I N D U S T R I A L A N D ENGINEERING CHEiVIXTRY
February, 1925
values given. The corresponding ether extracts constitute 50.7 and 61.0 per cent of the same values. These relationships show that ether extracts from these materials do not constitute all of the fatty or fatlike matter contained in them. The close agreements in lipoid content of composite substances (finished noodle products), as determined directly and as
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computed from that contained in their component materials, indicate that the ammoniacal alcohol method makes complete extraction of all fatlike substances in cereal products. Results of this method may be applied in calculating the formulas used in the manufacture of composite products whose component substances contain known amounts of lipoids.
Estimation of Lipoid Phosphorus in Cereal Products’ By Olaf S. Rask2 and Isaac K. Phelps3 FOOD CONTROL LABORATORY. BUREAU OF CHEMISTRY, WASHINGTON, D. C.
OKSIDERABLE significance is attached to the phospholipin content of food products on account of the important role that phospholipins play in nutrition and in many other vital phenomena. The lipoid phosphate content of many food and medicinal products has an additional significance, because it is regarded by food and drug officials as an index to the egg or lecithin content of such products. This is particularly true of egg noodles, in which case the lipoid phosphate is arbitrarily designated as lecithin-phosphoric acid. The large amount of investigational work on phospholipins has resulted in the development of a number of methods for their extraction, isolation, and estimation. A review of these methods shows that most of them are applications of the principle first observed by Beyer, that phospholipins require alcohol as well as the common fat solvents for their extraction. Almost all of these methods are too long and complicated to be applicable to routine work. The only excevtion is Juckenack’s methodI5which was developed primarily for determining the lecithin-phosphoric acid content of egg noodles, to which its use appears to have been confined. A recent study of this method by the Food Control Laboratory shows that it fails to make a complete extraction of the lecithin-phosphoric acid in egg noodles. Therefore, for the want of a rapid and otherwise satisfactory method for the determination of lipoid phosphate, the development of such a method was undertaken. I n this work the substances semolina, whole egg or egg yolk, and noodles, used in the authors’ study of lipoids,6were employed.
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showed that this method fails to make a complete extraction of phospholipins in cereal products. If the ammoniacal alcohol method, described in the authors’ study of lipoids in cereal productsI6makes a complete extraction of all lipoids, in general, then all phospholipins of a substance will be contained in the lipoids extracted from it by this method and may be found by determining total phosphates in the total lipoids thus obtained. This postulate accords with the general principle of Beyer on which most methods for the determination of phospholipins are based. Total phosphorus, calculated as P z O ~was , therefore determined in the lipoids extracted from the substances listed in Table I and the amounts thus obtained were computed to percentages of the original substance. The results of this procedure and the percentages which the Juckenack values constitute of the authors’ values are given in the last two columns of Table I. The Juckenack determinations were made in an extractor designed especially for lecithin-P205 determinations in egg noodles (Figure 1). Resul ,s obtained by its use averaged 21.4 yer cent higher than those obtainec by the use of the Soxhlet in a seris :s of lecithin-P205 determinations on egg noodles.
The results of the first three columns of Table I confirm those of the earlier study of the Juckenack method, which
Note -Although this extractor failed to solve t h e problem of determining lipoid PzOs, i . seems probable that it will have corresp mding advantages over the Soxhlet extract >r in other extraction procedures. These r dvantages may be attributed to the high ar d uniform temperature a t which the extract on is made. The vapors of the solvent ar they ascend to the condenser completely envelop the siphon tube which contains t i e material t o be extracted. As a result, :he extraction is made a t the boiling point o ‘ t h e solvent, which insures a high and constai t temperature. I n most extractions a high temperature is desirable. Where temper%tureenters as a factor, constant temperature is also important, because i t insures uniform conditions without which uniforri and comparable results are impossibl 1.
1 Presented under the title, “Estimation of Phospholipins in Cereal Products” before the Division of Biological Chemistry a t the 61st Meeting April 25 t o 29, 1921 of the American Chemical Society, Rochester, N. Y., Originally received March 27, 1922, revised manuscript returned by authors November 11, 1924. 3 Johns Hopkins University, Baltimore, Md. 8 Wamesit Chemical Co., Lowell, Mass. 4 Landw. Vers. Sta., 14, 161 (1871). 6 2. Nahr. Genussm., 3, 1 (1900); Juckenack and Pasternack, I b i d . , 8 , 94 (1904). 0 See page 187 of this issue.
It is reasonable to assume, therefore, ;hat the lecithin-Pz05 content of the 3e materials by the Juckenack F i g u r e 1-Extractor method would have been somewhat Lecithin-PZOb D e t e r mfor ilower than those by this method n a t i o n s had the Soxhlet extractor been used. Table I1 gives a comparison of the lecithin-P,Oj content of the finished noodles, as computed from the total PZOScontained in the lipoids of their component materials, and the
Values on the M o i s t u r e - F r e e Basis (b) (a) Computed Determined from amounts directly in components (Juckenack’s (Juckenack’s (c) method) method) Percentage From lipoids Percentage SUBSTANCE Per cent Per cent ( a ) is of (. 6.) Per cent (.a.) is of (c) Semolina 0.0289 0.0548 52.7 Whole egg 1.273 ... ... 1.380 92.3 ... ... 1.745 100,o Yolk 1.745 Whole egg noodle 0.0574 0.0840 68.3 0.1125 51.0 Yolk noodle 0.0684 0.1065 64.2 0.1290 53.0 T a b l e I-Lecithin-PzO6
...
...
INDUSTRIAL A N D ENGINEERING CHEMISTRY
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resdts obtained in the same manner by direct analyses. The lecithin-phosphoric acid content of the finished whole egg or yolk noodles when determined directly by Juckenack’s method constitute 50.7 and 52.4 per cent, respectively, of the values in the second column of Table 11. Table 11-Lecithin-PnOs ((1)
Computed from amounts in SUBSTANCE comDonents Whole egg noodle O:ll25 Yolk noodle 0.1290
from LiDoids
(a)
Determined directly 0.1132 0.1308
Percentage
(a) is of ( b )
99.4 98.6
Summary and Conclusions
1-The Juckenack method for the determination of lecithin-
P,05 in egg noodles gives results which constitute about 65
Vol. 17, No. 2
per cent of the lecithin content of noodles as computed from the lecithin-PsOs content of their component materials, also determined by the Juckenack method. 2-The check results between the PZOS content of the lipoids of composite materials, extracted directly by the ammoniacal alcohol method and their PZO6 content as computed from the P~06contained in the lipoids, similarly extracted from their component substances, indicate that the total phospholipin content of cereal products may be estimated by determining the total P206of their lipoids, extracted by the ammoniacal alcohol method. 3-Lecithin-PpO6 values by the Juckenack method constitute about 50 per cent of the P205 of the lipoids extracted by the ammoniacal alcohol method.
The Agricultural Value of Some of the Newer Nitrogenous Fertilizers’,’ By J. G. Lipman and H. C. McLean N E W JERSEY AGRICULTURAL
EXPSRIMEXT STATIOX.
NEW
BRL‘NSWICK, N.J.
ECENT progress in These examples will suffice Among the newer synthetic nitrogen fertilizers amthe art of nitrogen to indicate that problems monium phosphate, ammonium chloride, and urea give incidental to the use of these fixation is of interest promise of great usefulness. They will be employed to materials must be taken to farmers, as well as to best advantage when due consideration is given to factors under consideration. c h e m i c a l engineers and of soil, crop, and climate. The crop value of any economists. New p r o d The method of application and distribution should be n i t r o g e n o u s fertilizer is ucts, as they appear on the such as to avoid interference with germination and injury. directly affected by what market, are taken under to the young plants. may be termed “internal” careful scrutiny by our exIn the preparation of fertilizer mixtures incompatible a n d “ e x t e r n a l ” factors. periment stations and their materials should not be employed. The former have to do with crop value is determined by High nitrogen content, slight hygroscopicity, nontoxicthe nitrogen content of the comparison with such standity, and suitability for mixing with a wide range of ferproduct, the readiness with ard nitrogen fertilizers as tilizer materials make pure urea peculiarly desirable which it will undergo physnitrate of soda and sulfate among the synthetic nitrogen products. ical and chemical change in of ammonia. Comparative the soil, its physiological revalues are ultimateiy established by means of pot and field experiments made under condi- action, and the presence init of substances toxic to planis. The tions varying as to crop, soil, season, and climate. The way is latter concern the conditions of soil, crop, season, and climate thus cleared for the commercializationof any material that has under which any given nitrogenous material is to be utilized. intrinsic merit and is economically within the farmer’s reach. Internal Factors Even a cursory study of the market will show that a fairly substantial number of synthetic nitrogen products are now In gaging the significance of any of these factors one must being offered for agricultural uses. For instance, the mate- consider certain fundamental relations. Everything being rials made in commercial quantities by the Badische Anilin equal, a material containing, for example, 10 per cent of und Soda Fabrik include ammonium sulfate-nitrate, potas- nitrogen is relatively less valuable than one containing 20 sium-ammonium nitrate, ammonium sulfate, ammonium per cent of nitrogen, even though this constituent in the two chloride, sodium nitrate, and urea. The first two are mixtures products is sold a t the same price per unit. The difference of ammonium sulfate and ammonium nitrate, and of potas- in favor of the more concentrated product is accounted for by sium nitrate and ammonium chloride, respectively; the others the greater ease and economy of bagging, transporting, and are single salts; and all are of a high degree of purity. The distributing the latter. Hence, among the synthetic nitrogen manufacture in Norway of calcium nitrate, ammonium fertilizers basic calcium nitrate with about 12 per cent of nitrate, sodium nitrite, and sodium nitrate is no longer new. nitrogen would be followed, in order, by ammonium phosNeither is the production, on a commercial scale, of cyanamide phate, sodium nitrate, ammonium sulfate, ammonium chlowhich has been known to farmers for nearly two decades. ride, ammonium nitrate, and urea-the last named containing I n the United States ammonium phosphate, sodium nitrite, 46 per cent of nitrogen. hydrocyanic acid, and ammonium chloride are now being The changes that these products undergo in the soil conmade, directly or indirectly, from atmospheric nitrogen. stitute another important factor. Nitrates are readily soluble in soil water and readily taken up by plants. On the other 1 Presented by J. G. Lipman before the Division of Agricultural and Food Chemistry at the 68th Meeting of the American Chemical Society, Ithaca, hand, they are not fixed chemically and under extreme conN. Y , September 8 to 13, 1924. ditions may be partly leached out of the soil. Ammonium 2 Paper N o 223 of the Journal Series, New Jersey Agricultural Experisalts are temporarily fixed, but easily nitrified. Urea is ment Station, Department of Soil Chemistry
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