tlie soluble funns (glutiu and gelatoses) are present, l)eini; forineil by aetion of the lactic acid on the gelatin. The following tentative standard has been framed by the fond standards committee: Gelatin (edible gelatin) is the puritied, ilricil. iiioilnnius i)r(Hluc-t of the hydrnlysis. liy treatment with Ijoiling water, of certain tissues, as skin, hgaments. and hone.s, from sound animals, and contains not more than two (2) per cent of ash and not less than fifteen (15 1 per cent of nitrogen. i:.\rEI!IMEN'T.\L WORK UN .METHODS. Experiments were made to test tlie foUnwing gelatin methods: (1) the Stutzer ice-water alcohol method," modified by Bigelow;'' (2) theBeckmann' formaldehyde method: (3) the triclilor-acetic-acid method of Obermayer. '' The gelatin used in these experiments was a product of good quality used in ])repariiig culture media. With Millon's reagent it gave a faint pink reaction in the cold, and upon heating a red color developed, showing some proteid matter was present. This reaction shows the presence of tyrosin, and as pure gelatin contain.s no tyrosin, a small amount of proteitl must have been present as an impurity. The biuret test gave a faint reaction with the gelatin solution. The solution of gelatoses and gelatin peptones used was prepared by treating some of the gelatin with weak (3 or 4 ])er cent) hydro- chloric acid for I'oiu- days on the steam bath. This solution also gave the Millon and biuret tests. Neither the gelatin nor gelatose solutions showed signs of gelatinizing. The former was of 1.14 per cent and the latter of 0.64 per cent strength. The modified Stutzer method gives, in the case of pure gelatin solutions, a rough approximation of the amount present, the result,s showing that about 84 per cent are recovei'ed. With a solution of gelatoses and gelatin peptones, this methoil gives about 3.6 per cent of the nitrogen present as gelatin nitrogen. This may be due to a trace of gelatin in the gelatose solution. In the case of Witte's pep- tone 19 per cent of the total nitrogen aj^jiears as gelatin nitrogen according to the modified Stutzer method. It seems that the abso- lute alcohol precipitates a portion of the albumoses present in AVitte's peptone. In the case of the meat extract used, 3.7 per cent of the nitrogen is estimated as gelatin nitrogen by this method. Mixtures of gelatin with gelatoses, Witte's jjeptone, and meat extract were made in various combinations; also mixtures of the meat extract, Witte's peptone, and gelatose without gelatin. The results for gela- aZts. anal. Chem., 1895, 34:568. l\J. S. Dopt. Agr., Bureau of Chemistry, Bui. 107, p. 110. 'Analyst, 1895, 20:44. d Zts. anal. Chem., IS'JU, l"J : 114. METHODS dl' ANALYSIS. 37 tin were very irregular and iiiaccur'ali', and in all cases (inly a jxirtion i)f the gelatin added was reenvered. It is evident that the ]iresence of alhunioses and ])epf ones, as well as of geiatoses and gelatin jieptones, tends to dissolve tiie gelatin and give low results by this method. The BeckinaiHi formaldehyde method," together with some com- ments thereon, reads as follows: A method fur the estinuiJinn nf m-latin in meal extracts is liascd ii|"iii llic Ilui that fdruiaUlehydf cniiiliiiies with it to fnriu a iinufiisilile and insuhilili' cdmpuund — fornialiii-gelatiii. In order to render insohiiile I srrani of i,'elalin dissuUi'd in water abo\it two drops of the 10 ]ier cent .sohition in water of fornuddehydc ifornialim are added. The quantitj' re(|uired is so trirtinj; that its wei,t;ht may lie nei,dected. The presence of mucli free acid hinders the reaction, whicli. howe\er, talrimated in an ali(iuot part of a watery solution by means of acid. .\no(hcr portion is treated with formalin, steamed on the water bath, and, after l)oiling for a short time with water, the residue is collected in a Gooch crucible, dried at 11111° ('., anil uci<;hcd. After subtracting the amount of albumin |irevionsly foitnd. this gives the gelatin. The pciitoiie, etc., in the liltrate can be ])recipitated in the usual way. The method will be of use in milk analysis for detecliny adulteialion with an enndsion i.f Liclatin and fat. The results obtained by this methoil were not salisfaclorv, and eon- firm the results obtained by Stutzer. .Vll of the solutions were filtered hot. The gelatin does not seem to form tin insoluble formtiiin- gelatin as described by Beckntaim and the gelatin results were extremely low. In the case of meat extract and \Vitti>'s pejitone, some nitrogenous matter was precipitated by the formaldehyde, the latter giving quite a large preci])itate. When the gelatose solution was useil, practically no precipitate was obtaiiieil. ( )n mixtures of these various substances, eitlier alone or in the presence of gelatin, only incomplete results were obtaine(l. Obermayer agrees with liaal>e'' in stating that trichloracetic acid will precipitate albumin and albumin peptones and thus affords a separation from other ])ept()nes, such as gelatin pejjtones, which are only precipitated by this reagent in concentrated solution. The trichlor-acetic-acid method for precipitating gelatin as t)utlined l)y Obermayer is briefly as follows: Precipitate the solution with an excess of trichlor-acetic acid, and wash the precipitate with dilute sul])huric or hydrochloric acid. Thoroughly extract the precipitate with alcohol, then with ether, dry and weigh the precipitate. According to Obermayer, the albu- " Report of ThirteeiUh .\ssembly of Bavarian Chemists, 1S04. pp. lS-20. i'Zts. anal. Chem., 1S82. ^'1 : :iO:^. 38 MEAT EXTRACTS. mins and gelatin, as well as the albumin and gelatin peptones, are precipitated by this reagent. In an excess of the reagent the albumin peptones are soluble, while the gelatin peptones are not. A 10 per cent solution of trichloracetic acid was prepared and its action tested on the following nitrogenous bodies: (1) Gelatin; (2) a mixture of gelatoses and gelatin peptones; (3) Witte's peptone (albumose and peptone preparation) ; (4) meat extract. The results of the test are as follows: In the case of the gelatin sample ten drops of the reagent gave a slight precipitate, while the other three nitrogenous substances exam- ined gave no precipitate. An excess of the reagent gave a heavy white precipitate with gelatin and Witte's peptone, a smaller pre- cipitate in the case of the meat extract (the reaction being obscured by the ilark color of the solution), while the gelatose solution showed only a sUght turbidity. It is evident from these results that trichloracetic acid does not pre- cipitate the gelatoses, neither when a small amount nor when an excess of the reagent is used. The gelatoses are precipitated by the tannin salt reagent and it is possible that a method for estimating the gelatoses may be worked out on the basis of the trichloracetic acid reagent. ToTAi. Meat Ha.ses. The meat bases contain from 4t) to 60 per cent of the nitrogen in solid meat extracts, as is shown in Table III. In one of the poorest extracts examined, but 3.82 per cent of the total nitrogen is present in this form. The meat bases are (hvided into two general classes, the mono- and the di-amido acids. By the method of analysis employed, the meat bases are found in the liltrate from the tannin-salt ])recipitate. Some of the meat bases, for example, kreatin and kreatinin, and the hexon and xanthin bases are well defined chemical bodies that have been isolated and analyzed, but a considerable number of the nitro- genous bodies classed as total meat bases are of unknown constitution and are classed as imdetermined nitrogenous matter. Many new bodies have been foiuul in meat extract in recent years. Kutscher" has recently found the following nitrogenous bodies: Ignotin, methyl guanidin, carnonuiscarin, neosin, novain, and oblitin. Krimberg'' has demonstrated the presence of carnosin, carnatin, and methyl guanidin in flesh. Micko"^ applied Fischer's ester method to Liebig's extract anil foiuid alanin, leucin, and glycocoll in abund- ance. Xo amido valeric acid was found, and most of the aniido acids were left in a sirupy mass. «Zts. Nahr. Genussm., 1905, .?0:528. 6Zts. physiol. Chem., 1900, 4S •.4i2. c Zts. Nahr. Genussm., 1902, 5 :193. METHODS OF ANALYSIS. 39 Interniediad' Ix'tweea the pejjtoiu's ami the aniidu acids is a class of substances, recently described by Fischer," called peptids, which are divided into two classes, the dipeptids and the p()ly])ep- tids. The importance of Fischer's work can not be overestimated, as a lieginning has thus been made in the imjxirtant prolilem of deter- mininji' the construction of the proteid molecule. KrEATIN .\NI> KliEATININ. AI'PLK'ATIOX OF KREATININ' TEST TO MEAT EXTRACTS. Kreatin and kreatiuin are two amido bodies which characterize meat and therefore the\' are natural and essential constituents of meat preparations. The other meat, bases are important constitu- ents of an extract of beef, but occur in smaller amounts. As kreatin is the princijial amido botly found in meat, we expect to iind it, together with kreatinin, its dehydrated form, in still larger cjuantities in meat extracts. In several cases in which the extract acted suspiciously, no kreatin was found, and grave doubts exist as to the source of such products. True meat t^xtracts give high kreatin and kreatinin results, as well as high figures for meat bases. The estimation of the kreatiii and kreatinin is, therefore, a very important determination and of great value in determining artificial and imita- tion meat and yeast products, and in establishing the .source and purity of an extract of meat. The determination of kreatin and kreatinin was carried out a.s fol- lows: Use an ali(|Uot of the filtrate from the insolul)le and coagulable proteid determination, the amount depending on the character of the extract.'' The ali(jUot must contain sufficient total kreatinin, after dehydration of the kn^atin to kreatinin, to give a reading not far from S° on the scale of the Dubosc colorimeter after applying the colorimetric method as outlined by Folin'' for tlie estimation of krea- tinin in the urine. Heat this alicpiot with 5 cc of half-normal hvdro- chloric acid for three and a half hours on a steam bath under a rellux condenser. Neutralize the hydrochloric acid by the atldition of .5 cc of half-normal sodium hydroxiil, then add 1.5 cc of a saturated picric acid solution, and 5 cc of 10 per cent sodium hydroxid. Shake the solution and allow it to stand for live minutes; make u]) to 500 cc and compare the color with a half-normal solution of potas- sium bichromate in the Dubosc colorimeter. The half-normal bichromate solution when the scale is set at 8° corresponds to 10 mg of kreatinin and from this figure the amount of kreatinin in the ali- quot is readily calculated. " UntiTsurh\ingcii ulicr .Vmiudsauren. Pdlypc^ptidc uiid Pmlrinr nSOn-IOnO'i. r.crliii. 1!I(m;. f'.\.li(|Unt sliniild riiiicsiMii ajipri ixiiiuit I'l v (t.2 t;ram nl' a lil■^l rla^s, miIiiI lici-l ex i met. '• Zts. pliysinl. Chciii., liiOl, 4! ;223. 40 MEAT EXTRACTS. Definite amounts of kreatin and kreatinin were added to samples of meat extracts and practically the entire amounts added were recovered by this methotl. The color of the various extracts inter- fered slightly with the reaction and attempts were made to remove the color by i)recipitatino; with basic acetate of lead and pliospho- tungstic acid ami by filtering through animal charcoal. In all such cases, however, low results were ol)tained on testing the tiltrate for kreatinin. Consecjuently, in this work the kreatinin method was applied directly to the coagulable protcid filtrate and no allowance was made for the error due to the color. Since the method calls for a dilution to 5U0 cc and but 10 to 15 cc are used for the determination, this error is negligible. Grindley and Woods" have determined separately the kreatin and kreatinin content of several extracts of meat and found both present in varying amounts. It is necessary, therefore, to determine these two liodies separately when a careful study of the nitrogenous bodies of meat extract is made. Some later experiments in the Bureau of Chemistry have shown that three and one-half hours heating in a boiling water bath is necessary fur the complete conversion of kreatin into kreatinin. Benedict and Myers* have described a rapid method for the estimation of kreatin and kreatinin by conversion into kreatinin in an autoclave. This method reduces the time of dehydration of the kreatin to fifteen minutes. APPLICATION OF KREATININ TEST TO TANNIN-SALT FILTRATE. In view of the fact that a portion of the kreatin in a sample of meat extract is precipitated by the tannin-salt reagent ' the total kreatin and kreatinin in the filtrate from the tannin-salt precipi- tate is determined, as well as the total kreatinin in the extract, before adding the reagent. A more correct figure is accordingly obtained for the total meat bases by adding to the total meat bases figures the amount of total kreatinin precipitated by the tannin-salt reagent. In applying the Folin method to the filtrate of the tannin-salt pre- cipitate considerable difliculty was encountered. The tannin was removed by means of baryta and the barium with sulphmic acid. After neutralizing, the total kreatinin was determined in the usual manner. In the estimation of the peptones, correction must like- wi.se be made for the amount of kreatin and kreatinin precipitatetl by the tannin-salt reagent. Xanthin Bases. In addition to kreatin and kreatinin, a true meat extract or meat juice should contain small amounts of xanthin bases, including xanthin, hypo-xanthin, guanin, and adenin. These bodies are de- « .1. Bi1[S. 41 rivod from the nuclei of the cells, ami, conseijuently, in an extract that is prepared from fresh, unaltered hcef a certain amount of these bodies should be obtained together with the salts and other extractive matter. The determination of the xanthin bases is, therefore, of value in determining the origin of an alleged extract of meat. The xanthin base figures in the tables show a variety of residts, which is explained by the fact that in the preparation of the extract inider certain conditions of heat and pressure some of these bodies are i. fAriti. Hyg., 1SS4, J -.373. 44 MEAT EXTRACTS. tivc reactions showtnl in 6 cases a slight trace and in 8 cases a very strong reaction, indicating that the "hquor" from the parlxiihng of corned beef was used in tlieir preparation. (See jx 13.) UNDETERMINED MATTER. Under this head are included nonnitrogenous organic matter as well as glycerol and carbohydrates. Glycerol has been considered imder a separate caption. The amount of undetermined matter present depends on the mode of preparation of the extract; not niore than 10 per cent should be present in a meat extract. Inosite and various aniido acids, from which the nitrogen has been sjilit oft", also constitute a portion of the undetermined matter. Several of the samples which gave a high per cent of undetermined matter were tested f(n' starch, reducing sugar, and glycerol. The following (|ualitative results were obtained: Qualitative tests for starch, reducing sugar, and glycerol. Sample. Starch. Sugar. Glycerol. l.'jMlO Present None Present Present None None None None Trace Present... None None loOfili Present. 1.1977 Hi041 None. 1(.04S 1(1049 1 Present. The al})nmose and peptone products which are high in nndeter-- mincd matter, according to the tables, contain carbohydrates (starch and sugars). In the case of several of the ftuid meat extracts, or juices, and in one or two solid extracts, glycend is present. HISTORICAL NOTE ON NUTRITIVE VALUES. GELATIN. It has long been known that gelatin is present in various anioiuits in meat extracts. The collagen of the muscle on hydration yields gelatin, and if the hydration be carried far enough soluble gelatin, gelatoses, and gelatin peptones are found. Gelatin, while rich in nitrogen, is not capable of keeping the body in nitrogenous equilib- rium, since the nitrogen is not present in a form available to the body as in all true proteids. This has latel}' been explained by Kauff- mann " on the ground that the gelatin molecule is lacking in the tyrosin, cystin, and tryptophane groups and that h\ feetling these amido bodies with gelatin animals are kept in nitrogenous equilibrium. Kauffmaun states that one-fifth of the proteid of a ration can be replaced by gelatin, but when used in large proportions the body is 'Pfliiscr's .\rch., 190.5, 109 :440. NI'TRTTTVE VALI'ES. 45 not kept ill e(|iiilil>riuin. This was ilcnioiistratetl liy an ex])(>riiiicnt coiKhictod by the author on himself, and also on doirs. Manrini" has fed larntial energy were in the form of carbohydrates it was found to 'oe possible to supply (J.'] per cent of the total nitrogen in the form of gelatin nitrogen for a period of two days and maintain a daily retention of nitrogen of 0.71 gram. Exact knowledge of the nutritive value of gelatin had its beginning in the researches of Carl Voit,'' published in 1872. As early as 1S60 Voit and Bischoff'' had established experimentally the truth first perceived by Bonders,'' that gelatin reduces the proteid requirements of the l)ody: but they were of tlie opinion at this time that it could perform all the work of proteids and replace tluun entirely in tiie diet. After Voit' had shown that a part only of the nitrogenous excreta is ilerived from the jtroteids of the body tissue, a portion coming from the '"circulating" proteids, he again investigated the extent to which gelatin coidd be substituted for ])roteid, and reached the following conclusions: Gelatin exercises its sparine |i(iwer on tlie jimleid.s IkjIIi with l:iri,'c anil witli snuill quantities of prciteid (meat) fed at the same time, and with small quantities in much "Arch. d. Farmacol. speriin., IflOfi, .;: 309, ,337. bProe. Soe. Exper. Biol, and Med., 1904. ;.^:3S. cj. Physiol., 1891, 7i:23. dZts. physiol. Chem., 1904, .;j:8. fAmer. J. Physiol.. 1907, /,'/:2S7. /Zts. Biol., 1872, 5:297. ? Die Gesetze der Ernahriinff des Fleischfressers. l.eipzit;. l.%0. ''Die Nahningsstofte, Crefeld. 18.J3. 'Zts. Biol., 1869, 5:329. 4*1 MEAT EXTRACTS. higher degree than either fat or carbohydrates. It can be shown that large quantities ol gehvtin spare more pro teid from combustion than do small quantities; that, however, proteid is lost from the body even if with largo quantities of gelatin the greatest possible amount of fat be given. A direct laying-on of gelatin, either in the glutin-yielding tissues or in the proteid-forming tissues, is not possible, and it must therefore be assumed that when gelatin is formed in the body it is at the expense of proteid. Gela- tin, for this reason, is capable of replacing proteids of the food only in jjart." Voit made no special attempt to set the limits witliin which proteid may be so replaced, but gives for a large dog these figures: 168 grams of dry gelatin spared 84 grams of dry flesh.* The next investigation bearing on the comparative value of gelatin and proteid was that of Oerum,'' who placed a dog on a daily diet of meat, starch, butter, and meat extracts; he then replaced all of the meat with enough gelatin to maintain the same nitrogen supply. He records a considerable increase in the nitrogen of the urine in the latter case. Pollitzer,"' in the course of some experiments undertaken to prove that the products of proteid digestion are to be classed with the pro- teitls themselves, and not with the proteid-sparing foods merely, compared the eflfects of gelatin on the nitrogen output with those of horseflesh and its products of gastric digestion. He concludes that pejitone and liemialbumose (prepared by Kiihne's methods) have a nutritive value wliich is in "sharp contrast with the considerable loss of nitrogen which takes place after feeding an equivalent amount of gelatin." Ganz'' fed Paal's glutin-peptone and was able to cover more than half of the total nitrogen requirements therewith. Gerlach'' also pre- pared a "glutin-peptone," and found that it is a good "sparing agent," but is not of itself al)le to replace prc)teid. Munk s in a brief series of experiments attempted to find the "upper limit for the substitution of food proteiil with gelatin," and reached the conclusion that at lea-st half as much proteid must be fed as is destroyed by the animal in fasting, if nitrogen equilibrium is to be maintainetl. Kirchmann,'' m a very painstaking research with proteid-free gelatin, determined that the proteid destruction may be reduced under the influence of gelatin alone as much as 35 per cent, and that this maxinium effect is obtained when 62 per cent of the body's energy requirement is supplied by the gelatin. "Zts. Biol.. :S72, .s^297. 6 Ibid. i-' Nordiskt medicinskt Arkiv, 1879, vol. 11, reviewed by Hanimarsten in Maly's Jahresbericht fiir Thierchemie. 1879, .9: 308. 'I' Archiv gesam. Physiol., 1885, 37 : 301. f Quoted by lUrchmann. Zts. Biol., 1900, -;o:54. ./■ Die Peptone. Haml)urg and Leipzig, 1S91. g Archiv gesam. Physiol., 1894, oS : 309. >' Loc. cit. NUTBITIVE VALUES. 4 I KruminacluT," farrviiit; the wtirk beijun by Kirchmanii si ill further, found tliat when the entire energy requirement of the dog was covered by gelatin the total sparing was only 37.5 per cent of the fasting nitrogen. Applied to a man who.se energy recjuirenient is 2, .500 calories daily Krunnnacher calculates that if .5 per cent of his recjuirements were supplied in gelatin (i. e. about 33 grams of dried and purified gelatin), the proteid destruction in his body would be reduced from 70 grams to about 56 grams, or, in other words, the 33 grams of gelatin would replace 14 grams of proteid. Gregor* used gelatin in feeding infants in certain cases where excess of proteid was contraindicated, and concluded that with a diet containing 4.8 grams of nitrogen per day (of which ''nearly all" was gelatin X), not more than iialf as much nitrogen was lost from the Ixidy as in starvation. Braf prepared a gelatose, which he identifies by Chittenden's'' method as a deuterogelatose, and fed it to convalescent patients as a substitute for a portion of the proteid in their diets. Mancini"^ studied the nitrogen balance of five convalescents from tj'phoid fever, while giving '"large cpiantities" of gelatin. He observes a considerable retention of nitrogen, but doubts whether proteid nitrogen can be replaced by gelatin nitrogen. Kauffmann^ studied the replacing power of gelatin in a diet con- taining "only as much proteid (mainly casein) as is necessary with a sufKcient supply of energy for maintenance of the body's condition." He concludes from his experiments on dogs that not more than one- fifth of the proteid in such a diet can be replacetl by (pure) gelatin if nitrogen equilibrium is to be maintained. With one-fourth of the prcjteid nitrogen so replaced a small minus balance occurs. Kauff- mann's paper is concerned chiefly with the attempt to bring gelatin up to th(> full nutritive value of proteiil by adding to it the amido- aciils which it lacks, but which casein contains. Rona and Miiller," in attempting to confirm Kaulfmann's residts with gelatin, tyrosin, and tryptophan, found first "the smallest quantity of proteid nitrogen with which the animal could well get along," and then replaced one-fifth of this proteid (casein) with gelatin nitrogen. Their observation as regards the amoimt which would be replaced was quite in accord with Kaufl'mami's, for when gelatin was substituted for two-fifths of the casein there was a dis- tinct minus balance. «Zt.s. Biol., 1901, .^.':242. (i Centi-alblatt fiir inucre Medicin, 1901. .'? : 65. c Deutsche medicitiLsche Wochenschrift. 1902. p. 21. rfj. Physiol., 1891, 12:2i. <■ Reale .^ccademie dei Fisiocritiei di Sieni, 190-5, I7;(j()7. /.Vrchi\-gcsam. Physiol., 1905, 70.9:440. sZts. physiol. Chem., 1907, 50:263. 48 MEAT EXTRACTS. The conclusions reached by the various investigators may he sum- marized briefly as follows: Gelatin can replace proteid only in part (Voit, Oerum, Pollitzer); it has, however, a high proteid-sparing effect, whether fed alone (Kirchmann, Knnnmacher), or with other foods (Yoit, Oerum, I. Munk, Kaufl'mami, Rona and Midler) in infant feeding (Gregor), or in convalescence (Brat, Mancini); this proteid- sparing effect is exerted also by gelatin-peptones (Ganz, Gerlach) and gelatoses (Brat). MEAT EXTRACTS .VND JUICES. The various protein bodies and amido acids are so closely asso- ciated that it is impossible to produce amido acids without produc- ing albuminoses and peptones. Consequently, every commercial meat extract must consist partly of albuminoses, peptones, etc. The best extracts on the market to-day contain about 50 per cent of the total nitrogen m the form of meat base nitrogen. Wlien a meat preparation contains only a small amount of its nitrogen in the form of meat base nitrogen, the term "extract" seems to be no longer applicable. And it is evident that the product represents much less meat than an extract with .'SO per cent of its nitrogen in the form of meat base nitrogen, pro\dded the total nitrogen in both cases is apjjroximately ec[ual. Moreover, it is necessaiy to distinguish between a meat extract containing large amounts of stimulating amido acids and relatively small percentages of albumoses, peptones, and msoluble proteid matter, and an extract (or, more properly, a meat product) wliich consists largely of albumoses, peptones, and insoluble matter and relatively small amounts of amido acids. The food value of this last group of products is undoubtedly greater than that of the former group, but the}' should not be classed as extracts because of their different nature. The value of the amido bodies as food is uncertain, but at least they furnish energy to the body. It appears, therefore, that the value of meat extracts lies principally in their stim- ulating (jualities, the active principles of tea and coffee being on a similar liasis. The question of the nutritive value and relative worth of the vari- ous nitrogenous, constituents of meat preparations is a much-dis- cussed but unsettled problem. Beef juice prepared fi'om fresh beef by )>ressure and heating and used unchanged is an ideal product, containing the extractives as well as a large amount of nutritive material. As a commercial product, however, it is impracticable. The higher forms of nitrogen, insoluble proteids, alkali and acid albu- mins, and coagulable proteids, as well as the vmchanged proteids, are the most desirable forms for the healthy individual. The invalid may require partly digested proteids, such as proteoses and peptones. A large amount of nitrogen in this form should be avoided, as manj' rf KUTKITIVE VALUES. ■ 49 investigations have shown that (liarrlupa and other disorders follow the feeding of peptones. The stinuilating properties of the amido acids are most valuable in that they create an appetite and pi'epare the sj-stem for food. The scojje of this report will not permit of the exhaustive treat- ment of tills subject, but brief mention is made of the following con- tributions as indicative of the tendency of the results obtained: Biirgi" states that meat extracts are not foods, and that all mate- rial taken in this form is quickly eliminated. Only 4. .57 per cent of the nitiogen, 14.S.5 per cent of the carbon, and 17.55 per cent of the energy content is retained. According to Rubner' meat extracts, after they have served their purjiose of stimulating digestion, are eliminateil from the body as rajiidly as possible. W. H. Thompson'' has fed arginin to dogs and found \'i\m\ 37.(5 to 77 per cent in the urine; on injecting ai'ginin SL' ]K'r cent appeared in the urine. A part of the arginin nitrogen ajijieared in the vu'ine as ammonia. Yoit claims that the value of meat extracts lies in their flavor, which pro- motes the flow of the digestive juices. As the constituents of meat extracts are largely in a form ready for elimination, Rubner'^ holds that they have little food value. Pfeift'er, Einecke, and Schneider' have fed asparagin tii cows and report a favorable efl'ect on the milk antl its constituents, and W. Voltz*' claims asparagin can replace proteid without lowering the quality of the milk and that it acts as a proteid sparer in herbivura. In oumivora its proteid sparing power is small and it seems to have no such power in carnivora Imt rather increases proteid cleavag(\ In feeding experiments with mice on a zein ration Willcock and Hop- kins '' found that on adding tryptophane to the ration the lives of the mice were lengthened. Ilenriques and Hansen ' have maintainetl nitrogenous equilibrium on feeding hetero-albumose. Rubiier-' discus.ses the alcohol-soluble and alcohol-insolultle por- tions of fluid beef. The nutritive value of fluid beef is considered at length and the author concludes that if enough of such product for an entire ration were taken the cost would be enormous. The claim tjuit two teaspoonfids of fluid meat have a nutritive value equivalent to one and one-fourth pounds of cooked meat is deemed correct. Two ".\rch. Hysione. 1004, .07:1. ''Ibkl. p. 19. cj. Physiol.. 1905, .;;j:ll)(;. dStoffweehsel, 1882, p. 449. fZts. Biol., 188,3, 7.9:,343. /Mitt, landw. Inst, konigl. Univ. Broslau. UIO.'i, .;:179. ffFiihlingsIandw. Ztg., 190.5, .>; (2i:41; (,:i): 9(i. ''J. Physiol., 1906, 35: 88. iZts. physiol. Chem.. 1900, .;,v : ;S8;5, iZts, Biol., 1879. 7.5:4.85. 4:5689— Bill 1.11 4—08 4 50 MEAT EXTKACTS. • teaspoonfiils of lluiil meat weigh about 5'2 grainy and are ec^uivalent to 65 grams of pure meat free from fat and bones. Barker"^ recently published a thorough review of the question and has taken up several, new points. In normal man the aniido bodies do not appear in the urine to any extent; therefore, they must be of value, and the author believes they are synthesized into protein by the cells of the small intestine. W. Voltz'' claims that amido bodies of different chemical constitution produce varying effects on the nitrogen and caloric bal- ances of the body. The tightly bound NH„ groups, holding an inter- mediate position in the molecule, such as are found in glycocoll, tend to increase the nitrogen retention less than the carboxyl XH., groups, wliich are more easily separated from the molecule. The amids in an ordinary diet give more favorable results than when fed alone. On feeding various amids to dogs the author obtained favorable results. An unsigned article in the Pharmaceutische Zeitung'^ discusses the manufacture of meat extracts, and says that when meat (fat and bone free) is extracted with water by heating, the extract does not taste like the commercial meat extract, and is wMtish, but after continued heating over an open fire and the addition of 30 per cent of salt, the commercial product, a brown aromatic extract with a characteristic taste, is obtained. In preparing meat juice, 1 pound of meat cut up and pressed yields 60 to 100 grams of a red-colored juice. Evaporate this at 60° C. in a vacuum to one-tliird its bulk and a slightly red solution with a taste of meat, but no salty taste, is obtained — a product differing from the commercial article. It contains 30 per cent of coagidable nitrogen. If a little of the solid commercial meat extract is added, we have the commercial meat juice. This article is answered by L. Geret,"* who tells of the virtues of Liebig's extract. H. Otto*^ claims that meat extracts contain no nutriment, and that the fine odor and aroma of meat bouillon is destroyed in the commercial product. Tlie nutritive value of beef preparations is also discussed by Chit- tenden.^ Liebig's and Armour's extracts were analyzed and found to consist largely of soluble extractives and inorganic salts of muscle tissue. The nitrogen is liigh but not to any extent available for the body's use, and according to Kemmerlich an animal fed on extract of beef mil succumb cpiicker than an animal not fed at all. Extracts are useful on account of their stimulating and restorative value. The content of potash salts causes a cpiickened and stronger heart beat. An extract of beef is more like an alcoholic stimulant than a food. Meat juices such as Wyeth's and Valentine's, according to Chitten- den, have little food value, resembling dilute meat extracts. « British Med. .1., Oct. 27, 1907. 'I \hU\.. p. 31C. ftArch. ges. Physiol., 1906, i;.^;413. <■ Il.id., p. 350. :197. /M«l. News, 1891, 55:716. XT'TRITIVK VALUES. 51 Tlir cxplaiiatiuii of tlu^ oxidation of tlie various aiuiilo aciils in (lie Ijody is now generally referred tu the relative jxisition and nund)er of carl)on atoms in the side chains. Sehotten," Pohl,'' and Knoo])'' have investigated this point quite thoroughly. The extent to •which the administration of various aniido acids will maintain tiie nitrogen ec[iiilihrium was fh-st investigated by Loewi/ who showed that the end jiroducts of digestion which no longer gave the biuret reaction are still able to replace tiie albumins destroyed during metabolism. Abderhalden and Bergell '' liave shown tliat amido acids when given in moderate amounts (glycocoll up to o grams; alanin, :) grams; leucin, S grams; phenylalanin, 3 grams) are completely destroyed in the body. Stolte' injected various amido preparations into a rabbit and found an increased urea output in all cases. According to Alann » the first change which the amido acids undergo in the body is prob- ably that of oxidation. oxy-acid.s being formed as occurs in plants and in alcajitan-urea when tyrosin and phenylalanin are changed into homogentisinic acid. It is an open cjuestion whether the carl)on chain, after the splitting off of the nitrogen wiiich forms urea, breaks up still further or whether it is utihzed in the building up of otlier nonnitrogenous substances, such as carl>ohydrates and fats. Wohl- gemuth'' by feeding rabbits with the inactive or racemised mono- amido acids (such as tyrosin, leucin, aspartic acid, and glutaminic acid) found that the ina<'tive acids become dissociated during meta- l)olism in such a way that the component occurring normally in the body is oxidized as far as it can be assimilated while the abnormal component is excreted partly or completely in tlie urine. The occurrence of monoamido acids in the urine during normal and pathological conditions has been studietl by Abderhalden,' Ab- derhalden and Bergell,-' Ignatowski,'' Abderhalden anil Barker,' and Erben.'" Loewi and Xeuberg" have studied the diamins of the urine. vSince the tliscovery of the enzym erepsin in the intestine the idea is rather generally accepted that the ])roteid molecule is broken down in part, at least to the ammonia stage, and the ammonia and other groups are synthesized into the characteristic bod}' protein through the agency of the epithelial cells of the villi of the small intestine antl transported by tiie lym])ocytes through the blood stream to the tissues. " Zt.'i. physiol. Chem., 188;?, fl : 60. * Bcr. d. chem. Ges.. 190.5. -IS : 2064. i- Arc-li. expor. Patli. Pharm., 1S96, S7: 413. i Zt.-f. physiol. Chem., I!t03. .ig : 5.37. c Hofmeister's Beitrage, 1904, 6 : 150. J Ihid.. 1903. J9 : 9, 464. '' Arch, r-xper. Path. Pharm., 1902, 4S: 30;i t Iliid.. 1904. 42 : 371. ( Zts. physiol. Chem., 1903. 39 : 9. I Il)i(l.. 1904, 42 : 524. / Hc.t'meister's BeitrSgc. 1903, .', : 15. m Ihid., 1904, 4J : 320. a Ch./migtry of the Proteids. 1906. » Iliid., 1904, 43 : 355. 52 MEAT EXTRACTS. In a recent article on the physiological action of muscle extracts, J. G. Slade" states that muscle extracts were formerly supposed to represent the whole nutritive value of the meat, but recently all nutritive power has been denied them, and indeed, except for such traces of albumin, fat, or peptone as they may contain, it is difficult to see whence such food value would come. This author concludes that muscle extract has no stimulating effect upon man's central nervous system nor upon the power of performing physical work. If taken as a strong solution or in large amounts it is lia})le to cause piu'- gation. In moderate doses it stimulates the action of the heart. This is not due to kreatin, xanthin, or urates. The movement of the plain muscles throughout the body is increased, which is probably due to ornithin and novain. Muscle extract in 0.5 per cent solution ircreases the power of the voluntary muscle, in 0.1 per cent solution it has no effect U])on the efficiency of the muscle, and in 0.2 per cent solution this is decreased. Xanthin has an action corresponding to the first effect; that is, in saturated solution it increases the efficiency. Kreatin has no action on voluntary muscle. The effect of fatiguing a muscle before preparing an extract from it is to increase its extract- ives and increase the activity of the extract. If injected into ani- mals it causes great languor, prostration, and all the symptoms char- acteristic of fatigue. Muscle extract administered as "beef tea" acts as a moderate diuretic to men and other animals. The iliuresis is associated with vasodilatation of the kidney. Dr. O. Dornlikitii * discusses the preparation and comjxisition of various meat extracts, powders, and other preparations. Xutrose and milk casein products are considered. Dr. J. Price' gives a recipe for prejiaring home-nuide meat extract after the general plan of Liebig's original recipe. lie considers that meat extract or juice prepared as he describes it is highly nutritious. A. Brestowski"'' claims tiiat meat extracts possess no food value, l)ut on account of the meat bases, potassium phosphates, and their flavor they have value in increasing nuiscle activity and the secretion of the gastric juice. The food and therapeutic value of peptones is discussed. Pawlow ^ says that muscle extract is a stimvdant to an exhausted sys- tem and assists digestion. Pawlow has shown that muscle extracts are stomach stimulants and cause a flow of gastric juice. He fnund also that the individual extractives, such as kreatin and kreatinin, were a J. Physiol.. 1907. 3.5 (3): 163. bAerxtlicho Monatschrift, 1898, L>:49. c Philadelphia Polyclinic, 1894, p. 93. d Medicin.-Chir. Centrbl., 1893, :^S:Cb3. "■The Work of the Digestive Glands, 1897, translated from the Russian liy \V. H. Thompson, London, 1902. NUTRITIVE VALUES. 53 ineffectual, and coiicludeil lliat tlie specific substance causiny; the stimulation was not known. Brunton" makes the followinj,' statement in regard to the efl'ect of beef tea or beef essence: We find (inly tun fn-(|Ui'iitly thai Iwith (Idctcjrs and patients tliink that the strength is sure to l)e kept np if a sufficient ([nanlily of beef tea can only be got down; l)Ut this oljservation, I think, raises the question whether lieef tea may not very freqiunitly lie actually injurious, and whether the i)roducts of muscular waste which constitute the chief portion of \ieef tea or lieef essence may not under certain circumstances l^e act u- ally poisonous. Fi>r although there can be no douljt that beef tea is in many cases a most useful stimulant, one which we find it very hard, indeed, to do without, and which could hardly be replaced by any other, yet sometimes the administration of beef tea, like that of alcoholic stimulants, may be overdt)ne, and the patient weak- ened instead of strengthened. Mays'' asserts tliat beef tea is entitled to be called a nutrient because its action is the same as tiiatof milk, or a 2 per cent solution of ox blood. In a later jiaper'' he a.scribes this nutritive vahie to the kreatin and kreatinin ]>resent. Dr. Tjchinan'' discusses the action and the toxicity of meat extracts and concludes that Liebig's extract is not a heart juiiscin, but is rather an aid to the heart. Both in hciiith and in sicknesss as much of the extract can be used by the body as the stomach can stand. Home- made meat extracts contain more potash than ecpiivalent amounts of Liebig's extract. Dr. Carl Voit <■ gives a very able discu.ssion of meat prejiarations and considers them of great value as a condiment, but not as a food. Dr. N. G. Vis^' conducted a set of experiments on men, using a mixed diet, including beefsteak in the first period. For the beefsteak he substituted in the second period an equivalent amount of nitrogen in the form of sanatogen, a .sodium-casein-glycerol-phosphoric-acid compound. There was an increased excretion of nitrogen in both urine and feces in the second period. Frentzel and Toriyama^ in opi)osition to Rubner find that of the proteid-free extractive material of meat about two-thirds takes part in metabolism in that it furnishes energy to the body. Dr. Emil Biirgi'' has studied the question of the heat and energy value of meat and meat extractives in the ca.se of dogs. ITis results show that meat itself is a much more valuable soiave of energy than are the meat extractives. 3 The Practitioner, 1880, i.5:325. bThe Lancet, 1886, ^:510. clbid., 1887, 7:257. d Aerztliches Intelligenz, 1885, .)V::5]8. « Miinchener medic. Woclienschr.. bs!i7, -;.(:221. /Ibid., 1898, 4-5:257. ffAreh. Anat. Physiol., Physiol. Alit., illOl, \>. -lil!). ft Arch. Hyg., 1904, .57:1. 54 MEAT EXTKACTS. E. Kenimericli" inade a study of South American meat extracts and peptones, and di\ides the proteid bodies of these sul>staaces into three groups, depending; on their action in the presence of various per- centages of alcohol: (1) gelatin substances precipitated by 50 per cent alcohol; (2) albumoses precipitated l)y SO per cent alcohol; (3) the peptones remaining in solution. The extractives are also in solution with the peptones. The author suggests a separation basetl t>n the fact that the extractives and salts dialyze while tlie other boilies do not. Frentzel and Schreuer'' fed meat extracts to dogs and compared the results with those obtained when meat was fed. These authors believe that the prt>teid-free extractives of meat, to one-third of their total, take part in metabolism in that they produce heat and energy. Dr. J. Forster '^ discusses Valentine's meat juice, and con.siders it of no more value than Liebig's as a food — that is, it is of value as a condiment. Dr. II. Sentltner '' gives analyses of some 12 meat extracts and bouillon extracts. He considers the original Liebig process extract to be the best and cheapest. Many of the bouillons and juices are diluted meat extracts. Frentzel and Schreuer '^ have studied the calorific value of meats and meat meal. Dogs were used in the experiments. His results agree with Kubner's in showing that the calorific value of meat is higher than that of meat powders and extractives. Dr. Jung' in an article on meat extracts and peptones iliscusses the various constituents of these bodies and methods for separating the same. The author believes that large amounts of gelatin and gelatin hydration products are present in some extracts, being included under the term "proteid" since no method for separating gelatin and its hydration products from tlu' \'arious proteid bodies is known. CONCLISION. It is commonly assiuncd that jimtcids, gelatinoids, and the simpler amids have very diil'erent nutritive values, and, wliile all authorities would agree in assigning the liighest value to the first of these, there is prol)ably no small dilference of opinion as to the order in wliich the sec- ond and third should be rated. In considering such a riuestion, there should be separately taken into account relative digestibility or solu- oZts. physiol. Cliem., 1893, ;S:409. l> Bipdermann'.s Ccntrbl. Agr. Chem., 1902, J7:391. cZts. Biol., 1876, 72:475. dArch. Hyg., 1897, 6:253. fArA. Anat. Physiol.. 1901, p. 284. /Clicm. Ztg., 1900, ;.•■; : 732. XUTRITIVK VALUES. 55 bility, capability of midergoint!; osmotic absorption, and oxidizabilitv for the production of energy. At present, no definite numerical state- ment of the relative nutritive values of nitrogenous bodies of these three classes can be made. It seeius much to be fiesired that more extended experiments than have so far been recorded should be nuide upon living animals (as far as possilile ujjoii iiiiman beings) to deter- mine the utilization of Ijoth ilw g(>latinoids and the simpler amids. The latter no doubt undei'go oxidation to some extent in the aninud body, and produce some energy in conseciuence. It is probably true of these simpler amidic substances that umch larger ([uantities than analysis exhibits as constituents of the food consunu'd, or than analv- sis detects among the residue of food rejected from the body witliout having undergone complete oxidation, nuiy be constantly formed among the earlier ])roducts of the metabolism of the jiroteids, and aftcrwai-ds themselves undergo lint her cliange into tlie sim])ler and more stable forms of carbon dioxid, water, and urea. In the animal body the amido acids are acted upon in two ways; that is, they are converted into the corrt>sponding fixed acids or car- bonic acid is sj)lit off, leading to the formation of Brieger's diamins, or it is possible for l)oth of these jirocesses to tal aliiumin taken as food can or can not be absorbed in the form of albunioses, ]»ej)toni's, and peptids remains to be determined. Meat preparations of the sort included in this report are largely used l)y the sick and the young. Their use is recommended fre- quently by physicians who may not have taken the trouble to ascer- tain the true nutritive value of the j)roduct prescribed. It seems to be the general consensus of opini