Nov., 1914
T H E JOL'RNAL OF J N D r S T R I A L A N D ENGINEERING C H E M I S T R Y
t h e gluten of t h e chlorine-treated flour is somewhat softer i n some cases, showing t h a t t h e chlorine m a y have affected t h e gluten t o some extent. Several samples of unbleached flour gave t h e following a m o u n t s of chlorine, expressed in p a r t s per million: (1) 445; ( 2 ) 503.8;(3)492; (4) 448; (5) 348; (6)3 7 3 ; ( 7 ) 4 5 2 ; (8) 484; (9) 496; ( I O ) j44. A number of samples of chlorine-treated flour on t h e Kansas market yielded t h e following amounts of chlorine expressed in parts per million: ( I ) 7 4 2 ; (2) 260; (3) j91;(4) 608; (5) 7 3 2 ; (6) 7 1 2 ; ( 7 ) 1056; (9)904. All of these gave a positive test with t h e copper wire reaction. A number of samples of bleached a n d unbleached flour were shipped t o t h e laboratory in cloth sacks, packed together. T h e unbleached flour yielded t h e following amounts of chlorine, p a r t s per million: ( 1 ) 5 2 8 ; ( 2 ) 5 5 2 ; (3) 612, ( 4 ) 598; ( 5 ) 592. I n each case a slight color developed i n t h e copper wire reaction, showing t h a t some chlorine was probably t a k e n u p by t h e unbleached flour. A sample of soft wheat gave 4 5 2 p a r t s chlorine per million; a sample of hard wheat gave 496 parts, a n d t w o samples of bran gave 464 a n d 431 p a r t s chlorine per million. S U M MA R Y
T h e chlorine content of untreated flour m a y r u n as high as j76 parts per million. Chlorine-treated flour will contain over 600 p a r t s per million of chlorine. T h e chlorine can be detected with certainty b y means of t h e copper wire reaction. Samples of u n bleached flour in contact with chlorine-treated flour m a y give t h e reaction. Chlorine-treatment increases t h e acidity of t h e flour a n d does not improve its breadmaking qualities. I n conclusion credit should be given t o hIiss Leila D u n t o n of t h e Department of Milling I n d u s t r y of t h e Kansas S t a t e Agricultural College for making t h e baking a n d gluten tests, a n d t o D r . J . T. Willard, of t h e Department of Chemistry, for suggestions in carrying o u t t h e work. KANSASSTATEAGRICULTURAL COLLEGE MANHATTAN
DETERMINATION O F PRUSSIAN BLUE I N TEA' B y G W. KXIGHT Received August 31, 1914
This method of determining t h e artificial coloring m a t t e r , Prussian blue, on t e a is t h e conclusion of a series of experiments t o ascertain a n analytical method t h a t would be rapid, accurate a n d quantitative. By means of i t , I p a r t in zoo,ooo, a n d sometimes even I p a r t in 300,000, can be detected. A m a n inexperienced in t h e manipulation can r u n four determinations in a d a y easily, a n d doubtless with experience could r u n m a n y more. T w o operators viorking independently on t h e same sample obtained 0.0019 a n d 0.0016per cent of Prussian blue. METHOD--100g. of t e a are ground t o a fine flowder in a coffee grinder, placed i n a round-bottomed distilling flask of sufficient capacity a n d moistened with enough 8 5 per cent phosphoric acid t o thoroughly 1 Contributed with the permiqsion of t h e Secretary of the Treasury . a n d the U. S. Appraiser, Port of h-ew York.
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moisten all of t h e tea. (Usually from 30 cc. t o 60 cc. are sufficient.) T h e flask is t h e n fitted with a delivery t u b e , which passes through a two-hole stopper into a mixture of 4 cc. of I O per cent K a O H solution a n d 30 t o 4 0 cc. of water contained in a I O O cc. Erlenmeyer flask. T h e Erlenmeyer flask is supported in a beaker of cold water. An outlet t u b e bent a t right angles passes through t h e other hole of t h e two-hole stopper for t h e escape of unabsorbed gases. T h e a p p a r a t u s is placed in a well ventilated hood a n d a Bunsen burner flame is placed in front of t h e outlet t u b e t o burn t h e unabsorbed gases. T h e flask is t h e n heated, slowly a t first, with a small flame a n d finally more strongly until t h e phosphoric acid begins t o distil over. Usually I O or I j minutes are sufficient for t h e distillation. After t h e distillation is completed, t h e distillate is filtered a n d t h e filtrate placed in a casserole; if acid, i t is neutralized with I O per cent N a O H solution, t h e n 3 cc. of I O per cent S a O H solution in excess are added. A crystal of FeSOl about t h e size of a pea a n d a few drops of I O per cent FeC13 solution are added a n d t h e solution boiled for I minute. HCl (sp. gr. 1.2) is t h e n added, drop by drop, t o t h e hot solution till it is distinctly acid. T h e solution is filtered a n d t h e precipitate washed with 95 per cent alcohol, until t h e washings r u n colorless. Cold I O per cent S a O H solution is dropped on t h e filter, using as little as possible b u t washing t h e whole area of t h e filter, a n d t h e n t h e filter is washed with as small a n amount of water as possible. I t is best t o drop t h e wash water, drop b y drop, from a pipette. About 4 cc. of N a O H a n d 8 cc. of water are sufficient for this operation. T h e filtrate is acidified with acetic acid a n d a few drops of HC1 (sp. gr. I.z), a few drops of I O per cent FeC13 solution are added a n d t h e n HC1 (sp. gr. 1 . 2 ) is added until a n y brown color t h a t m a y have developed has disappeared. T h e solution is t h e n placed in a casserole a n d evaporated t o half i t s bulk on t h e water b a t h ; more water is added t o dissolve a n y salts t h a t m a y have crystallized o u t , a n d t h e Prussian blue is Altered on a Gooch crucible, washed with very dilute HC1, water, alcohol a n d ether, a n d dried a t I O O O C. t o constant weight. T h e weight in grams gives directly t h e per cent of Prussian blue in t h e sample. Several samples of uncolored China and Japan teas were r u n b y this method, a n d n o Prussian blue detected. T h e n varying amounts of Prussian blue, from I p a r t in j j , o o o t o I p a r t in ~ O O , O O O , were mixed with these uncolored teas. Prussian blue was obtained in all cases up t o I p a r t in 200,ooo a n d in some cases u p t o I p a r t in 300.000. The amount appeared proportiona t e t o t h a t p u t in, b u t t h e a m o u n t was too small t o weigh except in t h e case of I p a r t in i j , o o o ; a n d in this case where I . j mg. was p u t in I mg. was recovered. As t h e purity of t h e Prussian blue p u t in was questionable, this mas a fairly quantitative recovery. Three samples which gave I spot, 2 spots a n d 3
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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 C H E M I S T R Y
spots, respectively, b y t h e Read test,’ gave 0.0005, 0 . 0 0 2 2 a n d 0 . 0 0 2 2 per cent, or I part in 200,000, I p a r t in 4j,ooo, a n d I p a r t in 45,000. Three other samples of colored t e a t h a t gave a n average of j o spots, 48 spots a n d 32 spots, respectively, by t h e Read test, a n d showed color distinctly in I a n d 2 a n d barely perceptibly in 3 b y a qualitative infusion method devised b y W. G. Berry (unpublished) gave 0 . 0 0 7 2 , 0.0044 a n d 0.0016 per cent, or I p a r t in 14,000, I p a r t in 23,000, a n d I part in 63,000. Sample number 3 repeated by a different operator gave 0.0019, checking fairly well with 0.0016 by t h e first operator. T h e writer contemplates making a more exhaustive s t u d y of t h e method as t o its suitability in t h e analysis of various classes of tea. U. s. CUSTOMS LABORATORY PORTOF NEWYORK
AN INVESTIGATION OF THE DIASTASE O F ALFALFA AND THE E F F E C T O F RAPID CURING U P O N THE F O O D VALUE O F ALFALFA2 By RALPRC. SHUEY Received May 22. 1914
INTRODUCTION.
I n a search for a commercial source of diastase among t h e green plants. alfalfa was found t o have a n exceptionally high diastatic content, and further work indicated a close relation between diastatic content a n d t h e proportion of water-soluble constituents of t h e dried plant. It was found possible, by careful a n d rapid curing, t o increase t h e diastatic value very materially; and this paper will deal principally with these relations a n d their possible economic importance. Before taking up t h e experimental work, however, i t might be well t o review briefly t h e occurrence of diastase, i t s role in t h e economy of t h e green plant and t h e chemical changes related thereto. Diastase, or amylase, may be defined as t h a t enzyme or organic catalyst which is elaborated b y t h e living organism for t h e purpose of assisting in or bringing about t h e conversion of starch into sugar. But little is known of t h e chemical nature of diastase. As ordinarily prepared, t h e substance contains nitrogen a n d might be classed with the proteins, b u t some work of Frankel a n d Hambourg3 a n d others indicates t h a t t h e protein may not be necessarily a n integral part of t h e substance, b u t t h a t t h e protein and diastase are almost inseparable on account of their colloidal nature a n d other physical properties. The action of diastase is easily affected by slight variations in conditions. Aside from t h e temperature a n d concentrations of hydrolyte, hydrolyst a n d hydrolytic products, t h e presence of very slight amounts of hydrogen-or hydroxyl-ions or of salts may produce very great changes in t h e activity or even completely inhibit action. I n t h e moist s t a t e or in solution, diastase is easily destroyed b y heat, continued heating a t 80’ C., 1 “Eighth International Congress of Applied Chemistry,” Vol. XVIII, p. 301. 2 This investigation was made in connection with Industrial Fellowship No. 2 . in the University of Kansas, during the years 1907-10, and has been withheld from publication in fulfilment of the conditions of the Fellowship Azreement. 8 Woch. fur Brauw, 2s (1906). 473.
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being sufficient b u t if perfectly dry a temperature of 100’ C. for a considerable time has no noticeable effect. As we are not concerned with t h e diastases of animal origin, they will not be discussed. The vegetable sources of diastase m a y be roughly divided into three groups : I-In t h e green plants diastase is present for the conversion of t h e deposited storage material, starch, into t h e soluble and transportable sugars which m a y , after transportation, be again deposited as one of t h e less soluble carbohydrates, starch or cellulose, or may be used up in t h e metabolic processes of t h e plant. T h e diastase f r o m green plants possesses t h e property of dissolving unboiled or granular starch t o a much greater degree t h a n does t h a t from t h e other two sources. 11-The germinating seeds elaborate a very active diastase for t h e purpose of making available t o the growing embryo t h e stored up material of t h e endosperm. Although this diastase attacks unboiled starch, i t does so only very slowly. Malted or sprouted grain is t h e most generally known source of diastase. Aside from its use in t h e fermentation industries as malt, t h e soluble portions, concentrated t o a syrup or powder, are used in t h e baking industry a n d in medicine. III-hn/Iany of t h e fungi a n d bacteria secrete diastese for t h e purpose of making available t h e food material of a starchy medium in which they are growing. This has found application in t h e moyashi or yeast used in making t h e Japanese alcoholic drink, s a k e , from rice. The diastatic extract from this fungus, Aspergillus o r y z a e , is used in medicine under t h e name T a k a diastase. HISTORY:
THE
PRESESCE
OF
DIASTASE
IK
GREES
PLAKTS
T h e first investigation of diastatic activity in green plants noted was t h a t of Kosmann’ in 1877. He made aqueous infusions of lichens, moss, algae a n d fungi, precipitated with alcohol, a n d obtained a substance which showed diastatic action in every case when starch paste was used as hydrolyte, a n d even in some cases when unaltered starch was used. The following year a monograph was published b y Baranetsky,2 describing similar work on t h e seeds, bulbs, stems a n d leaves of plants. His conclusions were t h a t t h e quantity of enzyme present a t a n y one time was very small, i t being elaborated as needed a n d used u p as fast as formed. J. Boehm3 agreed with t h e former investigators a n d added this piece of information, t h a t freezing and thawing t h e leaves stops t h e depletion of starch, a s does also immersion in a n atmosphere of hydrogen. None of these investigators used any antiseptic precautions a n d their tests were more qualitative t h a n quantitative. I n 1884, Brasse4 followed Kosman a n d garanetsky b u t ysed chloroform as a n antiseptic a n d measured t h e diastatic activity by means of t h e quantitative reduction of copper solutions in place of using t h e iodine 1
2
4
Bull. Soc. C h i m . , 27 (1877), 2 5 1 . “Die StBrkeumbildenden Ferrnente in den Ptlanzen,” Leipsic, 1878. Z e i t . fa7 d . g. Brauw, 6 (1883), 7 6 . Comptes Rcndus, 93 (1884). 8 7 8 .
