Oct., 191 I
T H A J O U R N A L OF ]&DUSTRIAL A N D ENGINEERING C H E M I S T k Y .
was based on the acidity and specific gravitj. of the canned tomato juice. The formula used was as follows: One hundred per cent. minus (acidity minus "Ratio Yumber Two") = per cent. of water in canned tomatoes. The f o r m d a gave lower results-the range being from 0.08 per cent. to 2 . 3 4 per cent., but the general average was 0.5 per cent., or smaller, higher results being found by drying in the water oven, due perhaps to the changing of some of the solid material while in the process of dehydration in the water oven. 6. A small amount of mater was found added t o the canned tomatoes in the form of 3 solution of NaCl or common salt, the greatest U ~ I Z O M found ?I~ added being about j per ~ ( v z tnsutc~. . The amount of water in canned tomatoes of the correct acidity was found to be 90.44 per cent., in the case of tomatoes not cold-packed. In the case of tomatoes which were cold-packed, the acidity was, of course, a trifle lower (about I O cc. . Y / I o NaOH less for I O O cc. juice) and the amount o f water was found to be on the average about 95.23 tier cent, by water oven and b>*formula to be 94.03 1)er cent, The correct acidity was based on analyses o f about 66 varieties of t o ~ ~ i a t ~The s . acidity of caviled tomutoes should be higher and the water content lower, due to loss in sterilization. This, of course, is not the case so much in cold-packed tomatoes. j . Taking the foregoing summary into consideration, the inference one draws ,should be of importance to both the tomato packer and to the pure food official. First, there art. very few cans of tomatoes which come within the trade standard for "Standard" tomatoes, t o say nothing of the so-called "1st Quality" brands of tomatoes. I t can be readily seen from the average amount of tomatoes that is put up in a can, that packers are putting about one-half a can of tomatoes to about one-half a can of juice. Second, if the juice of the can of tomatoes falls below a specific gravity of 1.0130 a t room temperature, added water is sure to be present; and if the specific gravity of the juice, filtered through cheesecloth of 40 threads to the inch, falls below I . O Z O O a t room temperature, added water is suspected. Third, the acidity- of the canned tomato juice expressed in number of cc. of -Y,'Io NaOH should not fall below 5 0 cc. -V/'IO NaOH for 100 cc. of the canned tomato juice. If the acidity is less than this, added x a t e r is sure to be present; if the acidity of the canned tomato juice is less than 78 or 79 cc. -V/IO NaOH, added water is suspected. Fourth, since the annual pack of tomatoes in the United States is probably not less than I O , O O O , O O O cases, canned tomatoes are a n important article of food for us t o consider. Fifth, the amount of water shaken out of the tomatoes by transportation half way across the continent was practically one ounce, from the cans of tomatoes of the net weight of 33 ounces or a little over 3 per cent. by weight. AGRICULTURAL COLLEGE. FARGO. N. D.
747
C I D E R VINEGAR. B y FRANK E. MOTT. Received June 20, 191 1
The purpose of this article is to describe a method whereby certain forms of adulteration of cider vinegar, now being practiced by the vinegar manufacturer. may be detected. The method depends upon the relation between levulose and dextrose in pure cider vinegar, as cornputed from the percentage of reducing sugars. expressed as dextrose, and the polarization. degrees Ventzke, zoo mm. tube, z o o C. PART I. I t is now a common practice among vinegar manufacturers to compound and sell as cider vineg-ar a spurious article, made by adding t o the legitimate fermented product of pure apple juice, dilute H A C or H,O which contain as dissolved solid material about z per cent. of solids derived from boiled cider, or the evaporated extract from re-pressings, apple parings, shins, cores, etc. When a sufficient quantity of the the boiled cider or apple waste extract has been added to pure cider vinegar, the adulteration may be detected by the positive polarization a t z o o C., stable after inversion, as is shown by the analysis given in Table I : TABLEI .
Qi?
2 34
0.36
normal
R Sugars.
1.13
1 13
2rn
P206,mg.
7 3
14.3
1 21
Polarization. ov., 2 0 o c . ,
200 mm. tube.
+0 2
f0.2
Here the non-sugar solids are so low as to engender suspicion, but have been found equally as low in pure cider vinegar, and the other values, taken separately, excepting the polarization, are such as have also been found in pure cider vinegar. The ldarization alone shows specifically that the vinegar h a s been adulterated with foreign dextrorotary material. The manufacturer of adulterated cider vinegar can, however, seldom be caught in the manner cited in the preceding paragraph. He sees t o it that his illegitimate product keeps pace with the progress of the government chemist, and that i t continues to bear all the characteristics of pure cider vinegar as generally accepted. Such products, some made by the manufacturer of the spurious article mentioned in Table I , who stated that the article mentioned in Table I was an accident, are shown by the analyses given in Table I I : I
.
lABLK
11.
---2 50 2.30 2.67
0 3 2 (normall 0 . 7 2 8 0.733 0.33 "
2.i5
0.36 0..34
276 1
0 32
"
" "
0,688 0.682 0.6XX
14 2 12 0 I1 8 11 0 1l.i
References a t the end o f the paper.
< -'
P?Oi, my.
Polarization,
ov., 2 0 T . . 200 mm. tuhe.
7
8 8
1 ii
i 3 6 5 6.2 6.3
I 57
sec ( 1
10.0 --0 6
1.98 2.06
-0.2 --0.2
2.07
-02
1.
~ 0 . 0 -0 6 --0.2 - 0.2 4 . 2
748
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 .
The analyses given in Table I1 are fairly illustrative of many articles sold to-day as pure cider vinegar. Here every value, excepting the polarization of sample I , taken by itself, is such as has been found in cider vinegar of known purity, and the products have to be passed as conforming to the requirements of a “legitimate fermented product of pure apple juice.” These products were adulterated with applewaste extract. Later in this article will be shown a method for the detection of this form of adulteration, and the method will be applied t o the analyses given in Table 11. PART 11.
Oct.. 1911
scissa, and the maximum value for D so obtained is represented by the line shown in Table 111.’
T H E RELATION B E T W E E N LEVULOSE A N D DEXTROSE I X P U R E CIDER VINEGAR.
Essentially, the sugars naturally present in pure cider vinegar are levulose and dextrose: levulose, as such, and levulose and dextrose as invert sugar, resulting from the complete inversion of the sucrose originally present in the apple juice. C. A. Browne, Jr.; has shown that, in a mixture of levulose and dextrose, the *percentage of each sugar present may be computed from the polarization and the percentage of reducing sugar, expressed as dextrose. The formulae derived by Browne are best applicable t o the conditions under which they were derived, namely, solutions of pure sugars, but this article will show t h a t a practical application of the formulae may be made in the computation of the percentages of levulose and dextrose present in cider vinegar. The formulae derived by Browne in the abovementioned article are : 0.793 R - P I. Levulose (Lzo0)= 2.08
where IC equals per cent. of reducing sugars, as dextrose, and P is the polarization, degrees V., 20’ C., z o o mm. tube, on a basis of 26.048 grams in I O O cc. 11. Dextrose (D) = R - 0 . 9 1 5 L., R and 1, having the significances above mentioned. For the derivation of these formulae, reference is made to the previously cited article of Browne. In applying the formulae of Browne t o the computation of levulose and dextrose in cider vinegar, the author proceeds thus:
P =
p
X 26.048
total solids
where P equals the value to be substituted in formula I , and p equals the corrected polarization “V of vinegar, clarified with subacetate of lead, a t 2 0 ’ C. in a 2 0 0 mm. tube. R equals the per cent. of reducing sugars as dextrose ( I ) in the total solids, and is the value to be substituted for R in formulae I and 11. Making use of the above formulae, the percentages of L and D were calculated in all the reliable published analyses of cider vinegar of known purity,3 which give the necessary data for computation, t h a t the author is familiar with, and from the values so obtained D as ordinate was plotted against L as ab-
All the D values computed from reliable published and unpublished analyses of pure cider vinegar lie below this line of maximum value for D, from which i t was concluded t h a t whenever in analysis of cider vinegar a value for D is found in excess of the maximum value for D, as shown by the line in Table 111, t o correspond to the L value found by analysis, then foreign dextrorotary material is present. As a check upon the values, computed by the formulae of Browne, for L and D,- the following method was employed: From the fact t h a t in pure cider vinegar the percentage of L, as computed by the formulae of Browne, always exceeded the percentage of D, i t was reasoned t h a t a t 8 7 ” C., when a,L equals a,D, pure cider vinegar would be laevorotary, and the rotation measured, though influenced t o some extent by substances present other than L and D , could be used t o calculate, a t least approximately, the percentage of L in excess of the percentage of D. And that, vice versa, cider vinegar adulterated with applewaste extract, etc., in amount sufficient to bring the percentage of D in excess of t h a t of L, would a t 8 7 ” C. polarize to the right, though a t z o o C. it might to the left, and t h a t the polarization so measured could be used to compute approximately the percentage e x c e s of D over L. Table IV shows the experimental results so obtained: TABLEIV. Pure cider vinegar.
--.
Per cent. excess L over D by formulae of Browne.
Per cent. excess L over D calculated from polarization at 87’ C.
2.1 4.0 8.0 12.6
2.5 4.6 8.3 13 .O
Cider vinegar plus apple waste. A_____
Per cent. exPer cent. excess D over cess D over L by forL calculated mulae of from polarizaBrowne. tion at 87’ C. 7.4 7.3 3.6 3.2 2.7 2.3 1.5 1.8 0 . 0 Pol. ‘V. k O . 0 8 7 ° C .
I n preparing Table 111, the author noticed t h a t the ratios D/L as obtained from his own analyses were fairly constant, while the ratios obtained from the published analyses varied greatly, but a t the time he thought the variation a natural one. Later, in discussing this paper with H. c. Lythgoe, Analyst of the Mass. State Board of Health, mention was made of the influence of aldehydes on the reducing power of vinegar, thus opening a line of thought in pursuit
Oct., 1911
T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERIA'G CHEIZlISTRY.
of which the author observed t h a t the value for R sugars as obtained in his own analyses was by the method given under reference ( I ) , eliminating the aldehyde error, while the values for R sugars in the published analyses were obtained directly upon the vinegar b y the official method, and contained the aldehyde error. A comparison was then made between the percentage excess of L over D, in j samples of known-purity cider vinegar, as computed by the formulae of Browne, using the official method for R sugars containing the aldehyde error, and the percentage excess of L over D as computed from the polarization a t 8 7 ' C., zoo mm. tube. The results s n obtained appear in Table V : 'rABLE
Haldwin . . . . . . . . King . . . . . . . . . . . Greening., . . . . . . Russet., . . . . . . . . Mixed, pressing,
24.6 23.1 26.4 19.8 17 5
17.4 15.0 14 6 15 . 1 12 9
7.2
8.1 11.8 4.7 4 6
10.9 11.8 13.9 7.2 8.6
--0.5 -1.1 -1 .O -0.6 -0.5
--1.2 --1.9 -2.2 ---1 .2 --I 0
\'I
Computed by formulae of Browne.
Baldwin.. . . . . . . . King . . . . . . . . . . . . Greening . . . . . . . . . Russet. . . . . . . . . . . Mixed, p r e s s i n g , .
19.7 18.7 23.1 16.0 14.2
8 8 7.4
9.1 8.6 i 1
eliminated. Thus i t is concluded t h a t the proper relation between I, a n d D is obtained by thc usc of the formulae of Browne only when the value for I< substituted in the formulae is the value with the aldehyde error eliminated in some such way as in the method given under reference ( I . ) In Table VI1 is shown the line which represents the maximum value for D corresponding to any value of L. This line was obtained by plotting the values obtained by computing L and D in 2 0 different samples of known-purity cider vinegar, using the formulae of Browne and a value for R having the aldehyde error eliminated.
\'.
I n Table V, the discrepancy between the percentage excess of L over D, as computed by the formulae of Browne, and the percentage excess of L over D as estimated from the polarization a t 87' C . , is too great to be due to experimental error. Such a discrepancy would be produced by the substitution of too large a value for R in the formulae of Browne. A comparison was then made between the percentage excess of I, over D as calculated b y the formulae of Browne in the same 5 samples of cider vinegar as were used in preparing Table V, using, however, the value for R sugars obtained by the use of the method given under reference ( I ) , and the percentage excess of L over D as computed from the polarization a t 87' C., 2 0 0 mm. tube. This comparison appears in Table V I : TABLE
749
10.9 11.3 14.0 7.4 7.1
10 9 118 13.9 7 2 8.6
-0.5 -1.1
-1.0 -0.6 -0
5
-1 2 -1.9 -2.2 -1 . 2 -1 . O
The very satisfactory agreement between the percentage excess of L over D as computed by the formulae of Browne, using for R the value with the aldehyde error eliminated, and the percentage excess of 1, over D as computed from the polarization a t 87' C. is evident. The same good agreement is obvious in Table IV, where values for the excess of L over D by the formulae of Browne were calculated by substituting for R the value with the aldehyde error
In Table V I I , crosses indicate the results actuall:. obtained in analysis. Application o f the method employed in the coniputation of the values used in the plotting o f Table 1'11 vas then made to the analyses given in Table 11. Thc results s o obtained appear in Table V I I I : TABLE\TI I , Computed
11sthe formulae oi Browne. Per c e n l .
Per cent I. Per cent. D Per cent in total in total excess D solids. solids. over L. 11.1
15.5 10.8 10.4 10.4
19 . O 1 7 .8 15.9 15.3 15.3
7.9 2.3 5.1 4.9 4.9
excess J) over I*, from P. at87'C. 8.0 0.0 5.0 4.9 4.9
-----
I>,200 mni.
87'C.
2OoC
+0.6
*o.o
10.0 f0.4 +0.4 +0.4
-0.6 -0.2 -0.2 -0.2
In these samples it was then seen t h a t D was in considerable percentage excess over L and the adulteration with foreign dextrorotary material was apparent. The manufacturer of these vinegars admitted adulteration with so-called boiled cider. D I S C U S S I O N OF R E S U L T S .
The line plotted in Table I11 represents a n approximate relation between L and D in pure cider vinegar. That the relation thus represented is only approximate is shown b y the discrepancy between results for the percentage excess of L over D, as obtained by two different methods of calculation and given in Table V. That this discrepancy is due to the incorrect value for R, substituted in the formulae of Browne, is shown by the results given in Table VI. I n plotting the line given in Table 1'11, where the values for L and D were computed by the formulae
750
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 .
of Browne, using for I< a value with the aldehyde error eliminated, and checking the values so obtained b y calculation of the percentage excess of L over D from t h e polarization a t 8 7 ' C., i t is seen t h a t the grouping of results is far more uniform than in the plot in Table 111. Polarization a t 8 7 " C. cannot be recommended as a general method for the determination of the percentage excess of one sugar over another in cider vinegar. The reading a t 8 j O C. is frequently so close to zero t h a t the instrumental error is very great. All the readings a t 8 7 " C. given in this article are the average of 9 settings of the instrument. I n most cases the agreement between the two methods of calculation is fairly satisfactory, but in a t least one instance, No. 2 in Table V I I I , the agreement was far from satisfactory, the percentage excess of D over I, b y the formulae of Browne being 2 . 3 , while the average value of the polarization a t 8 7 " C. was & o . o for 9 settings of the instrument. It may, however, be stated very positively t h a t wherever an article, purporting t o be cider vinegar, polarizes to the right a t 87" C., then the article has been adulterated with foreign dextrorotary material. SUMMARY.
Assuming t h a t the sugars naturally present in pure cider vinegar are essentially levulose and dextrose : I . A relation exists between the levulose content and the dextrose content of pure cider vinegar. 2 . It is believed t h a t the line given in Table VI1 represents with reasonable precision the true relation between L and D in pure cider vinegar. This line is based upon 2 0 analyses of pure cider vinegar made b y the author. Computed from the reliable analyses of pure cider vinegar at present available, about 1 5 0 of which give the necessary data, if the aldehyde error be eliminated all the L and D values lie below this line. 3 . Whenever a cider vinegar polarizes t o the right a t 87' C . , sucrose being absent, the vinegar has been adulterated with foreign dextrorotary materials, usually dextrose. Cider vinegar may be adulterated with foreign dextrorotary material and, yet polarize t o the left a t 87" C. 4. Whenever a value for D is found in a cider vinegar in excess of the maximum value for D, as indicated b y Table V I I , t o correspond t o the value of L found b y analysis, the sample is not exclusively the fermented product of pure apple juice, b u t , sucrose being absent, has been adulterated with foreign dextrorotary material, usually dextrose. j. The method finally adopted b y the author for the determination of the relation between L and D in cider vinegar is as follows: Determine the absence of sucrose b y polarization before and after inversion. Total Solids.-Place IO cc. of the vinegar in a platinum dish, flat bottom, about 60 mm. in diameter, and evaporate t o dryness on a boiling water bath. Add 5 cc. water and again evaporate t o dryness. Again add 5 cc. water and evaporate, allowing the dish t o remain on the water bath about I hour after
'
Oct., 191 1
the final evaporation. Remove the dish; dry i t on a towel and place in a hot air oven a t rooo C. for 5 minutes. Place the dish in a desiccator, and, when cold, weigh, thus obtaining the total solids. Reducing Sugars.-Determine the reducing sugars as follows: To the total solids in the platinum dish add about 2 5 cc. of water and place on the water bath until the solids are dissolved. Rinse the contents of the dish into a I O O cc. graduated flask; cool, neutralize. and make u p t o the mark. I n the solution thus obtained, determine reducing sugars by using the Munson and Walker5 method on 5 0 cc. Express reducing sugars as dextrose. Polarization. -To 50 cc. of the vinegar add 5 cc. lead subacetate solution, 1 . 2 5 sp. gr., two teaspoonfuls of animal charcoal, of a lot, the applicability of which t o clarification for the purpose of polarization has been tested, and filter. Polarize in a zoo mm. tube a t 20' C., and express as degrees Ventzke. corrected. 0.793 R - P Calculation. x L = , where R is 2.08 the per cent. of reducing sugars, as dextrose, in the total solids, the aldehyde error eliminated. And
p
X 26.048
where p is the polarization of the total solids' vinegar as obtained under " Polarization " above. Finally, D = R - 0.915 L , R and L having the significances previously mentioned. I n conclusion, the author wishes t o express his appreciation of the kindness of Mr. H. C. Lythgoe, Analyst of the Mass. State Board of Health, and of Professor James 0.Jordan, Inspector of Milk t o the City of Boston. who criticized this article previous t o publication. P =
REFERESCES. I . Reducing sugars, expressed as dextrose, and determined a s given under ''5" in the Summary. 2. C. h.Browne, J r , J A m . Chem. SOC., 28, 439 (1906). 3. C. H Hickey, U . S . Dept. Agr.. Bur. of Chem., Bull. 122, p. 29. R . \V. Balcom. I b i d , 132, p 96. A . E. Leach and H . C. Lythgoe. J A m . C h e m S o c . , 26, 164 (1904). R. E. Doolittle, Report of Dairy and Food Commissioner of Michigan, 1904, p. 148. 4. T'alue for R used in computation of this plot was t h a t given in the
published analyses. Such values contain an aldehyde error, a n d in the results for L a n d D thus obtained are only approximate. 5 Munson and LValker, U . S. Dept. Agr., Bur.of Chem., Bwl1. 107. rev. 1909. B . 244
LABORATORY OF THE BUREAUO F MILK INSPECTION, HEALTHDEPART> T E N T . C I T Y O F BOSTON, 1 f A S S . . J u n e 7 . 1911.
LABORATORY STUDIES OF PEPSIN, PANCREATIN AND COMBINATIONS OF THESE FERMENTS. B y A. ZIMMERMAN. Received Aug. 28, 1911
Having for some time entertained the belief t h a t certain hitherto generally accepted statements relative to the pharmacology and therapeutic value of pepsin and pancreatin were erroneous, the writer decided t o conduct certain laboratory experiments t o determine, if possible, whether these statements should be accepted as scientifically correct. 1 R e a d before Division of Pharmaceutical Chemists, American Chemical Society. June Meeting.
