T H E J O l ' R N A L OF INDUSTRZ.4L AiVD EIYGZIVEERZ.VG CHEJ4lSTRY
998
It is shown t h a t in order t o obtain concordant results for iodine absorption a prescribed procedure nlust be followed exactly. T o obtain comparable results a standard procedure should be adopted in which the limits are more exactly defined than is true a t present. This is particularly necessary in t h e case of burnt linseed oils. TVith raw linseed oil a constant value is reached RTithin comparatively wide limits of weight of oil and excess of iodine. A study was made of the effect of temperature on the iodine absorption, from which i t would appear t h a t i t may be feasible t o improve t h e Hanus method by working a t lower temperatures t h a n those which have been used, and thus eliminate part of the substitution which occurs simultaneously with the addition. The results obtained show t h a t when used under exact conditionsthe Hanus method is t o be recommended for simplicity of preparation of the solutions employed, ease of manipulation, and for concordance of results obtained, Suggestions are made for the standardization of the method of determining the iodine number of mineral oils. The necessity for such action is shown by the results on several samples of lubricating oils. We wish t o express our appreciation of the courtesy of Messrs. Ault & Wiborg, of Cincinnati, in furnishing us with the burnt linseed oils used in this work. '
BUREAUOF
STANDARDS, WASHINGTON,
D. C.
EGG ALBUMIN IN BAKING POWDER By H. Lours JACKSON Received August 3, 1914
*
This paper is a summary of the results of three series of comparative baking tests, using different baking powders with and without egg albumin. They were carried out in the following bakeries in the city of Boise, Idaho: I-On cup cakes, during July and August, in the Home Bakery, and completed Sept. 4th, 1913. 2-On biscuits, April 23rd to hIay 15th, by t h e Shaeffer Baking Company. 3-On biscuits, June 78th t o June 24th, in the Imperial Bakery. Calculations for the last two were finished June 27th, 1914. I n all the bakings, the egg albumin added t o the powders was always Merck's "Albumin, Egg, Impalp. Powder Soluble;" it was added as described in Series 11. The cup cakes or biscuits were the bakers' regular commercial mixture. The ingredients, manipulation, time of baking, and all other factors were left t o his professional judgment and skill with the exceptions of the baking powder and the oven temperature. At the time of mixing t h e baker was furnished the proper amount of baking powder, weighed t o a tenth of a gram. Further details as t o the powders are given under each series. The temperature was t h a t regularly used in each bakery, except in the third series, when progressively lower temperatures were employed in order t o study the effects of unfavorable conditions.
v01. 6 , SO.1 2
High and low temperatures are defined as follolvr;s by A. J. Stephan, of the Imperial Bakery, the largest in the city: bread requires the highest temperature, baking best a t about j o o ' F. (260' c.);k 2 j 0 F. ( 2 1 s i / 3 0 c.) is the lowest possible for bread, as a t this ternperature i t dries out too much. The highest ternperature t h a t can be used is j 2 0 O F. (2;I.Io c,). Pies are baked a t 4jo'. t o ~OO' F. (232.2°-2600 c , ) . Cakes, according t o kind, a t 3 j o ' t o 450' F. (176.7-232.2' C . ) . Biscuits require for best reF. (2j4.4-260' C.!; 425' F. sults about 490-joo' (218.3' C.) is considered the lowest that should be used for biscuits, though they will bake poorly a t ~ o o O F . (204.4' C.). The temperature in the first series was not known, as the oven contained no thermometer. All products were judged by the bakers as soon as expedient after removal from the oven. The judgment of the bakers must be regarded as unbiased as, a t this writing, they are still ignorant of the manipulations t o which the baking powders were subjected. Products were weighed and measured as soon as they had cooled to room temperature, unless otherwise stated. A Bureau of Standards cylindrical brass liter was half filled with sifted rape seed (through 16),jarred in a uniform manner, the filling completed and jarred as before, filled t o overflowing and the excess struck off with a straight edge. The seeds were then poured into a tared vessel, weighed t o the nearest half gram in the first series, and to the nearest tenth of a gram in the second and third series. The cakes or biscuits were weighed in a like manner, weighing and measuring two, three, or four at a time, as two, three, or four could be introduced into the liter measure without touching each other. Cakes or biscuits were placed in the liter, one at a time, entirely surrounded by seed, and so on, until the vessel was filled, jarring i t in the same manner as before, every care being taken t o make this a very uniform procedure. The difference between the first and second weights of seed is t h a t displaced by t h e biscuits. The intent was t o make all measurements so numerous t h a t the unavoidable errors in measurement would be averaged out in the final result. The average weight of 1,000cc. of seed was found for each baking and is usually the average of ten weighings, though in the first series, three, five, six, eight and nine weighings were averaged together for different bakings. SERIES I
Cup cakes were chosen because in the estimation of the bakers they were best adapted t o experiment. The bakers knew this product so thoroughly t h a t they were confident they could detect any change in its appearance. A cream of tartar powder (Cleveland's) was used because it was the oqly one used in this bakery, and i t was not desired t o change the i n any way, as part of each baking nature of their cake m was t o supply t h e regular trade. Objection may be made t h a t fresh eggs were used as an ingredient in the cakes of t h e first series, but i t .
T H E J 0 U R ; V A L O F I N D U S T R I A L A N D EiYGINEERI,VG C H E M I S T R Y
Dec., 1914
must be remembered t h a t most products baked contain eggs, except i n baking powder biscuits. T h e method of calculation follows: 687.2 g. Av. wt. of 1,000 cc. seed. . . . . . . . . . . . . . . . . . . . . Seed weighed with cakes 1 and 2 . . . . . . . . . . . . . . 5 1 7 . 8 g . Seed displaced by cakes 1 and 2 . . . . . . . 1 6 9 . 4 g. 1.455 cc. 1 gram seed = ~ ~ ~ . .c. . c. . .. . ... . . . . . . . . . . . 169.4 R. seed X 1.455.. , . . , . . , , , . , , . , , , , , , . . 246.5 cc. 82.2 g. Wt. cakes 1 and 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . 246.5 . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.0 ~
~
”
~
”
~
~
’
*4v. specific volume of cakes
a n d z is 3. The cakes were weighed and measured two a t a time, constituting a group, a n d t h u s t h e average specific volume for t h a t group were obtained. All groups f o r a baking were t h e n averaged together in one figure a n d this alone is given. The mix in Series I consists of sugar, b u t t e r compound, eggs, milk, flour a n d lemon extract, all measured or weighed b y t h e baker as usual, except t h a t he took particular pains t o do everything as accurately a n d as uniformly as possible. T w o ounces of Cleveland’s baking powder went into each batch of five dozen cup cakes, which were baked i n five tins, holding twelve cakes each. T h e first batch was baked b y t h e time t h e second batch was ready, a n d t h e second was baked i n t h e same place in t h e oven as t h e first, t h e bakers striving for uniformity throughout. I n these large ovens t h e temperature changes very slowly, t h e oven baking uniformly for hours a t a time. The two batches were t h u s contained in t e n tins of a dozen each, a n d t h e cakes selected for measurement were t a k e n from each p a n in an arbitrary manner, so as t o avoid any conscious selection. About 30 per cent of t h e cakes baked were measured.
Average, . . . . . . . . . . (Weighted mean)
from t h e average because only t h e last five were baked, both with a n d without albumin, t h e average for those without egg albumin is still 3 . I I . Egg albumin was twice in t h e second batch baked, three times in t h e first baked. Bakings I a n d z were bought over t h e counter, before t h e firm knew t h e y were t o be tested. They serve as controls as do t h e two batches in Baking 3. JLJDGMEXTS-SERIES
I
TABLEI-AVERAGE SPECIFIC VOLUMEOF CUP CAKES-SERIES I No, With egg albumin of cakes 70albumin Without egg Baking No. averaged in parentheses albumin 1............. 12 .. 3.02 2............. 6 .. 2.99 17 .. 3,22-Batch A 3............. 3. . . . . . . . . . . . . 17 .. 3.10-Batch B 4............. 18 2 . 9 9 (0.5) 3.00 5............. 18 3.10 (1.0) 3 12 6............. 18 3.21 (2.0) 3.1, 7 . . ........... 20 2.99 (5.0) 3.06 8. . . . . . . . . . . . . 20 3 . 2 0 (20.0) 3.18 3.097 3.10
999
I
Bakings 3 and 4 were lost. Baking 5-In breaking three cakes of each batch, the texture of cakes A (without egg albumin) was a little, though a very little, better than B (with I per cent added albumin). Baking 6-B. cakes (without egg) judged the better mix. B. cakes thought to be slightly larger in volume. (This was not the case when measured.) Baking 7-B. cakes (without egg) a shade lighter in color than A . cakes. No other differences noticed between A and B cakes. Baking 8-Judgment lost. After studying t h e two batches i n every way possible, t h e final conclusion of t h e t w o bakers was about as follows: “Well, it’s p r e t t y h a r d t o say which is t h e better; t h e y are just about as nearly alike as they could be.” As t o t h e variables entering i n t o t h e work, t h e average weight of 1,000cc. of rape seed was determined for each baking a n d these averages h a d a maximum variation of I , 7 per cent. This is t h e smallest variable. T h e weights of cakes varied greatly. Commonly this was I O t o 1 5 per cent between t h e heaviest two a n d t h e lightest t w o in a n y bake. The weight of rape seed displaced b y cakes varied in about t h e same manner a n d indicated t h a t no large or constant error of measurement entered i n t o t h e series. These variations are best shown in Table 11. ’
TABLEI1
yo difference between
yo difference between h’umber of baking
max. and min. weights of cakes &
Sumber of baking
max. and min. weights of cakes I
.
3.108 3.11
The 94 cup cakes made with albumiiiized powder have a n a v . sp. vol. of 3 . I O ; 146 cup cakes made with non-albuminized powder have an a v . sp. vol. of 3 . I I. This advantage i n favor of non-albuminized powder is scarcely significant in view of t h e following facts: I n Baking 3, t w o batches designated A a n d B were baked, neither of which contained egg albumin in t h e powder used. This was t o ascertain what variation might occur when t h e t w o batches were identical i n every way, although t h e bakers thought t h a t different powders were being used. Batch A averaged 3 . 2 2 for 1 7 cakes. Batch B averaged 3 . I O for 1 7 cakes. This is a variation of 0 .1 2 in 3 . 2 2 a n d t h e largest in a n y one baking. 2.99 was t h e minimum sp. vol. a n d occurs three times, twice with egg albumin a n d once without; 3 . 2 2 is t h e maximum a n d occurs i n t h e series without t h e albumin; 3 . 2 1 a n d 3 . 20 occur with albumin. If t h e first three bakings are excluded
T h e most striking difference between Columns 2 a n d 3, in t h e same baking, is in t h e second baking. I n t h e original d a t a there is one weight of “ R a p e seed displaced by cakes,” t h a t looks quite suspicious. Casting out this weight, t h e final average in this baking is changed from 2.99 t o 2.96 a n d t h e “percentage difference” t o 6. Introducing t h e figure 2.96 into t h e final results changes t h e grand average for cakes without albumin from 3 . 1 0 8 4 t o 3 . 1 0 7 2 . I n other words, it does n o t change t h e final average a t all, for, when reported t o t h e correct number of places, we still have 3 . I I . This discussion of t h e errors gives a n idea of their magnitude a n d also shows t h a t t h e number of measurements has been large enough t o make even t h a t value which is most probably in error, without effect on t h e final average.
*
a
T H E JOURNAL OF I N D U S T R I A L A N D ENGINEERING CHEMISTRY
1000
CONCLUSIOK-SERIES
I
T h e addition of egg albumin t o t h e baking powder used i n baking cup cakes was entirely without a n y measurable result, a n d without a n y observable effect t h a t could be seen b y two experienced bakers. S E R I E S I1
I n t h e second series, another bakery did t h e work, biscuits were used, a n d temperatures a n d times of baking recorded. All biscuits in this series contained:
...
Flour.. . : ...................... 2 lbs. Baking powder.. . . . . . . . . . . . . . . . . . . 2 02. Compound (melted).. . . . . . . . . . . . . . . 3 level tablespoonfuls 1 level tablespoonful Salt,. 3 / 4 quart M i l k , . ............................
............................
T h e compound was added last. T h e poorest flour of which t h e baker knew was used in t h e first three bakings, because i t has been claimed t h a t a n albuminized powder shows t o greatest advantage with very weak flour. I n t h e fourth baking a strong flour was used. T h e baker controlled everything i n t h i s series except t h e baking p o y d e r which was K. C. Baking Powder. T h e t w o ounces were weighed t o a t e n t h of a gram a n d t h e n t o one portion was added t h e per cent of egg albumin shown in brackets in Table 111. T h e albumin was mixed into t h e powder b y rolling two hundred times on a rubber sheet in t h e manner used b y assayers in mixing powdered ores. The non-albuminized powder was rolled t o t h e same extent, t o expose i t t o t h e air i n like manner. T h e dough was rolled out between thin strips of wood upon which t h e rolling pin rested, t o secure a n even thickness of dough before t h e biscuits were c u t o u t . Dough left from t h e first cutting was discarded. T h e first batch was baked while t h e second was being prepared, t h e second t h e n went into t h e same place in t h e oven t h a t t h e first h a d occupied. Twice t h e egg albumin was in t h e first or A batch, twice i n t h e second or B batch. F o u r biscuits were uscally weighed a n d measured a t t h e same time, giving a specific volume f o r t h e group, a n d t h e specific volumes for t h e groups were averaged together (weighted if less t h a n four in a group) t o give t h e av. sp. vol. for t h a t baking. Table I11 shows t h e results: TABLE 111-AVERAGE SPECIFIC V O L U M E
OF
BISCUITS-SERIES 11
No. biscuits Time in baked average Minutes 29 11 31 13 24 11 21 13 11 12 13 12 17 12 19 12
Average sp. vol. % egg albumin Temp. of baking F. in brackets 498-500 2.64 (0.1) 500- 3 2.78 494- 5 2.67 (0.2) 495- 8 2.52 485- 7 2.62 487 2.52 (0.5) 489- 90 2.11 490- 7 2.28 (1.0) ' 85 biscuits with I of egg albumin . . 2.548 Average (weighted mean) ' 82 biscuits with2.550 ( O f out egg albumin
Baking. No. 1 A. ........ B......... 2 A ......... B ......... 3 A... B 4A B
...... ......... ......... .........
Bakings 2 , 3 a n d 4 set i n t h e pans t e n minutes before going i n t o t h e oven, a s certain companies making a n albuminized powder claim this t o be advantageous. Retaining three places i n t h e final result, t h e nonalbuminized powder gave biscuits with t h e same sp. vol. a s t h e albuminized powder, namely, 2 . 5 5 . T h e lightest biscuits ( 2 . 78) were without egg, t h e next lightest (2.67) with 0.2 per cent egg, t h e next lightest (2.64) with 0 .I per cent egg, t h e next lightest
Vol. 6, No.
12
(2.62) without egg. T h e lightest biscuit was baked t w o minutes longer t h a n i t should have been. JUDGMENTS-SERIES
I1
Baking I-Batch B slightly better than A ( 0 . I per cent) but very hard t o decide. Baking 2-Batch B is a little better than A ( 0 . 2 per cent) but both very nearly alike. [Assistant Baker: A (0.2 per cent) biscuits a little better than B.] Baking 3-Batch A slightly lighter by texture. B (0.5 per cent) raised a little higher (external appearance). Baking 4-Batch B ( I .o per cent) quite a bit better than A . These results are rather indecisive, for only in t h e fourth baking was a n y decided advantage recorded b y t h e baker's judgment. I n Baking 2 , t h e head baker a n d his assistant differed, t h u s showing no real difference between t h e two batches. I n Baking 3, Batch €3 was allowed t o s t a n d 1 3 ' / 2 minutes, before going into oven, instead of I O , as for A, through a mistake in watching t h e time. It was intended t o continue this series, b u t work h a d t o be stopped on account of other duties. S E R I E S I11
The third bakery (Imperial Bakery) did t h e baking a n d controlled all factors except baking powder, shortening a n d salt, which were weighed t o a t e n t h of a gram a n d supplied t o t h e baker a t time of mixing. A weak flour was used throughout. Mix used: Flour. . . . . . . . . . . . . . . . . . 3 Ibs.
..
Cottolene (cold). Salt. ...................... Milk ...................................
3 3
02.
02. I / % 02.
1 qt.
T h e flour, baking powder a n d salt were first mixed b y hand, t h e n t h e cottolene worked in b y h a n d , a n d last t h e milk added. T h e baking powders used were Crescent, manufactured with egg albumin a n d designated C ; K. C. powder, manufactured without egg; Atlas, manufactured without egg a n d designated A; Giant, manufactured without egg a n d designated G ; Interstate, manufactured without egg a n d designated I. All these powders are alum phosphate powders. Egg albumin was added t o p a r t of t h e nonegg powders in certain bakings in t h e same manner a s in Series 11. Bakings 4, j a n d 6 were divided i n t o t w o portions, designated 1st a n d and half. The 1st half was rolled out a n d baked about 9 A . M . T h e 2nd half stood in t h e proof closet until about 2 P . M . a n d was t h e n rolled o u t a n d baked. This was t o test t h e claim t h a t dough made with albuminized powder could s t a n d several hours, or over night, a n d still make good biscuits. T h e baker could not arrange a n y other time for t h e two bakings t h a n 8 . 3 0 A . M . a n d 2 . 0 0 P.M. T h e order of baking batches was t h a t given in Table 111. All dough was rolled t o a unif o r m thickness between narrow strips of wood, a n d t h a t left from t h e first cutting was discarded. T h e difference of 3 4 i n 2627 is 1.3 per cent, a n d is in favor of biscuits baked with albuminized powder. T h e greatest gains for powder with albumin are found i n t h e early p a r t of Series 111, when one brand of
powder, albuminized as i t comes o n t h e market, is directly compared with a non-egg powder a s manufactured. This is really unfair, a s t h e t w o powders used m a y differ i n their effects, aside from t h e egg albumin i n one of t h e m . T h e most striking failure of egg albumin t o improve a given powder is shown TABLEIV-AVERAGE SPGCIFICVOLUMEOF BISCUITS-SERIES No. averaged
Baking No.
4
A................. B................. c. . . . . . . . . . . . . . . . .
Time baked Min. 10 10 10 11 10 10 10 10 10 10
10 10 10 12 12 12 12 12 12 10 10 10 10
4 A 2nd h a l f . . . . . . . . . 5 A 1st half. . . . . . . . . . B 1st half C 1st h a l f . . . . . . . . . . 5 B 2nd h a l f . . . . . . . . C 2nd h a l f . . . . . . . . . 6 A 1st h a l f . . . . . . . . . . B 1st half .......... C 1st h a l f . . . . . . . . . . 6 A 2nd h a l f . . . . . . . . . B 2nd h a l f . . . . . . . . . C 2nd h a l f . .
..........
10
.......
10
Temp. baking O F .
495 495 470-1 47 1-4 465 465 465 450-5 455-60 460 458-60 458-60 458-60 430-5 430-5 430-5 443-5 443-5 443-5 45 5 455 455 460 460 460
111 Kind P e r cent sp. of egg vol. bk. Ddr. alb. 0.17 2.79 C. 0.0 K. C. 2.54 0.0 K. C. 2.60 0.17 C. 2.75 0.0 A. 2.71 0.17 C. 2.63 0.0 G. 2.53 0.0 G. 2.66 0.17 C. 2.63 0.0 A. 2.70 0.0 G. Lost 0.17 C. 2.20 0.0 A. 2.15 0.0 I. 2.96 0.2 I. 2.96 0.5 I. 2.90 0.0 I. 2.56 0.2 I. 2.54 n.... 5 I. 2.57 0.0 G. 2.65 0.2 G. 2.65 G. 1 .o 2.59 0.0 G. 2.27 0.2 G. 2.25 G. 1.0 2.26
Av.
Average (weighted mean) of 271 biscuits with egg. . . . . . 2 , 6 2 7 Average (weighted mean) of 238 biscuits without e g g . . . 2.593 Difference
.................................
__
2.63 2.59
0.034
i n Bakings j a n d 6, where t h e same powder was used first without egg, second with 0 . 2 per cent added egg, a n d t h i r d 0 . j per cent added egg i n Baking j. I n t h e first half, which was baked a t once, t h e sp. vol. fell from 2 . 9 6 with n o egg a n d with 0 . 2 per cent egg, t o 2. go with 0 . 5 per cent egg. I n Baking 6, 0.0 per c e n t , 0 . 2 per cent, a n d I . o per cent egg were present i n a second can of G i a n t powder. T h e s p . vol. fell from 2 . 6 5 with no egg, a n d 0 . 2 per cent t o 2 . jg with 1 . 0 per cent egg, a n d i n b o t h Bakings 5 a n d 6, these figures are t h e averages of 2 0 biscuits. RESULTS OF Temp. baking B a t c h 495 B
SUMMARY O F
Baking hTo. (1)
..........
( 3 ) , . . . . . . . . . 465
.
450-60
(4) 2nd h a l f . ,
458-60
(5) 1st h a l f . . .
430-35
.
443-45
.
455
(6) 2nd h a l f . .
460
(4) 1st half..
(5) 2nd half. (6) 1st half..
IO01
T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERING CHEMISTRY
Dec., 1914
C
B A C B A B
C
A C B A
c
B A
c
B A C
n
A
BAKINGTZSTS O N BISCUITS-SERIES 111 Bk. REMARKS pdr. 7*alb. K . C. 0.0 Better in looks, taste, odor (judgment of four persons) 0 . 1 7 Looks better t h a n A. (K. C . 0.007,) no difference in smell o r taste G. 0.0 Best C. 0 . 1 7 2nd A. 0.0 Poorest G. 0.0 Best C. 0 . 1 7 2nd A. 0.0 Poorest C. 0 . 1 7 Best G. 0.0 2nd A. 0.0 Very poor I. 0.5 Quite good I. 0.2 2nd I. 0.0 Very poor 0.5 Best I. 0.2 Poorest I. 2nd 0.0 Best G. 1 .o G. 2nd 0.2 G. 0.0 All good a n d all G. 1 .o G. 0.2 G. 0.0
J UD G M E NT
When biscuits a r e judged b y looks much greater differences a r e noted t h a n b y measurement. It appears t h a t a fine looking, large biscuit m a y have n o greater sp. vol. t h a n a smaller a n d poorer looking biscuit. This is due t o t h e fact t h a t t h e larger biscuit is heavier, a n d t h e sp. vol. works o u t a b o u t t h e
s a m e as for smaller biscuits. J u s t why t h i s is so h a s not been determined. This difference i n judging b y looks a n d measurement is strikingly shown i n Baking I , when batch B (0.0 per cent) was given t h e preference i n looks, t a s t e a n d odor, b y four bakers, separately, although A (C. 0 . 1 7 per cent) proved t o be larger i n s p . vol. b y o . 2 j i n 2.79. I n Bakings 4, j a n d 6 t h e bakers awarded t h e honors very uniformly t o t h e biscuits baked with albuminized powder. T h e differences were so marked t h a t anyone could n o t fail t o see t h e m , y e t , these differences do not show in t h e sp. vol. These were all baked a t too low a temperature, a n d t h e 2nd half of a bake was always carried o u t after t h e dough h a d s t o o d a b o u t five hours.
c 0 pic I. u s 10 N It is t h e opinion of t h e writer t h a t when bakings are carried out under normal conditions his work has not demonstrated t h e usefulness of egg albumin in baking powder, a n d especially in t h e very small q u a n t i t y usually present, i. e . , from 0 . I t o 0 . 2 of one per cent. W h e n t h e temperature of t h e oven is too low for baking biscuits properly, egg albumin seems t o aid i n producing a better biscuit. W h e n t h e dough is allowed t o s t a n d several hours before baking, a m u c h better biscuit is produced b y t h e powder t o which egg albumin has been added. OFFICE
THE STATE CHEMIST BOISE, I D A H O
OF
IRON IN TOMATOES By C. A. BRAUTLECHT AND G. CRAWFORD Received September 5, 1914
Tomatoes have become of much importance a s a garden vegetable during t h e last decade a n d present evidence indicates t h a t t h e y will become of greater importance. F r o m t h e view-point of t h e food, physiological a n d agricultural chemist more knowledge of their chemical composition is therefore desirable. Tomatoes are used as a food i n m a n y ways. While fresh, t h e y are e a t e n raw or cooked; tremendous quantities are canned; t h e y form t h e basis of m a n y soups; large quantities of tomatoes, or their products, are used as sauces for meat or fish foods; i n desert regions, or where good drinking water is scarce, canned tomatoes are used largely because of t h e water a n d vegetable acid t h e y contain. Considering t h e exchange in soil elements, there seems t o be a general agreement t h a t t h e t o m a t o plant uses relatively little phosphoric acid, b u t more potash a n d nitrogen. M u c h of t h e potash remains i n t h e vines a n d roots. In comparison with t h e a m o u n t of crop produced, t h e t o m a t o does not remove much plant food from t h e soil. T h e acidity of t h e t o m a t o is supposed t o be due t o citric acid. A small a m o u n t of a n alkaloid is also supposed t o be present in t h e juice a n d t h i s decreases a s t h e fruit ripens. D:ring ripening there is a progressive increase in t h e organic acids, sugars, starch a n d nonq.
