The Colloidal Swelling of Wheat Gluten. 13 
Table 8. — 0.01 N lactic acid with varying amounts of flour and 
bran extracts. 
0.01 N lactic 
Water abs. in 
0.01 N lactic 
Water abs. in 
acid cont. 
g. per g. of 
acid cont. 
g. per g. of 
extract from flour 
moist gluten 
extract from bran 
moist gluten 
No extract 
2.23 
No extract 
1.48 
0.625 g. per 100 cc. 
2.16 
0.625 g. per 100 cc. 
1.12 
1.25 g. per 100 cc. 
1.81 
1.25 g. per 100 cc. 
1.02 
2.50 g. per 100 cc. 
1.47 
1.87 g. per 100 cc. 
0.91 
5.00 g. per 100 cc. 
1.25 
2.50 g. per 100 cc. 
0.82 
4.75 g. per 100 cc. 
0.33 
Table 9. — 0.01 N lactic acid with varying amounts of cane sugar. 
Cone, of sugar 
solution 
Water abs. in g. per g. 
of moist gluten 
None 
1.75 
0.1 M 
1.41 
0.2 M 
1.54 
0.5 M 
1.42 
1.0 M 
0.71 
1.5 M 
0.28 
Table 8 shows that water extracts of flour and bran reduce 
the swelHng of gluten in acid solutions. Their effect is similar 
to, tho not as marked as, the effect of neutral salts. 
Table 9 shows that nonelectrolytes such as cane sugar are 
comparatively ineffective in reducing the swelling of gluten in 
acid solutions except in high concentrations. Fischer finds the 
same for gelatin and sugar solutions. 
DISCUSSION. 
The experiments described show that the mixture of vegetable 
proteins which comprises wheat gluten behaves in a manner 
entirely analogous to the animal proteins as studied by Fischer 
and others. Moist gluten absorbs water from acid solutions, 
and the amount of absorption varies with the kind and con- 
centration of the acid. The strong acids are most effective in 
bringing about water absorption in dilute solution. Maximum 
absorption is attained with 0.01 N (0.036 per cent) hydrochloric 
acid. As the concentration increases above this point, water 
absorption becomes less and less until at a concentration of 0.1 iV 
(0.36 per cent) no absorption takes place. The weaker acids, 
lactic and acetic, show also concentrations of optimal swelling. 
