ANALYTICAL EDITION
356
OF LEVULOSE AND DEXTROSE IN TABLEIV. DETERMINATIONS RAWCANESUGARS
NO.
1 2 3 4 5
R
ORIGIN Cuba Philippines Hawaii Puerto Rico Florida Santo Domingo
DBXTROSELEYULOBE
solution or in 25.84 grams of raw sugar. The final result is therefore 0.382 per cent of levulose, 0.542 per cent of dextrose, 0.924 per cent of total reducing sugars.
TOTAL REDUCINQ SUGARS
%
%
%
0.542 0.671 0.176 0.559 0.426 0.342
0.382 0.557 0.261 0.531 0.402 0.446
0.924 1.228 0.437 1.090 0.828 0.788
The levulose equivalent of the dextrose, 140.7:12.4, is again 11.3 mg., so that the figures for levulose and dextrose, third ap roximation, are not changed further. $he ratio between levulose and dextrose is thus found t o be 98.7:140.7, or as 41:59. For this ratio Table IB gives a Lane and Eynon factor of 43.3 instead of 43.4, and the total reducing sugars are therefore not 239.4, but 238.8 mg. In this articular case a second calculation, on the basis of 238.8 mg. oPtotal reducing sugars, is hardly necessary, because the difference is within the limits of error. If it is made, the second calculation gives 98.7 mg. of levulose and 140.1 mg. of dextrose in 100 ml. of
Vol. 6 , No. 5
The results of the analyses of this and other raw sugars are compiled in Table N.
LITERATURE CITED Assoc. Official Agr. Chem., J . Assoc. Oficial Agr. Chena., 15, 53 (1932). Eynon and Lane, J . Soc. Chem. Ind., 50, 85T (1931). Jackson, J . Assoc. Oficial Agr. Chem., 9, 178 (1926); 11, 175 (1928); 12, 166 (1929). Jackson and Mathews, Ibid., 15, 198 (1932) ; Bur. Standards J.Research, 8, 403 (1932). Lane and Eynon, J. SOC.Chem. Ind., 42, 32T (1923). Nijns, Sucr. belge, 44, 210 (1924). Zerban and Sattler, IND.ENO.CHEY.,Anal. Ed., 2, 307 (1930). RECEIVED April 10, 1934. Presented before the Division of Sugar Chemistry at the 87th Meeting of the American Chemical Society, St. Petersburg, Fla., March 25 to 30, 1934.
Extraction of Gossypol from Cottonseed Meal Effect of Moisture and Repeated Extraction with Ether by Different Procedures J. 0. HALVERSON AND F. H. SMITH, Agricultural Experiment Station, Raleigh, N. C.
I
PI; A PREVIOUS paper ( 2 ) data were presented showing that moisture both in the cottonseed meal and in the ether exerted a marked influence on the amount of gossypol which could be extracted. These data suggested that there is no definite limit between the ether-soluble and bound gossypol. More data are presented here to substantiate those results and to show further what occurs when cottonseed meal is repeatedly moistened and extracted with ether, and with ether saturated with water. Initial charges of 75 grams of cottonseed meal were moistened or conditioned ( 2 ) by passing a vapor of condensing steam over thin layers of meal for 5 hours, or, more conveniently, the proper amount of water was mixed in with a mortar and pestle, The conditioned meal was extracted for 72 hours and the gossypol estimated by a recently published modified method (1).
subsequent extraction. It was therefore decided to determine how much ether-soluble gossypol could be extracted from meal 1578, which had previously shown a total (bound and ethersoluble) gossypol content of 1.102 * 0.006 per cent ( 3 ) . The repeated conditioning and extraction of the charge was continued as long as appreciable amounts of gossypol could be obtained. TABLE I. GOSSYPOL RECOVERED FROM MOISTENED COTTONSEED MEALBY SUCCESSIVE EXTRACTIONS WITH ETHER BY DIFFERENT PROCEDURES EXTRACTION
PERioDs
% 1 to 6 7to14
ETHER-SOLUBLE GOSSYPOL FROM MOISTENED COTTONSEED MEAL
Group a, determinations 1 to 3 with G ether alone Group b, determinations 4 t o 6, with B ether alone Group c, determinations 7 and 8, with B ether, 10 cc. of alcohol (95 per cent), and 5 cc. of water Group d, determinations 9 and 10, with €3 ether and 5 cc. of water Preliminary work showed that' meal conditioned by increasing its moisture content yielded more ether-soluble gossypol upon successive moistening of the charge of meal and
Mg.
70
Mo.
%
%
Mg.
Mg.
AVERAGE GOSSYPOL A N D MOISTURE PER DETERMINATION
1 5 t o 17
The U. S. P. grades of ether (not for anesthesia) obtained from the General Chemical Company and J. T. Baker Chemical Company (designated in the text as G and B ethers, respectively) have consistently yielded discordant amounts of gossypol. Consequently, experiments were undertaken to determine the quantity of gossypol which could be extracted from the same cottonseed meal by the following procedure:
(Average mg. of gossypol per 100 grams of meal) GROUPc GROUPd GROUPb GROUPa Mois- Gossy- Mois- Gossy- Mois- Gossy- Mois- Gossyture pol ture pol ture pol ture pol
20.2 16.0 24.0 7.1 26.2 1.0
19.4 25.8 24.5
24.7 5.7 2.1
19.5 27.4 24.4
38.0 3.5 1.8
20.3 30.1 24.6
37.7 4.8 0.9
AVERAGE TOTAL GOSSYPOL PER DETERMINATION
1 to 6 7 to 14 15 to 17
96.1 56.5 3.0
148.2 45.2 6.3
228.2 28.3 5.3
Per cent
0.1556
0.1997
0.2618
226.0 38.3 2.7 0.2670
In the first six successive periods of extraction an average of 16.0 mg. of gossypol per determination was obtained by the G ether in group a, compared to 24.7 mg. by the B ether in group 6 (Figure 1 and Table I). The moisture content of the charges in these groups does not vary greatly and is adequate for the extraction. Groups r and cl yielded an average of 38.0 and 37.7 mg. of gossypol per determination, respectively, considerably more than groups a and b. This large difference is apparently due to the addition of water to the ether in the receiving flask, since the moisture content of the charges in the various groups is approximately the same. The discrepancy in the yield of gossypol for groups a and b compared
September 15,1934
'
INDUSTRIAL AND ENGINEERING CHEMISTRY
to c and d is distinctly shown by the total amount of gossypol obtained per determination during extraction periods 1 to 6 (Table I). Seither brand of ether without the addition of water or alcohol yielded as much gossypol in groups a and b in periods 1 to 6 as in groups c and d where water and alcohol were used with the solvent. Therefore, beginning with the seventh period of extraction, with groups a and b 10 cc. of alcohol (95 per cent) and 5 cc. of distilled water were added to the ether in the receiving flask of each determination. This procedure is similar to that employed from the first extraction period on in group c. The average amount of gossypol obtained in extraction periods 7 to 14 was small even with this change in procedure for groups a and b, and in comparison with periods 1 t o 6 was considerably less for all groups. The average moisture in the charge was adequate and quite uniform except in group d, where it increased, especially in extraction periods 11 t o 13, but an appreciably higher yield of gossypol did not accompany this increase in moisture. The yield of gossypol in group a with the changed procedure in extraction is FrGunE 1. somewhat increased over that of the other groups for the tenth, twelfth, and thirteenth periods, p!obably because of the smaller amount of gossypol obtained in the first six periods of extraction. The average amount of gossypol obtained per determination in extraction periods 7 to 14 for groups a to d does not vary much, but in groups a and b they are somewhat higher. The total amount of gossypol was less for groups c and d , although the moisture in the charge was somewhat higher for these groups than for groups a and h. With adequate moisture in the charge there is no correlation of yield of gossypol to moisture content.
AVERAGE GOSSYPOL YIELDED BY GROUPSa PROCEDURES OF EXTRACTION
357
TO
d
BY
FOUR
larger but probably does not fully account for the difference in the behavior of the two brands of ether. Of the total gossypol (1.102) in this meal, 24.2 per cent was gradually extracted by the ether in group d where water was always in contact with the solvent in the receiving flask. SUMMARY
Experiments show that by repeatedly extracting the moistened meal or residue with wet ether, considerably more gossypol can be obtained than by extraction of the air-dry meal or by a single extraction of the moistened meal. By this procedure 24.2 per cent of the total gossypol in a sample of cottonseed meal has been gradually extracted. The amount of gossypol obtained by prolonged extraction shows that there is no definite limit between ether-soluble and bound gossypol. The gossypol formerly considered to be bound can be partially extracted as ether-soluble when there is sufficient moisture both in the meal and in the ether. The amount of gossypol that can be extracted from an air-dry cottonseed meal (as has been done FIGURE 2. AVERAGEMOISTURE IN CHARGE OF COTTONSEED MEAL in the past) varies, depending chiefly upon the EXTRACTED moisture content. Because the moisture content also changes a t times, such results give no Later, further extractions of the cottonseed meal residues indication of the definite amount of gossypol present. were made, consisting of the fifteenth to seventeenth periods, Probably the most reliable and practical indication of the with the result that for all four groups small weighable amount of ether-soluble gossypol in cottonseed meal is obamounts of gossypol were obtained. The average gossypol tained when the meal containing about 20 per cent of water obtained and the average moisture content of the charges is extracted for 7 2 hours with ether to which water has been are fairly uniform throughout for the groups (Figures 1 added in the receiving flask. However, further extraction and 2). under these conditions will probably yield more gossypol. The total gossypol recovered from the meal by the four LITERATURE CITED procedures is 0.1556, 0.1997, 0.2618, and 0.2670 per cent, respectixrely. The amounts are higher in groups (1) Halverson, J. O., and Smith, F. H., IND.ENG.CHERI.,Anal. Ed., 5, 29-33 (1933). c and d, where water was always present in the flask containing the ether. The alcohol added to the solvent in group c ( 2 ) Ibid., 5 , 320-5 (1933). ( 3 ) Smith, F. H.3 and Halverson, 1. o., Ibid.9 5 , 319 (1933). did not show any beneficial effectin the presence of moisture in the charge. The presence Of water in the receiv- RECEIVEDMay 17, 1934. Published with the approval of the director of ing flask with the solvent causes the yield of gossypol to be the North Carolina Experiment Station as Paper 80 of the Technical Series.
