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IV-Moistening t h e sample with sulfuric acid is not sufficient: enough sulfuric acid should be added to act as a n oxidizer for carbon and to convert all inorganic elements present to sulfate. V-Direct evaporation of the sample with nitric and sulfuric acids, preliminary t o burning off organic matter, has proved the best method of securing uniform results and has materially reduced volatilization losses. AGRICULTURAL EXPERIMENT STATION LEXINGTOK,KENTUCKY
SOURCES AND COMPOSITION OF SOME COMMERCIAL INVERT SUGAR SYRUPS WITH NOTES ON SORGHUM SYRUP By STROUD JORDANA N D A. I,. CHESLEY
houses. It is so blended t h a t i t rarely carries over 7 2 . 5 per cent total sugars and a varying amount of this is invert, which may be seen from t h e analyses given later. It is impossible t o determine the acid value of this material with any degree of accuracy since t h e color is too dark t o allow titration. NETHODS O F ANALYSIS
For all determinations, t h e official methods, as given in Bull. I07 (revised), U . S. Dept. of Agr., Bur. of Chem., have been used. These methods have been replaced by later modifications appearing in t h e Journal of Association of Oficial Agricultural Chemists, where they may be found. I n this connection it is well to point out t h e fact t h a t sucrose cannot be estimated in these solutions by t h e Clerget method,’ and t h a t copper reduction methods have always been employed.
Received February 8. 1917
At t h e present time numerous samples of commercial invert sugar syrups may be bought on t h e market under different trade names, and during t h e past year it has been estimated t h a t more t h a n z,ooo,ooo gallons of this material were used in t h e several industries which represented an expenditure in excess of $I,OOO,OOO. The use of this material is on t h e increase a n d there is no limit t o its application, for the great value of such a solution is t h a t t h e sugars will not harden, as will sucrose, and t h a t it will retain approximately 14 per cent moisture under most conditions. This fact has been utilized t o prevent hardening of materials by substituting all or a portion of the sucrose used with invert syrup. A wide variation in these syrups will be found, going from inverted cane sugar syrups through inverted raw cane sugar syrups into the more or less complex molasses and invert sugar mixtures, which sometimes contain materials other t h a n sucrose and invert sugar. It is unnecessary t o go into detail as t o history, character and properties of invert sugar, for this is thoroughly covered in t h e literature,’ b u t in general two grades may be bought on t h e market: these are known as “light” and “dark” or by some special brand. T H E LIGHT SYRUP is generally composed of a large amount of invert sugar and a small amount of unchanged sucrose, along with a trace of ash and from 0.05 t o 0.2 per cent acidity, when calculated as tartaric. Organic acids are generally used in t h e preparation such as citric, tartaric, formic, and acid salts, as cream of tartar, but in some instances hydrochloric acid has been detected up t o 0.15 per cent, partly combined and partly free. T H E D A R K SYRUP is a complex mixture, being composed of invert raw sugar syrup, a mixture of invert raw sugar syrup and molasses, light invert sugar syrup and molasses, or invert sugar syrup and soured honeys along with wastes occurring around sugar 1 Allen’s “Commercial Organic Analysis,” 4th Ed., pp. 375-6; British Patent, 16,540, 1889, Alfred Wohl; Browne’s “Handbook of Sugar Analysis,” p. 659; Ibid., p. 273; Chemical Abstracts, 1 (1907). 645; Deul. Zuckwind, 31, 1988; U. S. Dept. Agr., Bur. of Chem., Bull. I S , 75-6; Ibid., 110, 63-4; U. S. Dept. Agr.. Farmers’ Bull. 477, 30; U. S. Patent, 1,181,086, 1916, N. W. Taussig.
Vol. 9, No. 8
RESULTS
Analyses of products gathered from various sources during t h e past four years are given below in percentages and under each grouping will be found samples of similar origin. No.
A
. B
C
1 2 3 4 5 1 2 3 4 5 1 2 3 4 5
M
6 7 8 9 10 1 2 3 4 5 6 7 8 9 10
LIGHT SYRUP Invert Sucrose Ash 77.80 3 . 3 3 0.02 78.60 2.87 0.12 76.73 0.98 0.06 76.70 2.19 0 . 0 5 77.55 2.26 0.01 69.20 11.88 Traces 73.90 8.61 Traces 72.62 6.37 Traces 68.08 10.90 0.11 76.80 2.56 0.11 74,72 2.27 74.96 2.58 75.82 2.11 75.76 2.30 Traces 73.69 3.14 Traces 75.29 0.49 Traces 74.46 3.47 Traces 2.49 Traces 74.96 74.33 2.73 Traces 74.96 1.94 Traces 44.05 33.57 Traces 5 . 4 2 Traces 72.37 65.92 14.29 Traces 69.20 11.88 Traces 2.44 0.06 75.85 8.27 0.40 71.40 47.96 30.58 Traces 66.00 11.50 Traces 9 67.88 ~. 47 _ . Traces 6 . 5 1 Traces 71.42
DARK SYRUP No. ’ Invert Sucrose A’ 1 36.92 35.09 2 48.52 22.62 3 47.62 15.49 4 47.04 22.80 5 51.32 20.35 B‘ 1 29.23 46.63 2 36.58 3 6 . 9 4 3 31.57 43.46 4 37.62 30.60 5 53.28 23.77 73.65 5.30 C’ 67.77 8.44 71.04 4.28 71.82 4.01 69.42 7.32 46.88 22.30 51.58 22.29 48.85 22.26 47.32 21.86 10 35.19 35.84 7.40 M’ 1 68.67 6.35 2 64.28 3 55.62 21.13 18.00 52.51 47.12 26.60 54.46 23.24 54.08 22.71 60.38 14.95 61.42 13.82 10 43.54 28.79
Ash 0.39 1.47 2.44 1.98 1.84 0.22 0.96 1.03 0.87 0.41 0.16 0.06 0.05 0.07 0.12 3.07 2.32 3.51 2.51 2.98 0.98 0.43 0.24 0.99 1.08 0.23 0.04 0.05 0.06 2.41
. Samples marked “ A ” show a very good inversion. The ash value of these samples would indicate t h a t mineral matter of some nature had been introduced either t o neutralize acidity or for some special purpose. Samples marked “B” do not show a good inversion. The first three show t h a t no mineral matter or foreign material is present because only traces of ash were found, but t h e last two evidently have material other t h a n sucrose added. These inversions are not as nearly complete as t h e foregoing samples, b u t they were probably stopped at this point in order t h a t there would be less tendency for dextrose a n d levulose t o separate. Samples marked “C” show very good inversion and correspond favorably with samples listed under “ A :” however, t h e amount of total sugar is not as great, 1 Jour. A . 0. A. C . , 11, 3 (1916), 138.; Allen’s “Commercial Organic Analysis,” 1, 375.
Aug., 1917
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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 E N G I N E E R I N G C H E M I S T R Y
which is accounted for by t h e fact t h a t 7 5 per cent sucrose solutions were inverted. Samples marked “M” are of miscellaneous origin. Nos. I a n d 7 represent a syrup which will not crystallize under most conditions; however, its value is not as great as i t would be h a d t h e syrup been properly inverted. No. 6 was inverted b y t h e action of hydrochloric acid and a portion of t h e acid neutralized, which accounts for t h e high ash value: this sample was very unsatisfactory because i t carried a burned taste, was dark in color a n d showed t h e presence of free hydrochloric acid. T h e other samples under this heading did not show enough difference t o warrant special remarks. Samples marked “ A ” ’ represent a dark syrup which has evidently been made from molasses and light syrup, except for No. I which was probably made from raw sugar. This is accounted for by t h e odor, taste a n d high ash values. Samples marked “B’” are very similar t o “A’.” Nos. 2, 3 and 4 were probably made from a low-grade sugar showing less t h a n 90 per cent sucrose or from light syrup a n d molasses just as in “A‘.” Samples I and 5 were probably made from raw sugars. Samples marked “C’,” Nos. I t o 5 , inclusive, represent a dark syrup made from raw sugar showing a t least 98 per cent sucrose. Nos. 6 t o I O , inclusive, were made from 50 per cent syrup, and 50 per cent bright molasses, which showed a n average ash of 5 . 5 t o 7 per cent. These last five samples show t h a t t h e ash value is a very good criterion for judging this material. Samples marked “M’” represent miscellaneous samples. Nos. I , 2 , 3, 6, 7, 8 a n d 9 were probably made from raw sugar. No. 4 was made from a lowgrade raw sugar showing less t h a n 90 per cent sucrose. No. 5 was made from 2 j per cent of No. 4 , 2 5 per cent refiner’s syrup a n d 50 per cent light syrup. No. I O was made from 50 per cent light syrup, z j per cent New Orleans molasses, a n d 2 5 per cent Porto Rican molasses. MOISTURE-HOLDING P R O P E R T I E S
F r o m practical experiments i t has been determined t h a t glycerine (95 per cent) will t a k e u p as much as 1 5 per cent of moisture, while t h e light invert .sugar syrups will retain about 1 4 per cent, b u t one must not assume t h a t these syrups will replace glycerine because of this fact. This becomes evident when glycerine a n d invert syrups are compared, for glycerine has a lubricating a n d softening effect a n d will “strike in” almost a n y porous surface a t ordinary temperature. Invert syrups are sticky, adhere t o t h e surface a n d require high temperatures or t o be used as very dilute solutions before they will “strike in.” These syrups may be used t o replace glycerine where t h a t material has been employed t o offset conditions arising from t h e use of crystallizable sugar, for this hardening is d u e t o crystallization more t h a n t o lack of moisture. SPECIFICATIONS
While i t is realized t h a t t h e requirements of t h e various industries in which these syrups are used admit
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of wide variations in composition, nevertheless i t is felt t h a t uniform classifications based upon specifications would be of value in contracting for such material. The following is therefore suggested after analysis of 150 samples, collected over a period of 5 years from more t h a n z,ooo,ooo pounds of invert syrup, which has been furnished from 13 different sources. More t h a n 500,ooo pounds of this material have been made under t h e direct supervision of one of t h e authors, and in no cases have t h e following specifications been found high or impractical. An objection might be raised over t h e percentage of total sugars required, b u t t h e limits set have not been found high. There should be no complaint about t h e sucrose invert-sugar ratio, since t h e value is directly affected by this constant. If a higher sucrose content is desired i t is a n easy operation t o a d d a sucrose solution and if invert syrups are t o be bought we recommend t h a t they should meet one of t h e following requirements : I-Light syrup special shall consist of a t least 7 5 per cent total sugars, due t o invert sugar a n d sucrose alone. The sucrose in such a syrup cannot well exceed 2.5 per cent, and t h e ash value should never exceed 0 . 0 2 per cent. Only organic acids should be used, which must never exceed 0.1 per cent, when calculated as tartaric. 2-Light syrup: similar t o ( I ) except t h e sucrose should not exceed 20.00 per cent a n d t h e syrup should be bought on its total sugar units. 3-Dark syrup special shall be made from raw sugar, water and a suitable organic acid, which shall not exceed 0 . 3 per cent b y weight of t h e syrup. At least 7 5 per cent of total sugars, due t o sucrose and invert sugar alone, shall be present a n d t h e sucrose should not exceed 5 per cent. T h e ash value of this material cannot well exceed 0.5 per cent. 4-Dark syrup shall be made from a n y suitable blend of invert syrups a n d molasses. T h e total sugars should never fall below 7 2 . 5 per cent, of which a t least shall be due t o invert sugar a n d not more t h a n l/s shall be due t o sucrose. T h e ash value of this material cannot well exceed 2 . 5 per cent. No acid value may be set, b u t in general i t will conform t o requirements under “ 3 ” above. SORGHUM S Y R U P
I n every case where invert syrups are manufactured a certain amount of raw or granulated sugar is required which means t h a t this much sugar is imported into t h e United States, only t o be used again in t h e production of invert syrups. Therefore, i t is desirable t o look for natural economical sources which will furnish t h e amount necessary, a n d incidentally build u p t h e sugar industry in t h e United States. After reviewing t h e literature on sorghum’ one’s attention is necessarily called t o t h e fact t h a t i t had t o be given u p as a source for t h e production of cane sugar because of t h e presence of invert sugar, starch, dextrin a n d 1 U. S. Dept. Agr., Bull. 20, 1888; I b i d . , 26, 1889; I S , 1890; 84, 1891; U. S. Dept. Agr.. Farmers’ Bull. 477, 1913.
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gums which prevented crystallization. Now i t has been estimated t h a t approximately I 7,000,000 gallons of sorghum syrup were produced in t h e u’. S. during t h e year 1900, and since t h a t time the industry has grown larger in certain localities. I t has also been estimated b y one farmer who has grown sorghum for jo years, t h a t t h e average cost of production of I j , O O o gallons of syrup yearly is about 19 cents per gallon. Of course there are by-products in this manufacture which may be utilized, such as seed from t h e sorghum cane for t h e production of alcohol a n d some planters claim t h a t sorghum seeds are worth as much for feeding purposes as a n equivalent amount of Indian corn. T h e fodder or roughage may also be saved and used as a food for cattle; however, very little success has been obtained by feeding this t o horses and mules on account of t h e exceedingly rough nature of t h e blades, which causes sore mouth. T h e value of t h e seeds is due t o t h e high percentage of starch which gives t h e m high food value. There is a custom in certain sections of North Carolina of feeding these cane seed-heads t o hogs and i t is claimed t h a t a row of cane will furnish as much food from t h e seeds as a row of corn t h e same length. I t will be seen, therefore, t h a t sorghum is not only a source of syrup b u t also a source of cattle and hog food which makes i t equivalent t o corn, a fact which should not be overlooked, especially at this time when food a n d food products are so scarce. T h e advantage of cane over a n equivalent amount of corn may be seen t o be t h e amount of syrup obtained from t h e stalk since corn stalks are not utilized and when this fact is taken into consideration along with t h e fact t h a t cane may be planted closer together it will be seen t h a t cane is worth approximately twice as much as corn. T h e syrup produced will furnish a source of all t h e so-called dark invert syrups a n d i t is also possible t o produce t h e light syrup b y passing t h e dark through a “Char” filter. The use of this material will make i t possible t o obtain equivalent sugar units a t approximately 7 5 per cent of t h e cost when compared with invert syrups made from cane sugar. T h e only drawback t o this source is t h a t t h e syrup is generally used u p locally a n d no centralized market exists for its purchase; however, t h e demand for this material should warrant t h e establishment of such a market. To test out sorghum along with other commercial invert syrups a representative Io-gallon sample was t a k e n at random from 1 2 0 0 gallons made a t Barnesville, Georgia, during October, 1916,and a n average analysis on this material is given herewith: AXALYSISOF
Percentages.,
..
S O R G H U X SYRUP
Solids _.-
Ash
Sucrose
Reducing Sunars
i4.63
2.82
40.00
28.42
Acidity Gums and as Extractive Tartaric 4.03
0.79
This sample was made from a variety known as Texas ribbon cane by grinding in a three-roller mill, straining t h e juice through a piece of burlap a n d allowing this t o run immediately onto a n evaporator heated by a
Vol. 9 , No. 8
wood fire. X o control was attempted; as far as could be seen, t h e only means of determining t h e finishing point was b y t h e break in t h e bubbles formed in t h e boiling syrup. This point, along with t h e heat of t h e fire, was controlled at will b y a so-called syrup maker who had been making syrup for t h e past t h i r t y years. The amounts of reducing sugars and sucrose may b e varied b y following out suggestions given b y A. Hugh Bryan in t h e Bulletin’ just referred t o ; however, for general information i t might be well t o s t a t e t h a t these methods depend on t h e fact t h a t sucrose is inverted in t h e presence of certain acids a n d enzymes. T h e general procedure is t o add very little lime, or none a t all, in defecating t h e syrup b u t t o allow t h e natural acidity t o cause further inversion in t h e sucrose cont e n t when t h e syrup is cooked. This process may be augmented by warming up t h e juice in a n auxiliary t a n k before evaporation, in which case inversion is increased. Some makers allow t h e cane t o remain in t h e field for twenty-four hours or more after cutting, which procedure may be taken for its worth. T h e fact remains t h a t t h e high ash value of finished sorghum syrup will not allow of inversion so t h a t this process must be attended t o a t t h e source a n d it is felt t h a t b y proper selection of t h e variety planted along with suitable control of t h e juice before evaporation a product may be made which will be a satisfactory substitute for t h e invert sugars of commerce. This last statement is borne out b y t h e fact t h a t sorghum h a d t o be given up as a source of cane sugar because it was possible t o obtain b u t little crystallization when t h e syrup was allowed t o stand. I t is interesting t o note t h a t t h e gums in sorghum syrup were composed largely of starch and dextrin which will prevent crystallization when taken with t h e percentage of reducing sugars present. A sample was exposed for six weeks without crystallization a n d a t t h e end of t h a t time i t showed approximately 15 per cent of water. Of course some of this was held mechanically b y t h e skin which formed on the surface and which was broken from time t o time b u t t h e moisture content will always compare favorably with light syrups. This same sample was still soft and pliable without showing signs of crystallization a t t h e end of four months. The best grade of sorghum syrup should be made from t h e natural juice of t h e several varieties of sorghum cane, b y extraction or expression and subsequent evaporation. N o alkali nor alkaline salts should be used t o defecate t h e juice. T h e finished syrup should contain a t least 70.00 per cent of total sugars, not more t h a n j.00 per cent starch a n d gummy matters and not more t h a n 3.00 per cent of ash (mineral matter). The acidity of such material cannot well exceed 0.8 per cent, due t o acids naturally present in t h e cane juice and calculated as tartaric. T h e color and taste should be large factors in judging this material. 544 PARKAVENUE BROOKLYN, NEW Y O R K 1
U. S. Dept. Agr., Farmers’ Bull. 477, 30.
