REES OA; OPTIC.4LLI- .-1CTIVE NON-SUGAR OF T H E SUGAR B E E T . OPTICALLY ACTIVE NON-SUGAR O F THE SUGAR BEET. B y V'
H REES
Received April 2 5 , 1910.
During the past two years considerable attention has been paid in European countries to the cause of excessive unaccountable loss of sugar in beet sugar factories. The reason of this has been attributed to climatic conditions which have developed a new substance in the beet t h a t is optically active and is either eliminated or destroyed in the processes of the factory. To the present time, however, no one has published an account of having definitely determined just how, or where, in the process, this loss occurs; o r of having obtained from the beet or factory products a dextro-rotatory substance which would be destroyed or eliminated by the factory processes. A summary by K. Andrlik, of the published articles concerning the existence of such a dextro-kotatory substance, was published in the Zeztschrijt jur Zuckerindustrie in Bohmen, August, 1909. I n the October and November numbers, 1909, Dr. 0. E. Kopecky has fully described his experiments along this line, extending over a period of eight years, and has left little room for doubt t h a t there has been present in the beets on which he worked a substance t h a t indicated a higher per cent. of sugar by the direct method of estimating sugar than by the inversion method. I n the same Journal, December, 1908, Ing. Fr. Herles describes his experiments in which he found t h a t the action of lime and heat on beet juice caused a reduction in the polarization (this report is supplemented in Andrlik's article above referred to), and while Herles has been unable t o satisfy many chemists as to the truth of his discovery, he has, in accordance with my experience, undoubtedly located the station where the greatest apparent loss of sugar occurs. As shown by irregularities in factory and laboratory work, this substance has been present in the beets of the Alameda Sugar Company, Alvarado, Cal., for the past five years, and for the past three years in disturbing influence has been very marked. I n January of 1909 the author began experiments i o search for some optically active non-sugar which would explain the results of observation made in the campaign of 1908, and was soon rewarded by obtaining from the evaporator thick juice a dextrorotatory substance which was not precipitated by basic lead acetate in water solution and gave a dextrorotation in acid, alkaline, and neutral solution. This substance was first obtained from the evaporator thick juice, later from the molasses, and afterward from the evaporator condensaYion water produced during the concentration of the osmose syrup. Throughout the inter-campaign all of the spare time was spent in extracting and experimenting with
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this substance, but a t no time did the specimen obtained appear to be pure, and in quantity enough, to attempt a n analysis t o determine the composition of the rotatory substance. Naturally, small quantities had to be worked with, and after the extraction and numerous washings necessary to free i t from the adhering substances there was very little left. A solution was obtained from one experiment which, when concentrated and then diluted t o just fill a 2 0 0 mm. tube, gave a reading of 30' to the right. It has been extracted from the molasses of 1904, 1905, 1907, and 1908, and from the beet and factory products of 1909. As obtained, the following properties have been ascribed to i t : It may be considered as a n acid, or a substance which, like sugar, can be combined with calcium or lead. The solutions which have contained i t free from bases have been faintly acid to phenolphthalein, but this acid may not be the rotatory substance. It was found to be very difficult to free the solution from acetic acid. It is, in a free condition, easily soluble in water, alcohol and acetone, but insoluble in ether. The lead compound, produced by basic lead acetate, is soluble in water and dilute alcohol and quite soluble in strong methyl alcohol, but almost insoluble in ethyl alcohol of 85 per cent. The calcium and sodium compounds are readily soluble in water, and also in dilute alcohol, but practically insoluble in absolute alcohol. Much more soluble in strong methyl alcohol than in strong ethyl alcohol. As obtained from the thick juice of 1908, and the evaporator condensation water from the osmosed syrup it is not destroyed by heating with dilute mineral acids, neither is i t destroyed by the usual inversion method of heating for five minutes a t 68' C. with concentrated hydrochloric acid, but long heating in such acid renders it inactive. Strong acetic acid destroys i t readily when heated on the water bath it 70' C. By heating on the water bath with milk of lime it loses its optical activity entirely, but if slowly evaporated in slightly alkaline solution i t does not lose this property, and when evaporated to dryness from a neutral solution i t may be heated to I I O O C. for hours without changing its rotatory power. It is not volatile but can be carried over from a dilute acid solution, by distilling with a current of steam. It does not reduce Fehling's solution and is not destroyed b y alcoholic fermentation. N o signs of crystallization have been ObFerved, and in the nearest approach to purity that i t has been obtained, i t was of a light amber color, in appearance resembling very closely light-colored gum arabic, but completely soluble in absolute alcohol.
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T H E J O U R N A L OF llI-DL’STRI.4L A-VD E S G I S E E R I S G CHE‘WISTRY.
The lead compound, after thorough w:ishing, is soluble in a n excess of lead acetate. If, however, i t is dried, it then becomes insoluble in lead acetate, but on boiling with water and decomposing with H,S a dextro-rotatory solution is obtained, which is not destroyed by heating with strong hydrochloric acid. The substance obtained directly from the beet is apparently more readily affected by acid than t h a t obtained from molasses, or from the condensed water from evaporating osmose syrup. My experience with this substance leads me t o believe t h a t either i t exists in the beet a s a comples, unstable compound, which readily breaks down into products of lower optical power and quite stable, or t h a t w e have originally two closely allied substances, one of which readily changes and loses its power to rotate light, while the other is more stable and requires vigorous treatment t o change its properties. The fact t h a t its lead compound is practically insoluble in strong alcohol affords a ready method for obtaining i t directly from the beet. -And the fact t h a t this lead compound is readily soluble in dilute alcohol accounts for the agreement of water and alcohol digestions when made by the usual methods. If finely grated beets are extracted with 90 per cent. alcohol and basic lead acetate added to the clear solution thus obtained, there will be produced a yellowish white precipitate. If this procedure is carefully carried out, i t will be found t h a t the polarization of the alcoholic solution before the addition of lead acetate will correspond very closely to the polarization of the water digest made with the requisite amount of lead acetate. It will also be found t h a t t h e polarization of the alcoholic solution after the addition of the lead acetate and the proper correction for dilution is considerably lower than t h a t of the water digest. This, so far as I am aware, has been attributed to the precipitation of sugar by the lead acetate in alcoholic solution. LA pure sugar solution, in the same strength of alcohol, will not yield a precipitate when lead acetate is added, unless a very large excess is used. I n the case of the beet juice in alcohol, i t is found t h a t if the addition of the lead acetate is cautiously made and time allowed for the separation, a point will be reached when the further addition of the reagent does not cause further precipitation. If, a t this point, the precipitate is filtered off and thoroughly washed with alcohol containing a little lead acetate and afterwards with water, then boiled with water and H2S passed in, the lead is precipitated as sulphide, and after cooling and filtering a solution is obtained which turns the ray of light to the right. By the addition of alcohol and lead acetate t o this solution, a precipitate is again formed. If this is washed with alcohol and lead acetate until a 400 mrn. tube. filled with the washings,
July, 1 9 1 0
gives a rotation so slight as t o be scarcely definable, then the residue boiled with water and decomposed with H,S, the solution obtained is dextro-rotatory and remains so after heating for five minutes with concentrated hydrochloric acid. The differences between the polarization of water digest and the alcohol digest, maintaining a n alcoholic strength of 85 per cent., have generally been greater than the differences between the direct and inversion polarizations, and in my determinations I h a r e not been able to obtain a quantitatil-e separation which would agree with the difference between the water and alcohol digest, though in one carefully carried out test, in which a n accumulation of several precipitates was used, the results were not far from the results obtained by inversion. By carefully carrying out comparative estimations of the sugar in the beets and the varous products of the factory, by the use of water solutions and alcoholic solutions of S j per cent. to 90 per cent., i t has been shown that there is a continual diminishing of t h e differences between the polarizations of the water and alcoholic solutions, from the entrance of t h e beets to the factory until the juice has passed through all of the saturation stations and t h a t afterward there is not the increase in these differences that we should has-e, as these saturation juices are concentrated to fillmass. This has been shown also by the inversion method of estimating the sugar. The results of determinations made during the last campaign show differences ranging from nothing to as much as one and’one-half per cent. in the beets and beet juices, and ax-eraging less for the diffusion juice than for the beets, while the differences in polarizations of water and alcohol solutions of the first saturation juices was seldom over two-tenths of one per cent. If after the defecation by lime there was no further loss of this dextro-rotatory substance, i t should occur (owing to the concentration) in the final molasses in quantities indicating two or three per cent. of sugar, but this has ndt been found to be the case, the a\-erage being only about six-tenths of one per cent. Xs prei-iously stated, this dextro-rotatory substance has been obtained from the e\-aporator condensation water when concentrating the osmosed syrup, and in the campaign of 1909, the vapors escaping from the first liming or defecation pan were condensed, and from these condensed vapors a dextro-rotatory substance was extracted. By greatly concentrating the condensation water from the evaporators, I was able to get i t from this also, but in very small amounts. Especially interesting in connection with the water solution obtained from the condensation of the vapors from the lime pan, n-as the fact that as it n-as concentrated, i t gradually became brown, and from a n almost colorless solution i t changed
E D S O S O S I S F L C E N C E OF X I I C R O - O R G A S I S ~ ~OIY S MAPLE S I ' R C P . t o a dark brown mass of the consistency and color of beet molasses, and decomposed as i t was concentrated on the water bath, yielding a brown POWder insoluble in water. I n this respect, i t conducted itself like the free acids obtained when extracting the first specimen of the dextro-rotatory substance from the evaporator thick juice. The presence of this dextro-rotatory substance in the vapors readily explains why me do not have the increased differences between the polarizations of water and alcoholic solutions of the thick syrup, fillmasses, and molasses, t h a t we should naturally expect to have by concentrating the thin juices. This may also explain a long-existing question, Why do we always h a r e a n apparent loss of sugar during the evaporation and pan boiling of sugar solutions? The theory first advanced by different writers on this subject, as to the cause of the presence of this particular dextro-rotatory substance in the sugar beet, :is., the weather conditions of the past few years does not appear to be well grounded. From the properties thus far obtained, and a review of the various methods proposed by different analysts in their efforts to establish a uniform and correct method for estimating the sugar in the beet, we find good evidence to indicate t h a t i t has always been a constituent, and t h a t the increased percentage in the beets of the present day is more than probable, largely the result of seed selection, although i t malbe that the quantity is altered by the weather conditions. During the campaign of 1909 it was found in beets from widely different localities, where seasonal and climatic conditions were entirely different. I t was found in beets grown a t sea-level and those grown a t sei-era1 thousand feet elevation, in beets grown without rain or irrigation and in beets grown with both rain and irrigation. It has also been found in beets that have had a second growth and ha\-e remained in the ground all winter. From all of these various conditions the differences have not i-aried materially more than from the beets taken from the same field a t the same time. It thus appears that locality and climatic conditions are not the primary cause for the presence of this dextro-rotatory substance in the beets. I n conclusion, I wish to say that my experience has fully coni-inced me t h a t the observations of Dr. Kopeck?-, and other chemists who have found differences between the polarizations by the direct and by the inversion methods, have been correct, and that the probable reason why these differences have not peen greater in many cases, and why other chemists have failed to find any such differences, has been due to the destructive action of the acetic acid liberated from the lead acetate by the hydrochloric acid, added for the inversion. Also, my work has shown that the disco\-ery of Ing. Fr. Herles that there is a
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reduction of the polarization of t h e , beet juice and diffusion juice, when they are heated with lime, and also that i t is possible to precipitate this substance by lead acetate in very strong alkaline solution, as with caustic lime and basic lead acetate in combination, is correct. It is my intention to continue the study of this substance and, if possible, to ultimately determine its composition. A L . 4 U E D 4 sUG.4R CO ALVARADO,
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c.4LIFORNIA.
THE INFLUENCE O F MICRO-ORGANISMS UPON THE QUALITY O F MAPLE SYRUP. By H. A. EDSON.
Received April 23, 1910
I n certain climates and under specific weather conditions in the spring of the year, a flow of sap occurs from fresh wounds in the twigs and trunk of certain trees of the Accr genus. By evaporation to the proper consistency of the sap of certain species, particularly the rock or sugar maple, Acer saccharum Marsh, syrup and sugar are obtained. A detailed discussion of the conditions governing sap flow is given in Bull. 103 of the Vermont Agricultural Experiment Station. It is sufficient, a t this time, to note that the sap is obtained only during the three or four weeks which immediately precede the unfolding of the leaf buds, and that the flow is intermittent, being divided into what are technically termed runs. Freezing nights, followed by a temperature somewhat above 40' F. during the day, and the absence of heavy winds and excessive sunshine, afford the best sugar weather. The sap is obtained by boring a hole I ' 2 inch in diameter and 11J2 to z inches deep in the trunk of the tree and inserting a round hollow spout, preferably of metal, upon which is hung a bucket to receive the sap as i t flows, drop by- drop, from the wound. It is gathered after each run and concentrated as rapidly as the facilities of the boiling house will permit. The appearance of the sap undergoes a marked change as the season progresses. That first obtained is clear and transparent and possesses a delicious sweet flavor, but with the advance of the season, as the days become warmer and the freezing nights less severe and less frequent, the sap often becomes cloudy and discolored and certain unpleasant flavors develop. Such sap, while usually free from acid, is popularly termed sour. Several types of this sour sap are recognized by sugar-makers. Milky sap, stringy sap, red sap, and particularly so-called green sap are among the more common kinds. Green sap is almost always observed just before the close of the season, when the leaf buds are ready to open, and i t is a matter of popular belief that the swelling of the buds is accompanied by a change in the sap within
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