.
Dec.,
T H E J O U R N A L OF I N D U S T R I A L A N D ENGINBERING C E E M I S T R Y
1917
and cold cream have been taken and are shown in Figs. I, I1 and 111. The writer believes that the wool fat substitute described in this paper will stand competition with wool fat and "Eucerin," both now and under normal conditions.
1125
Some physiologists claim t h a t these two properties reside in a single substance and t h a t the milk-curdling and protein-hydrolyzing activitie definite and distinct side chains of molecule; others claim t h a t the two properties are due t o two definite and distinct enzymes secreted by separate and distinct glands. The scarcity of the calf rennet, both in extract and powder forms, due t o the foreign situation, made it imperative t h a t a substitute be obtained if the cheesemaking industry were t o be perpetuated. It was natural to t u r n to pepsin from the hog stomach for such a substitute. The first experiments were somewhat disappointing. Our custom had been, in the assaying of the calf rennet,' to determine the amount of rennet necessary to curdle a definite quantity of sweet, unpasteurized milk in a definite period of time a t a definite temperature. When this same technique was applied t o the assay of pepsin for its rennetic power, it was found t h a t our results were not comparable. A pepsin solution which has a rennetic value of roo per cent by our arbitrary standard did not have a strength of so per cent when it was diluted $ 0 per cent with distilled water, and in
Fir 111-COLD CREAMX IW 80 to 90 Per Cent Cheaper than Hydrous Lanolin
A further investigation is under way t o determine the value in the preparation of a wool fat substitute, of ceryl alcohol, ClrHasOH, from Chinese wax a n d myricyl alcohol, CaoHslOH, from Carnauba wax. I n conclusion, due credit is hereby given t o Mr. Sol. Bernstem, who spent considerable time in performing experiments and assisting in general to bring this paper t o a successful issue.
as acid is an activator for the proteolytic power of pepsin, i t was natural to assume k of uniformity in our rennetic assays was
OTIIER RZPERENCES "Technology of Otlr and Fats." Lewkowitsch. 239. Allen's "Orgamc Aoalysrr ' 4th Ed , 479. JohrcsbniiniP 1862. 413 J . p w k l . Chsm.. 9. 121; 43, 148. Ann.. 191, 283; 83, 16. Ber.. 98. 3135: 99. 638. 1474:. 31.. 97. 1122. Apolh. Zdi.. 857. J . Soc Ckrm. I d . 11, 134; 16, 14.
ab,
action of the milk and t o adjust it t o a definite acid concentration. When this precaution results proved to be as comparable rennetic property of pepsin as for The technique observed now in pepsin for its milk coagulative p
HVCIISIADTEI LABoa*TORIES
227 Fnohit S ' f , NBW Yon= C i n
___ __
~
THE RENNETIC PROPERTIES OF PEPSIN By IIOWARD T Gn*sE% Recewcd Augurt 29, 1917
Physiological chemi5tries teach us t h a t the gas ric juice consists of hydrochloric acid, inorganic chlorides and phosphates, together with mucin and the enz pepsin, gastric lipase and gastric rennin. The theory as to the source of the proteolytic activi y and the milk-curdling property of the juice has not been explained satisfactorily so as to be acceptable t o all.
the acidity of the sweet, unpasteurized milk is brought t o o.zXg by the addition of q. s. pure lactic acid. To illustrate the above points, I have appended the following experiments. These experiments include t h e determinations of the E. M. F. and PH alues, as well as the acid titrations, of the sweet and djusted milk, together with the period of coagulation. EXPEBIMEN$ r-Tbe milk had developed a high of acidity before reaching the laboratory. The acidity 0.294 developed during a thunderstorm while the milk was held in the ice box.
1126
T H E J O U R N A L OF I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y SWEET(UNADJUSTED OR UNPASTEURIZED MILK) Date 1916 9/ 7
PH 5.277
Acidity Per cent 0.22
2 ............ 9/ 8
6.581
0.16
3 ............ 9/15
6.56
0.135
4 ............ 9/18
6.33
0.1425
9/19
6.49
0.1475
6............ 9/20
6.41
0.15
7 ............ 9/22
5.70
0.1525
8............ 10/ 2
6.3
0.14
............ 10/ 4 10............ 10/ 6
...
...
No. 1 ............
5
............
9
11
..........
0.13
10/20
0.145
R, 4415 No. 2 4416 No. 4 4893 4893 No. 1 4893 N o 2 5532 5528 X o . 2 5470 Elix. Pepsin 4468 Elix. Pepsin Elix. Pepsin Scale, No. 1 Eljx. 5446 Ell% 5447 5579 ;;xn 4i22 No. 6 4420 No. 3 5520 No. 7 No. 8 4420 No. 3 4422 No. 6 5808 No. 2 5627 5579 Sol. No. 1 No. 2 No. 3 No. 4 4420 No. 3 No. 4
EXPERIMEKT 2-This test illustrates the question of dilution. When t h e I : 10,000 pepsin was diluted with 7 parts milk sugar, it was apparently inert when tested on sweet milk of 0.16 per cent acidity, b u t when t h e same milk was brought t o an acid concentration of 0.19 per cent lactic acid t h e pepsin dilution was found t o test I/S as strong as the original. E X P E R I M E N T 3-In this assay the three scales were apparently inert in milk of 0.13 j per cent acidity, also one fluid drachm of the elixir failed t o coagulate one quart of milk. When t h e acidity of the milk was brought t o 0.17 per cent, coagulation readily took place.
Coag. 1 : 30,000 Strength Min. 1 : 3000 3.75 1 : 3000 2.75 1 : 10,000 0.9 2.8
1 : 3000 1 : 3000 1 : 3000 1 : 3000 1 : 3000 1 : 3000 1 1 1 1 1 1 1 1 1
: 3000
3000 3000 3000 3000 : 3000 : 3000 : 3000 : 3000 : : : :
1 : 3000
Inert Inert Inert Inert Inert 3.61 3.12 Inert Inert Inert 30 Inert Inert Inert Inert Inert Inert Inert 30 20 30 Inert Inert Inert Inert Inert Inert
Cpag. in Min. 3.75 2.0 0.5 1.5 4.0 1.75 2.0 1.25 2.0 1.5 1.0 0.75 2.75 3.5 1.5 8.25 6.25 1.25 1.0 2.25 2.5 1.0 1.0 14.5 6.5 9.25 Less than 1 Less than 1 Less than 1 Less than 1 1.75 2.25
Vol. 9 , No.
12
MILK ADJUSTED Acidity Per PH cent 0.294 ...
0.19
6.21
0.17
6.34
0.1975
5.857
0.205
6.04
0.2075
6.17
0.2075
5.784
0.19
5.5
0.20 0.20
...
0.18
enzyme of high curdling power with no proteolytic strength, and in t h e other a high proteolytic power with no coagulative strength leads me t o accept t h e theory t h a t these two activities are closely bound in a single molecule, and t h a t under t h e proper conditions of temperature, etc., it is only necessary for this large molecule (pepsin) t o come in contact with milk and acid, or protein and acid when t h e respective activities of milk coagulation or protein hydrolysis takes place. RESEARCH LABORATORY DIGESTIVE FBKIENTSCOMPANY DETROIT, MICHIGAN
STRENGTHS OF MIXTURES USED
+ +
Rx 4893 No. 1 = 1 part 4893 2 parts Milk Sugar 7 parts Milk Sugar Rx 4893 No. 2 = 1 part 4893 EXPS. 3, 4 AND 10. Elixir Pepsin = 1 h i d drachm contains 2.5 grs. 1 : 3000 Pepsin. EXP. 6. Rx 5580 = 1 part 1 : 10.000 Pepsin f 7 parts Milk Sugar. hxp. 11. Rx 4420 No. 4 = 1 part 4420 No. 3 4 parts Milk Sugar EXP. 2.
+
CONCLUSIONS
The foregoing experiments seem t o indicate t h a t t h e substance which gives t h e rennetic property t o pepsin is not t h e same substance which gives this property t o t h e calf rennin. It has been shown t h a t it is necessary t o activate the pepsin by means of acid before it shows its rennetic power in its proper degree. The adjustment of t h e milk t o a definite acid concentration also aids t h e coagulation b y calf rennet, b u t the great difference between pepsin and calf rennin in this respect is t h a t calf rennin never fails t o coagulate sweet milk or t o give comparable results upon dilution, while pepsin fails more often t h a n it produces coagulation on perfectly sweet milk. Another great difference is t h a t pepsin acts best on very ripe milk, even t o a n acidity of 0 . 2 per cent or more, while rennin is not favored b y such a high acid concentration. Considering t h e above facts, together with t h e additional notation t h a t in pepsin these two properties, t h e milk-curdling and proteid-hydrolyzing, have never been isolated, so t h a t we have i n t h e one case a n
A METHOD FOR THE DETERMINATION OF ALCOHOL By C. J. HAINESAND J. W. MARDEN Received June 21. 1917
The fact t h a t so many methods have been suggested for the determination of alcohol is indicative of much t o be desired in the speed and ease with which determinations can be made. The specific gravity method with which accurate results can be attained and which is most popular citnnot in general be applied t o liquids other than pure alcoholic solutions. This paper has been prepared suggesting a method which does not require in many cases t h e distillation necessary t o specific gravity determinations, in t h e hope t h a t t h e results may be of value in analytical chemistry. Frary' and others have observed t h a t potassium fluoride or potassium carbonate when added t o alcoholic solutions will cause t h e alcohol t o separate from t h e remainder of t h e solution, t h a t is, t h a t aqueous solutions of potassium fluoride or potassium carbonate are immiscible with alcohol. Frary has suggested a method based on these observations for t h e determination of ethyl alcohol b y the use of potassium fluoride. The method is t o add sufficient of the salt (carefully weighed out) t o a n alcoholic solution in a glass-stoppered cylinder t o cause t h e alcohol t o separate, add a n in1
"Studies in Chemistry, No. I." University of Minnesota, 1912.
