INDUSTRIAL AND ENGINEERING CHEMISTRY
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DISCUSSIONOF RESULTS Figure 1 shows that an increase in the concentration of salts in the phosphate and the acetate series caused a reduction in the intensity of the blue color of the print, whereas in the sodium chloride and ammonium chloride series no apparent change occurred. It seems clear that the effect was not caused by small changes in the hydrogen-ion activity in the sensitizing solutions. I n the diammonium phosphate series, the prints showing the least color were made from solutions having practically the same hydrogen-ion activity as the untreated solutions. The sodium phosphate series shows the same reduction of color as the diammonium phosphate series up to the limit of solubility of the disodium phosphate, although the pH values of the two series are considerably different. I n the sodium acetate series a marked difference in depth of color occurs in the last two prints of the series with very little change in pH. The decrease in sensitivity
Vol. 25. No. 4
of the paper is quite definitely correlated with the increase in anion concentration in the phosphate and acetate series. Ammonium chloride and sodium chloride seem to have no appreciable effect. It may be significant that phosphate and acetate form very insoluble iron compounds. CONCLUSIOXS The effectiveness of diammonium phosphate in preventing the formation of blue color in the white portions of blue prints is due, not to changes in the hydrogen-ion activity, but to a decrease in the sensitivity of the paper caused by the presence of the negative ions. LITERBTURE CITED (1) MacInnes and Dole, J. Am. Chem. SOC., 52, 29 (2) Schneider,
(1930).
M., Z . physik. chem. Unterricht, 39,271 (1926).
RECEIVED September 19, 1932.
Sugar Beets Relation of Inorganic Constituents to Sugar Content and Purity A. R. NEES, The Great Western Sugar Company, Denver, Colo.
T
The amount and composition of the ash of sugar c o n s t a n t so that the principal H E study of the b r o a d beets bear a definite relation to their sugar condifference between l o w - p u r i t y problem of the effect of and high-purity beets lies in the agricultural p r a c t i c e s , tent and purity* Ash (percentageOn matter) ratio of soluble to insoluble nonsoil t y p e s , climatic conditions, etc., on the yield and q u a l i t y or calcium and magnesium oxides (Percentage On sugars. In considering the facash) are the components which serve as the most tors which affect the quality of of s u g a r b e e t s r e v e a l e d the reliable criteria of the quality of beets. The beets, these p o i n t s s h o u l d be fact that there exists a r a t h e r amount and composition of the ash are influenced kept in mind. definite r e l a t i o n s h i p between The principal data to be disthe quality of beets the by the soil, by seasonal variations, agricultural cussed resulted from the analysis amount and composition of the i n o r g a n i c constituents. This practices, etc- For excessive nitrates of beets obtained during the 1931 in the soil stimulate the assimilation of undesirharvest. T h e s a m p l e s were present discussion will be conable inorganic constituents such as sodium and taken from four widely separated fined chiefly to a consideration chlorine, with the result that the beets are high in factory districts and included of this r e l a t i o n s h i p with only beets from fields producing good incidental reference to the varitotal ash and low in quality. and uoor beets in each district. ous a g r i c u l t u r a l problems inIn a i d i t i o n to these, samples volved. Both sugar content and purity enter into the evaluation of were also taken from an experimental field where various types the quality of beets. It almost always follows that beets of of fertilizer treatments were being studied. District 1 is in high sugar content are high in purity. It is also true that, Wyoming and habitually produces beets of high quality; diswhile the sugar decreases with decreasing purity, the soluble trict 2 in Colorado, high-quality beets; district 3 in northern nonsugars increase a t a much more rapid rate than the sugar Colorado, beets of about average quality; and district 4 in decreases, so that even beets of low sugar content would be eastern Colorado, beets of poor quality. The data by disof relatively high purity if the soluble nonsugars remained tricts are given in Table I and will be discussed Inter. All beets constant. It is a peculiar fact that, on the average, the total were of a standard commercial variety. Table I1 gives the average composition of the ash of beets nonsugars, expressed as percentage on beets, are practically of various purities expressed as percentage on dry matter and TABLEI. AVERAQECOMPOSITION OF INORGANIC CONSTITUENTSpercentage on ash, respectively. The table is arranged from OF BEETSFROM DIFFERENT DISTRICTS left to right in the order of diminishing pulity. All samples - P E R C ~ N T A Q E ON DRYMATTER- c P E R r E N T A Q n O N ASHfalling within the purity range indicated a t the head of the District: 1 2 3 4 1 2 3 4 column are included, regardless of the district from which they Purity originated. The purity, sugar content, and average weight Su ar5 Asg of the beets, as well as a complete analysis of the ash, are Si02 R203 given. Fen03 MnO CaO MgO
KzO NarO
c1 803
Pros
NzOb Percentage on beets.
ANALYTICAL PROCEDURE Each sample consisted of a number of beets, usually ten or fifteen. They were carefully cleaned to remove all of the adhering soil particles. They were then ground in a food chopper and the
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by distillation under reduced ground m a t e r i a 1 thoroughly p r e s s u r e (about 5 inches, or mixed. Separate samples for 12.7 cm., of m e r c u r y ) i n t o the determination of ash, sugar, p u r i t y , dry matter, chlorine, s t a n d a r d s u l f u r i c acid. A blank was run at the same time. manganese, and nitrates were The nitrates were calculated as weighed immediately. Ash Nz06, percentage on dry matter was determined on 100 grams of beets by first drying and then and percentage on ash. It is obvious that the nitrates will charring at a low temperature.' appear in the ash as carbonates. The ash so obtained was used The carbonates, as Con, were for the determination of all the calculated as the difference bebases, except manganese, and tween the sum of the other ash for SO3 and P2O6. Silica was first removed in the u s u a l constituents and one hundred. manner and the solution of ash This figure represents not only constituents diluted t o 200 ml., the COZ r e s u l t i n g from the combustion of n i t r a t e s , but from which aliquot p o r t i o n s were taken for the various dealso that r e s u l t i n g from the terminations. Calcium, magcombustion of o r g a n i c acids. nesium, and phosphorus were It is always true that the total determined by a four-tenths bases present in the ash far exportion. The phosphates were ceed the total acids, including separated from calcium a n d Con. This may be due to the magnesium by precipitation formation of complex b a s i c with sodium a c e t a t e in the phosphates. This interesting presence of an excess of iron. chemical problem, however, is The phosphates were then denot related to the present distermined in the iron phosphate cussion. precipitate by precipitation as ammonium phosphomolybdate FIGURE 1. AVEXAGE COMPOSITION OF IKORGANIC CONSTITUConsider the results given and titration with 0.1 N sodium ENTS OF BEETSOF DIFFERENT PURITIES in the first part of Table 11, hydroxide. Calcium and magnesium were determined as the expressed as p e r c e n t a g e oxalate and pyrophosphate, respectively. A reprecipitation of the on dry matter. It is a t Once evident that there is a definite magnesium is necessary in order to avoid contamination by sodium beheen the percentage ash On dry matter and the acetate. Reprecipitation of the calcium was found to be unnecessary. Iron, aluminum, and SO3 were determined on the five- Purity of the beets. Beets of high Purity are low in ash, as tenths portion which was also used for the determination of alka- might be expected. This relationship is so definite that a lies. Phosphates must be separated from the iron and aluminum rough estimation of the purity may be made if the ash conbefore they are finally ignited and weighed as the oxides. Iron tent is known, ~h~ influence of the ash content on the alone was determined on a one-tenth portion by the usual colorimetric method. The regular Drocedure was follolyed for the purity is due to its effect on the ratio Of soluble to insoluhle purification and separation of t6e total alkalies. Potassium was nonsugars. determined by the perchlorate method. Manganese n-as deterThe interesting point is that all of the ash constituents do mined by the periodate method. Chlorine was determined on a not increase as the total ash increases. Practically all of the in the presence of sodium carseparate sample which was bonate. The determination was by the Volhard method, Ni- increase is due to the bases potassium and sodium, and to acids trates were determined on the original ground beets by reduction in the form of chlorides and nitrates. There is also some indiwith granulated metallic aluminum in alkaline solution, followed cation that there is a n increase in the amount of organic acids Or Of Organic compounds. of the other constitu1 bssoc. Official Agr. Chem., Methods of Analysis, 3rd ed , p 278, Sect. 8 (1930). ents, such as calcium, magnesium, iron, phosphates, etc., TABLE11. AVERAGECOMPOSITION OF INORGANC CONSTITUENTS OF BEETSOF DIFFEREXT PURITIES Purity range:
ABOVE^^
90
TO
91.9
85
TO
89.9
86
TO
87.9
84
TO
85.9
82
TO
83.9
81 9
BELOW 80
3 81.9 20.5 (582.2) 14.5 5.76 0.016 0.015 0.0054 0.0040 0.145 0.366 2.076 1.136 1.119 0.115 0.240 0.301 0. so5
4 76.5 18.0 (511.2) 11.5 7.57 0.029 0.014 0.0060 0.0045 0.159 0.430 1.548 3,264 0.761 0.116 0.146 1.164 1.572
3 81.9 14.5 5.76 0.28 0.29 0.10 0.07 2.57 6.34 36.62 19.32 17.96 4.60 2.07 5.23 13,98
4 76.5 11.5 7.57 0.43 0.17 0.08 0.06 2.14 5.95 22.00 31.90 16.10 2.48 1.70 15.31 20.76
80
T o
P E R C E X T A G E O N DRY M A T T E R
Samples in av. Av. purity Av. wt.,01. (grams) Sugar" Ash Si02
RzOa
FezOa MnO CaO MgO Kz0 NarO
c1
SOa
Pros Nitrates (NrOs) COz (calcd.)
6
92.7 2 8 . 3 (803.7) 19.2 2.24 0.028 0.013 0.0049 0.0034 0.150 0.264 0.867 0.198 0.129 0.062 0,187 0,0035 0,353
14 90.9 23.8 (675.9) 18.4 2.62 0.015 0,012 0.0041 0,004; 0.146 0.310 1.045 0.308 0.231 0.074 0,223 0.017 0.403
S 89.: 30 (871.9) 17.4 3.12 0.013 0,015 0.0045 0.0041 0.126 0.307 1.186 0.435 0.318 0.092 0,228 0.045 0 469
,
8 86.5 21.7 (616. 3) 15.0 4.00 0.020 0.018 0.0052 0.0048 0.153 0.350 1.478 0.587 0.619 0.105 0.276 0.127 0.501
8 84.8 21.4 (607.8) 15.0 4.21 0,022 0.016 0,0057 0.0037 0.149 0.362 1.370 0 ,i 7 0 0.579 0.104 0.242 0.220 0.662
4 83.2 2 8 . 4 (806.6) 14.3 4.77 0.016
8 84.8 l5,O 4.21 0.57 0.33 0.14
4 83.3 14.3 4.77 0.34 0.40 0.12 0.07 3.17 7.61 34.06 18.99 11.59 5.33 ?,53 . l l 18.58
0.019
0.0053 0.0033 0.150 0.365 1.623 0.911 0.435 0.119 0.255 0.339 0.886
I' E R C E E T I O E O S .4SH
Samples in av. Av. purity Sugara Ashb Si02 RzOa FeJOs MnO CaO
6 14 92.7 90.9 19.2 18.4 2.24 2.62 1.22 0.59 0.59 0.47 0.23 0.16 0.15 0.18 6.88 5.56 11.82 11.68 38.56 36,75 NarO 9.56 11.67 c1 5.69 8.47 P206 8.33 8.39 SO8 2.86 2.92 Nitrates (NrOs) 0.65 0.16 COz (calcd.) 15.78 15.39 a Percentage on beets. b Percentage on dry matter.
%2
8 89 2
17.4 3.12 0.43 0.42 0.15 0.13 4.09 10.02 3:. 7 5 14.10 10.12 7.33 2.97 1.44 15.04
8 86.5 15.0 4.00 0.53 0.51 0.15 0.12 3.94 8.96 36.92 14.84 15.22 7.22 2.64 3.19 12.53
0.09
3.63 8.73 34.32 18.00 13.33 5.85 2.52 5.22 15.72
,
INDUSTRIAL A N D ENGINEERIIVG CHEMISTRI-
464
TABLE111. COMPARISON OF 1930 Purity range:
ABOVE92 90 TO 9 1 . 9 1931 1931 Av. purity 92.7 90.9 Samples inonav. 6 14 18.4 beets 19.2 on dry matter 2.24 2.62 5.56 6.88 11.82 11.69 Kz0, %,on ash 38.56 36.57 11.67 Nas0, YOon ash 9.56 C1, % ' on ash 5.69 8.47 on ash 2.86 2.92 on ash 8.33 8.39 0.65 NrOa, on ash 0.16 COz, o on ash (calcd.) 15.78 15.39
%,
1
88T089.9 1930 1931 88.5 89.2 4 8 17.5 17.4 3.03 3.12 5.58 4.09 10.48 10.02 38.41 37.75 8.58 14.10 4.11 10.12 2.39 2.97 8.12 7.33 2.54 1.44 18.04 15.04
AND
1931 BEETSOF
86 TO 8 7 . 9 1930 1931 86.3 86.5 2 8 16.1 15.0 3.75 4.00 4.84 3.94 7.41 8.96 35.43 36.92 11.48 14.84 5.87 15.22 2.66 2.64 6.55 7.22 3.29 3.19 24.01 12.53
remain practically constant. These elements make up the inorganic part of the structural matter of the beet, and the fact that they are constant indicates that the structure requires a fairly constant supply of these elements, regardless of the purity and sugar content. It follows as a matter of arithmetic that, since calcium, magnesium, and certain other constituents remain constant in beets, these elements will decrease in percentage on ash as the total ash increases. This being true, the composition of the ash itself may be taken as a measure of the quality of beets. This is often advantageous when the accurate determination of ash on beets or dry matter is impractical. The second half of Table 11,where the results are calculated as percentage on ash, shows that calcium, magnesium, iron, manganese, sulfates, and phosphates decrease in a regular manner as the purity decreases. Potassium also tends to decrease, but the variation is not great except in extreme cases. There is a marked increase in sodium and in chlorides and nitrates. The results are shown graphically in Figure 1. Chlorine shows wide variations and the presence of this element, more than any other, seems to be dependent on climatic conditions, character of soil, and other factors. Calcium and magnesium, on the other hand, vary in a regular manner and are a reliable indication of the quality of beets. Beets, the ash of which contains on the average less than 3.5 per cent CaO and less than 8.5 per ceiit MgO, are of poor quality. The ratio of potassium to sodium in the ash shows some interesting characteristics. Normally this ratio is about 2 or 2.5 to 1. I n some cases, however, the ratio becomes less than 1; that is, there is more sodium than potassium, a condition common only in marine plants. Kitrates vary from indeterminable quantities in very good beets to as much as an equivalent of 20 per cent NzOs on ash in very poor beets. The presence of nitrates in excess of 5 per cent N206on ash, or 0.06 per cent nitrogen on dry matter, is a sure indication of poor quality.
EFFECT OF SEASONAL VARIATIONS
It is evident that the quality of beets is determined by those factors which influence the assimilation of inorganic constituents from the soil. Three such factors may be listed: character of the soil, climatic conditions and seasonal variations, and hereditary characteristics of the beet. These three factors are in general so interrelated that a separate evaluation of their effects cannot be made. Howeyer, certain data are available which are of interest. For example, a comparison can be made of beets grown in 1930 with those grown in 1931. It happens that the average quality of the 1931 crop was much better than that of the 1930 crop. Therefore, by comparing beets of the same purity for the two years, some idea is obtained of the difference in composition caused by seasonal variations. The data are given in Table 111. It is evident that ash, percentage on dry matter, is practically the same a t any given purity for both years. Calcium is slightly higher and magnesium is slightly lower in
CORRESPOXDINQ
84 TO 8 5 . 9 1930 1931 85.0 84.8 12 8 14.8 15.0 4.06 4.21 4.30 3.63 7.20 8.73 39.14 34.32 12.76 18.00 7.61 13.33 2.66 2.52 6.08 5,85 5.86 5.22 21.01 15.72
Vol. 25, No. 4
PURITIES
82 Po 8 3 . 9 1930 1931 83.4 83.2 4 4 14.5 14.3 4.59 4.77 3.08 3.17 6.66 7.61 34.44 34.06 12.07 18.99 8.15 11.59 2.18 2.53 6.78 5.33 8.48 7.11 25.97 18.58
80 TO 8 1 . 9 1930 1931 81.2 80.9 3 3 13.0 14.5 5.06 5.76 2.75 2.57 6.40 6.34 38.73 36.62 14.25 19.32 10.05 17.96 2.61 2.07 5.09 4.60 11.34 5.23 18.07 13.98
1930 than in 1931, but the difference is not significant. The most striking thing is that at any given purity the sodium and chlorine are much higher in 1931 than in the previous year. Since no other constituent varies greatly, and since the total ash remains constant, it follows that the difference is made up of organic acids whose presence is indicated by the amount of COz, which is decidedly higher in the 1931 beets. From these observations it may be concluded that, while the total ash content remains constant for any given purity, there is a yearto-year variation in its composition, which is due to variations in the assimilation of sodium and chlorine and the elaboration of organic acids.
EFFECT OF SOIL The influence of soil alone is much more difficult to demonstrate. However, certain districts habitually, year after year, produce better beets than other near-by districts. It seems certain that a t least a part of the difference is due to the character of the soil. I n Table I the average analysis of beets from cach of the four districts is given. The only outstanding characteristic that may be attributed to differences in soil is the high chlorine in the beets from districts 2 and 4. TABLEIV. EFFECT OF FERTILIZER TREATMENT ON CouPOSITIOS OF INORG.4NIC CONSTITUENTS OF BEETS PERCENTAQE ON DRY MATTER Plot 1 Plot 2 76.6 Purity 86.9 2 3 . 0 (653.2) Av. wt. beets, 02. (grams) 1 6 . 1 (457 10.7 15.0 Su ar Yo on beets 3.35 6.14 As% % on dry matter 0.028 0.033 sio; 0.011 0.027 RzOa 0.006 0.008 FezOa 0.004 0.006 MnO 0.133 0.176 CaO 0.479 0.408 MgO 1,951 1.162 Kz0 1.422 0.513 NalO 0.895 0.325 c1 0.127 0.111 SO8 0.224 0.261 PZOS 1.211 0.131 NZOL
PERCENTAGE O N ASH Plot 2
Plot 1
...
...
0.98 0.85 0.25 0.14 5.26 12.18 34.69 15.29 9.68 3.30 7.79 3.95
...
...
...
...
0.45 0.17 0.10 0.06 2.16 7.80 31.80 23.18 14.59 2.07 3.66 19.46
Fertilizer treatments are, of course, a part of the problem and the effect of certain of these is illustrated by the data in Table IV. These beets were taken from plots in an experimental field which received exactly the same treatment throughout the season, except for the type of fertilization. Plot 1 received 375 pounds of triple superphosphate per acre and plot 2 received 125 pounds of phosphate and 25 tons of manure per acre. The difference in the composition of the beets produced by the two plots is significant. The purity and sugar content of the beets from plot 2 were materially reduced, and the ash content correspondingly increased. The most striking difference in the composition of the inorganic constituents is in the sodium, chlorine, and nitrates, which are much higher in the beets from plot 2. The manure treatment stimulated the assimilation of these elements and a t the same time depressed the assimilation of phosphates and
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INDUSTRIAL AXD ESGINEERING CHEMISTRY
sulfates. It is common knowledge that excessive manuring results in the production of poor beets. It is also well estabblished that soils which are high in available nitrogen also produce poor beets. These and other observations lead to the conclusion that excessive soil nitrates, whether from manure or other sources, are capable of stimulating the assimilation of inorganic elements, especially sodium and chlorine, to such an extent that the purity and sugar content of the beets are adversely affected. Or in more specific terms, excessive nitrates tend to retard the elaboration of sugar and to increase the ratio of soluble to insoluble nonsugars. The hereditary characteristics of the beets also influence the amount of the various inorganic elements which will be taken from any given soil under the same growing conditions. Individual beets from a pure bred strain showing a variation of only 10 per cent in the sugar content will vary as much as 400 per cent in chlorine and 50 per cent in calcium and magnesium. The average composition of ash of different strains grown side by side shows variations of over 400 per cent in chlorine; the sugar and purity vary less than 5 per cent,
465
It is obvious, therefore, that variations in the quality of beets are the result of a combination of many complex factors, but that on the average these variations follow certain welldefined rules with respect to the relation between sugar content and purity and the amount and composition of the ash CONCLUSIONS It has been shown that the amount and composition of the inorganic constituents of sugar beets bear a definite relation to their purity and sugar content. The ash (percentage on dry matter) or the calcium and magnesium content of the ash are the components which serve as the more reliable index to the quality of beets. The presence of excessive amounts of nitrates in the soil is detrimental, since they stimulate the assimilation of certain undesirable soil elements, especially sodium and chlorine, and thereby increase the ratio of soluble to insoluble nonsugars. RECEIVEDSeptember 10, 1932 Presented before the Division of Sugar Chemistry a t the 84th Meeting of the 4meriran Chemlcal Soriety, Denver, Colo , August 22 to 26, 1932
Effect of Storage on Vitamin A in Dried Foods G. S. FRAPS AND RAYTREICHLER, Agricultural and Mechanical College of Texas, College Station, Texas
T
HE recognition of the importance of vitamin A in
human and animal nutrition has increased the commercial importance of some foods or feeds known to be good sources of vitamin A. Alfalfa meal, alfalfa leaf meal, yellow corn, and some other feeds are used by feeders and by manufacturers of commercial feeds, partly for the purpose of supplying vitamin A. Preference is given to certain human foods on account of their high content of vitamin A. The effect of storage on vitamin A thus becomes of industrial as well as of agricultural importance. Information regarding the effect of storage upon vitamin A in foods is limited and somewhat contradictory It is generally accepted (6) that cod liver oil or vitamin A concentrates, when mixed with ground foods as in a poultry mash, loses its vitamin A in a comparatively short time. The vitamin A naturally present in foods is considered to be more stable, but definite information is limited.
PREVIOUS WORK Jones, Murphy, and Moeller (3) claimed that there was no appreciable destruction of vitamin A in eggs when they are stored in the frozen condition over a period of 9 years. Tso (8)announced that Chinese preserved duck eggs are as rich in vitamin A as fresh duck eggs. Manville (4)states that eggs kept in cold storage a year lost 75 per cent of their vitamin A, and that those kept in water glass lost 50 per cent in 18 months. Morgan and Field (6) claim no decrease occurred in the vitamin A content of both sulfured and unsulfured apricots and prunes stored a t 0" C. for a period of more than a year. Rethke and Kick (1) report there was little deterioration in the vitamin A content of yellow corn stored for one year, either whole, cracked, or finely ground, and that the vitamin A content of dried alfalfa hay was not influenced materially by storing for one year, either ground or unground. Quinn et al. (7) &ate that the loss of vitamin A in dried spinach amounted to approximately 70 per cent upon storage
for a period of 12 to 15 months. Von Wendt (9) reports that the vitamin A content of food diminishes during the winter months, that the vitamin A is slowly oxidized xhen foods are stored, and that cattle fodder, such as hay and carrots, becomes markedly deficient as a source of vitamin A as the winter months progress; hence milk and other dairy products also become deficient in vitamin A.
VITAMINA TESTS The material (all finely ground except some unground samples of corn) was stored a t room temperature in maPon jars. All samples were exposed to the diffused light of the laboratory and remained tightly closed except while portions were being removed for feeding. With the unground corn, just enough was removed and ground to feed the rats from 2 to 3 weeks. Units of vitamin A were determined by the ShermanMunsell method as used in this laboratory ( 2 ) . A unit of vitamin A is taken to be the amount sufficient to produce a growth of 24 grams in 8 weeks on rats previously depleted of vitamin A. As it is difficult to secure exactly this growth, the units were in some cases estimated from different gains on the basis of experience with the test animals. The rats were continued on a ration deficient in vitamin A for 28 days; then they were weighed every other day until their weight remained constant for 6 days or until a loss in weight occurred. At this point six or more rats were fed weighed amounts of the feed to be tested for 8 weeks. Usually they were fed daily, except Sundays, but, in some cases where the feed was high in vitamin A, they were fed twice a week. Average details of the tests are given in Table I with the estimated units of vitamin A found a t the various periods, and the approximate percentages of the original vitamin A which were lost on storage. The data show clearly a loss of vitamin A during storage of alfalfa leaf meal, dried black-eyed peas, dried green sweet pepper, p,owdered whole milk, and yellow corn, either in the whole grain or in the meal.
