214
T H E JOURNAL OF IlYDUSTRIAL A N D ENGINEERING CHEMISTRY
a n d after correcting for filter paper, etc., by blank determinations, t h e difference found should be regarded a s albumin nitr0gen.l Evaporate t h e alcohol filtrate t o within I O cc., a d d j o cc. of distilled water, boil down t o 3 j cc., then a d d 1 5 cc. more of distilled water, allow t o cool t o room temperature a n d filter. Wash precipitate with cold distilled water. Owing t o t h e sticky nature of this material a n d t h e difficulty in transferring t h e same t o t h e filter paper, i t is not advisable t o make this determination. T h e resulting filtrate obtained in t h e gliadin separation is treated with sufficient phosphotungstic acid t o cause precipitation of t h e albumin filtered and washed with distilled water containing phosphotungstic acid. Nitrogen determinations in this precipitate should be corrected for by running blanks containing filter paper washed in phosphotungstic acid. The nitrogen obtained by difference is regarded as globulin nitrogen. The nitrogen found in the phosphotungstic acid precipitate filtrate when properly corrected for is considered amide nitrogen. The total nitrogen found as amide, globulin and albumin when deducted from t h e total salt-soluble nitrogen is gliadin nitrogen extracted in t h e I per cent salt solution. CONCLUSIONS
One per cent sodium chloride extracts from flour edestin, leucosin and gliadin. 2. The amount of gliadin extracted by I per cent sodium chloride solution approximately amounts t o about 29 per cent of t h e total proteids. 3. The amount of gliadin extracted by I O per cent sodium chloride solution approximately amounts t o about 5 per cent of t h e total proteids. 4. T h e gliadin nitrogen extracted b y solutions containing sodium chloride can be determined a n d corrected for in making edestin a n d leucosin nitrogen estimations of flour a n d its products. j. T h e amount of nitrogen bodies extracted with salt solutions a n d directly coagulated by heat varies with t h e concentration of t h e solvent. The I O per cent concentration givss higher results t h a n was found possible with a I per cent salt solution. 6 . T h e nitrogen bodies soluble in salt solution are partly‘ or wholly soluble in diluted alcohols varying with t h e concentration of t h e sodium chloride used. I.
WASHINGTON EXPERIMENTSTATION PULLMAN
AN INVESTIGATION OF THE PRESENCE OF FURFURAL IN CIDER VINEGAR
Since nothing on t h e subject could be found in t h e literature a n investigation was begun t o determine its presence in normal cider vinegars. The results seem t o warrant publication at, this time. Twenty-eight samples of cider vinegar of known purity were tested for furfural by t h e aniline acetate method as given by Leach.l Sineteen gave a positive test, nine being negative. These vinegars were made a t t h e laboratory and their history known. In addition t o these samples some farmers’ vinegars were tested with similar results. From these results it is seen t h a t furfural may be present normally in cider vinegars and its presence does not necessarily indicate added wood acetic acid. I n t h e Abstract Journal (7, 6 6 6 ) appeared a method by Ronnet for detecting added caramel in vinegar. This method is based upon t h e formation of furfural when sugar is heated in t h e process of making caramel, and makes use of t h e Fiehe resorcinol reagent.2 Since i t appears t h a t furfural is normally present in some cider vinegars, its presence can again be said not t o indicate adulteration from caramel. This test for caramel was applied t o the vinegars of known purity and in every case a n affirmative result was obtained. Four of the samples tested for caramel did not give a test for furfural upon distillation, b u t gave a very positive caramel test. This may be due t o decomposition of t h e sugar during t h e drying on t h e water bath. The water b a t h was carefully maintained a t a temperature below 70’ C. t o avoid this possible decomposition, so this fact adds t o t h e unreliability of the method. Caramel was added t o some of t h e vinegars, b u t t h e resulting tests were not different Erom those t o which none had been added. TABLE I h-o .
Variety
T h a t pure cider vinegar contains volatile reducing substances has been known for some time a n d several methods have been given* for eliminating these substances in order t o get t h e true amount of reducing sugars. The presence of furfural in these volatile reducing substances was discovered while doing routine vinegar analyses in t h e Kansas S t a t e Food Laboratory. 1 Globulin does not coagulate a t temperatures below 100’ C. (see “Proteins of Wheat Kernel,” Osborne, Carnegie issue, p. 116). 2 THISJOURNAL, 6, 845, 928.
Furfural
..
Winesap Pomace. hTeg. P o m a c e . . . . . . . . . . . . Neg. Jeneton.. . . . . . . . . . . Neg. Jeneton Pomace.. . . Keg. Jeneton., . . . . . . . . . ..Aff. Clayton.. . . . . . . . . . AB. Black Twig.. . . . . . . Aff. York Imperial.. Aff. Ben Davis., . . . . . . . Aff. Ben Davis Pomace.. Aff. Limbertwig. . . . . . . . 4 f f . Limbertwig Pomace. 4ff. Winter Greening.. . . Aff. York Imperial. . . . . . Aff. Winesap.. . . . . . . . . . Aff. Winesap Pomace.. .. hTeg.
PI P2 3 P3
6 7 8 9 10 P10 12 PI2 14 15 17 Pli
....
No.
Furfural
Variety
G a n o . . . . . . . . . . . . . . . Aff. Gano Pomace.. . . . . . Aff. Jeneton.. . . . . . . . . . . . Aff. Winesap., . . . . . . . . . . Neg. Jeneton.. . . . . . . . . . . . Neg. Roman B e a u t y . . . . . . Neg. Winesap.. . . . . . . . . . . Aff. Black Twig., . . . . . . . Aff. Missouri Pippin. f . . . Aff. Aff. Unknown.. Pomace of above , . Neg. 70284 Farmers’ Vinegar., . . Aff. Rotten apples.. . . . . . Neg. 70284A Farmers’ Vinegar. ... Neg. Farmers’ Vinegar.. . . Aff. 9373 5159 Farmers’ Vinegar., . . Neg. 18 P18 19 20 21 22 23 24 25 A
.........
.
TABLEI1 NO.
A 9
B y AGNES A. ANDERSON Received November 15, 1913
Vol. 6 , NO. 3
70284 5159 9373 70284A 21
Caramel Variety Unknown. . . . . . . . . . . . . . . . . . . Good test York Imperial.. . . . . . . . . . . . . Good test P o r k Imperial Caramel.. . Good test Farmers’ Vinegar . . . . . . . . . . Good test Farmers’ Vinegar.. . . . . . . . . . Good test Farmers’ Vinegar.. . . . . . . . . . Good test Rotten Apples.. . . . . . . . . . . . . . Good test Farmers’ Vinegar.. . . . . . . . . . . Good test Good test Jeneton . . . . . . . . . . . . . . . . . . . . .
+
Furfural test Aff. Aff.
....
Aff. Neg. Aff. Neg. hTeg. Neg.
T h e above tables give t h e results; duplicate determinations are not included since in every case t h e results checked. 1 2
Leach, “Food Inspection and Analysis,” p. 777. Bur. of Chem., Bull. 164, 15.
Mar., 1914
T H E J O C R N A L OF I N D U S T R I A L A N D ENGINEERING CHEMISTRY CONCLUSIOli
I. Pure cider vinegar may contain furfural as a natural constituent. I t s presence, therefore, cannot be taken as indicating added wood acetic acid. 11. Since cider vinegars may contain furfural, its presence cannot be taken as indicating added caramel. 111. Cider vinegars m a y give a test for caramel b y t h e Ronnet method without containing furfural or added caramel, hence t h e method is not reliable. STATE FOODLABORATORY, UNIVERSITY OB KANSAS
LAWRENCE
SOME ABNORMAL FACTORS OF SO-CALLED FARMERS’ t CIDER VINEGARS By
JOHN
C. DIGGS
Received S o v . 19, 1913
T h e following analyses were made of eighteen samples of vinegar which were entered in a n apple product exhibit of a n apple show held in Indiana. Instructions relative t o t h e exhibit were t o t h e effect t h a t only legal cider vinegars should be entered.
Pol. 200 mm. Lab. Intensity of color tube No. 7604 B M e d i u m . , . . . . . , . , , . . . . . . -1.8 7605 B L i g h t , . , , , . . . . . , . , . . . . . . . -1.6 7606 B Very light.. . . . . . . . . 7607 B 0.0 7608 B Very d a r k , . , , . , , . . , . , , . . 7609 B Very dark. . . . . , . , . . . . . . . 4- 1 . 4 7610 B h l e d i u m . , . . . . . . . . 0 0 7611 B D a r k . . . . . . . . . . . . . . . , , . . , - 0 , s 7612 B M e d i u m . , . , . . . . . . . , . . . . . + 0 . 4 7613 B M e d i u m . . . . . . . . . . . , . . . . . -0.4 7614 B Very dark. . . . , , . . . . . . . . . -0.6 7615 B M e d i u m . , , , . , . , . , . . . . , , . -1.2 7616 B M e d i u m . . . . . . . . . . . . , . . . . -1.4 7617 B M e d i u m . , , . . , . , . . . , . . . , , -1.4 7618 B D a r k . , . , . . . . . . , . , . . . . . . , -3.8 7619 B 7620 B 7621 B hlediurn.. . . . . . . . . . . . . . . . -2.2 Minimum , . . . . . . . , , , , , , , , . . . , + 4 . 0 M a x i m u m . . , , , , , . , . , , , , , , , , , -3.8 ~~
-
Average . . . . . . . . . . . . . . . . . . . . .
-0.64
The acid content varied from 1.5j t o 10.2 j grams per 100 cc. T h e higher acid samples are impossible figures and indicate t h e addition of acetic acid. The lower acid values indicate dilution with water or insufficient fermentation. The total solids range from 9.64 grams, a sample very high in sugar, t o 1.73 grams per I O O cc. I n one sample t h e sugars were as high as j.97 grams a n d in another as low as 0 . o j gram per I O O cc. The sample having j.97 grams of course has not been properly fermented-the alcohol fermentation having been arrested by t h e addition of vinegar. The highest non-sugar solid content was 5.06 grams per I O O cc. Such a factor is impossible from a n apple cider and has been caused b y t h e addition of some foreign material. Just why any one should wish t o make such a concoction is a puzzle. The highest alcohol value was 3 . 4 grams per I O O cc. Any alcohol value above 0.6 per cent indicated t h a t t h e fermentation was not as complete as i t should have been. T h e ash of all came within t h e limit of t h e law, the highest being 0.757, t h e lowest 0.265 gram per IOO cc. T h e alkalinity
ANALYSESOF VINEGARS Total sugars NonTotal as sugar Ash Acidity solids invert solids Alcohol 9.56 3.73 1.55 3.66 8.23 3.92 5.01 5.15 2.50 3.88 10.25 5.53 6.99 5.83 6.32 1.94 4.38 4.60 1.55 10.25 5.13
5.09 9.64 2.07 3.22 2.06 1.73 2 96 3.16 2.60 4.66 4.47 5.37 2.00 2.97 2.57 2.53 3.04 3 , 75 1.73 9.64
0.63 5.97 0.05 1.54 0.35 0.78 0.39 1.01 0.16 1.05 0.i5 0.31 0.28 0.59 0.69 0.34 1.15 1.26 0.05 5.97
3.53
0.96
-
4.46 3.67 2.02 1.68 1.71 0.95 1.57 2.15 2.44 3.61 3.72
DISCUSSIOPI’ O F A N A L Y S E S
Sol. PtOs
1.72 2.38 1.88 2.19 1.89 2.49 0.95 5.06
0.757 0.460 0.265 0.304 0,388 0.358 0,392 0.409 0,272 0.494 0.552 0.313 0.478 0,434 0.293 0.349 0.506 0.387 0,265 0.757
52 34 18 20 34 22 24 16 20 30 48 32 38 32 26 26 46 44 16 52
16.8 10.9 8.5 13.5 19.1 5.8 12.5 11.2 11.7 20.4 24.7 8.4 6.6 11.4 10.4 15.3 26.8 15.8 6.6 26.8
2.47
1.28
0,411
31
16.6
~
The variation of t h e factors was remarkable. M a n y of these can be explained only as t h e result of tampering -the addition of some foreign material, dilution with water, or both. The polarization in t h e zoo m m . t u b e ranged from V. T h e positive readings un+4.0° V. t o -3.8O doubtedly indicated t h e addition of sugar or glucose.
Alk. of ash
2.91 0.61 2.62 1.96 2.16 0.35 0.80 0.31 0.52 0.28 0.28 0.07 0.55 2.19 0.35 3.40 0.14 0.17 0.07 3.40
5.06
I n color t h e vinegars ranged from a pale yellow t o a reddish brown. T h e bouquets of a few were excellegt while in some they were practically t h a t of dilute acetic acid. I n general t h e methods of analysis were those given in Bulletin 137, Bureau of Chemistry, Dept. of Agriculture. The total sugars were determined b y inverting t h e solutions a n d determining t h e reducing sugars. Alkalinity of t h e ash is expressed i n cubic centimeters of N / I O acid for ash of I O O cc. sample. Phosphoric acid is expressed in milligrams of phosphoric acid in I O O cc. The other factors are in grams per I O O cc.
215
Insol. GlycerP205 ine 0.51 36.2 19.4 0.44 20.1 0.39 28.5 0.12 21.1 0.07 0.30 30.8 0.23 30.1 0.25 30.1 14.5 0.22 32.3 0.39 32.6 0.18 28.0 0.25 19.3 0.32 0.40 26.0 25.0 0.42 39.5 0.33 34.9 0.31 30.8 0.06 14.5 0.06 39.5 0.51 27.7
Lead acetate PPt. Medium Medium Light Light Light Light Medium Heavy Medium Heavy Heavy Light Medium Medium Light Heavy Heavy Heavy Heavy
.,
.
~
_
0.28,
....
Ash Non-sugars 1 : 5.9 1 : 7.Y 1 : 7.6 1 : 5.5 1 : 4.4 1 : 2.6 1 : 4.0 1 : 5.2 1 : 5.5 1 : 7.3 1 : 6.7 1 : 16.1 1 : 3.6 1 : 5.5 1 : 6.4 1 ’ 6.2 1 : 3.7 1 : 6.4 1 : 2.6 1 : 16.1
_ 1 :
-
6.1
of t h e ash varied from 16 t o jz cc. of t e n t h normal acid per I O O cc. sample. Eight samples were below 30 t h e legal minimum. T h e soluble phosphoric acid ranged from 6.6 mgs. t o 26.8 mgs. per I O O cc. Five samples were below I O mgs. per IOO cc., t h e legal standard. T h e glycerine content varied from 0.51 gram t o 0.06 gram per I O O cc. X fully fermented cider will contain not less t h a n 0.25 gram of glycerine a n d a sample containing less t h a n t h a t amount is not a t r u e cider vinegar. The ratio between t h e ash and non-sugars should be close t o I : 5. However, we find t h e ratio I : 16.1 for t h e highest a n d I : 2 . 6 as t h e lowest. From these analyses we would call Sample 7604 fraudulent. It contains 9 . j 6 grams of acetic acid and nearly three grams of alcohol per I O O cc., a n impossible condition. Sample 7605 is slightly low in acid b u t has nearly six grams of unfermented sugar, indicating incomplete alcoholic and acetic fermentation. The deficiencies of Samples 7606, 7607, 7611, 7613, 7619,
