The Colloidal Swelling of Wheat Gluten. 
23 
water. A 0.5 per cent salt solution gives a higher result than 
either. Again, the dry gluten and protein figures are practically 
the same with all three washing agents, but are higher than for 
the corresponding factors of the other three flours. In other 
words, the seventh middlings gives results similar to those 
obtained with the low-grade flour, as shown in Table 10, whereas 
the first, third, and fifth middlings give results similar to those 
obtained with the patent flour of Table 10. In Table 14 are 
given the percentages of protein in the original flours which 
were used in this study. Reference to this table shows that the 
first middlings of the 1914 flour has practically the same protein 
content as the patent flour of the 1915 series. Comparing the 
figures as given in Tables 11 and 12 it is seen that these two 
flours which are alike in protein content give quite different 
figures for wet and dry gluten and protein when distilled water 
is the washing agent, but practically the same figures with 0.5 
per cent salt solution as the washing agent. Again, the third 
middlings and the patent flour of the 1914 series have practically 
the same nitrogen content. Reference to Tables 10 and 11 
brings out the fact that these two flours also give quite different 
results when distilled water is the washing agent but very similar 
results when 0.5 per cent salt solution or tap water is the washing 
agent. 
Finally, Table 13 shows that hydrochloric acid solutions in 
concentration of A/^/2,000 (0.0018 per cent) will not give a gluten 
ball. 
Table 12. — Mill-stream flours washed in water and 0.5 per cent 
NaCl solution. 
Flours 
Solution 
Wet gluten 
Dry gluten 
Protein 
Temp. 22.5" 
Per cent 
Per cent 
Per cent 
1st Middlings 
CO2 free water 
23.5 
7.1 
6.4 
0.5% NaCl solution. . 
32.1 
9.4 
8.4 
Tap water 
31.4 
9.7 
8.7 
3rd Middlings. . . 
CO2 free water 
27.8 
8.7 
7.8 
0.5% NaCl solution. . 
34.5 
10.3 
9.3 
Tap water 
33.7 
10.6 
9.4 
5th Middlings. . . 
CO2 free water 
33.7 
11.2 
10.0 
0.5% NaCl solution. . 
37.5 
11.2 
10.0 
Tap water 
35.7 
11.5 
10.2 
7th Middlings . . . 
CO2 free water 
36.0 
12.4 
10.7 
0.5%, NaCl solution. . 
38.6 
12.0 
10.3 
Tap water 
36.6 
12.3 
10.7 
