Mar. 34, 1923 
Determination of Starch Content 
997 
Accordingly, the starch content of several linseed meals, the approxi¬ 
mate degree of purity of which had been ascertained, 7 (8) was determined 
by a method of which the following are the salient points: 
After extracting with ether, the charge was leached with 70 per cent 
alcohol 8 to remove part at least of the sugars and other interfering 
substances. To correct further for any effect that might be exerted by 
interfering substances not extracted by the 70 per cent alcohol, a control 
determination was conducted, in which the starch hydrolysis was omitted 
and in which only the effect of the soluble carbohydrates was measured. 
Hydrolysis of the starch was effected by digestion with taka-diastase, 
following the method of Davis and Daish (3). 
Mucilage and other interfering polysaccharide were coagulated by 
75 per cent alcohol and separated from the soluble starch conversion 
products, presumably maltose and dextrose, by filtration. After eliminat¬ 
ing alcohol from the filtrate by evaporating over steam, the starch con¬ 
version products were hydrolyzed by acid and the dextrose was de¬ 
termined. The results obtained were corrected by deducting first the 
dextrose in the taka-diastase blank, and, second, the dextrose represent¬ 
ing the control determination in which the starch was not hydrolyzed. 
results obtained with preliminary method 
The results obtained by this method on the linseed cakes and meals 
examined and the proximate analyses of these products are given in 
Table I. 
Table I .—Starch in linseed by-products of known composition 
i 
a 
Composition on original basis. 
Composition on moisture-free 
and ether-extract-free basis. 
Material analyzed. 
i 
1 
to 
i 
8 
| 
if 
Starch. 
1 
a 
if 
<§ 
. content 
nonflax 
ter. 
1 
1 
S 
1 
w 
Ash. 
0 
E 
0 
d> 
1 
Ash. 
|-1 
r a 
Per 
Per 
Per 
Per 
Per 
Per 
Per 
Per 
Per 
Per 
Per 
Per 
Adulterated linseed meal 
cent. 
cent. 
cent. 
cent. 
cent. 
cent . 
cent. 
cent. 
cent. 
cent. 
cent. 
cent. 
(Sample 26291). 
* 38 . 0 
10.0 
7.2 
6.8 
30.5 
xao 
5-8 
8.7 
36.6 
12.0 
7.0 
25 * 7 
Linseed cake containing 
excessive foreign matter 
(traced) (Sample 27243).. 
8.6 
9.6 
1.4 
5-9 
34-8 
8.x 
5.6 
i *7 
41.1 
9.6 
6 . 7 
x6. 2 
Linseed cake (traced) (Sam¬ 
6.8 
34.8 
8.1 
6.4 
36.8 
ple 27247). 
3.8 
ia 2 
1.4 
5*3 
i *7 
41.9 
97 
Linseed cake (traced) (Sam¬ 
6. 7 
35*8 
7.8 
6. x 
ple 27262) . 
3-3 
ias 
c 1.0 
5 * 1 
i *3 
43*2 
9.4 
e 40-9 
Adulterated linseed meal 
6.8 
(Sample 27374). 
&14.0 
9.7 
1.4 
7. 2 
33-8 
8.6 
5-6 
i *7 
4a 6 
10.4 
10.0 
Flax screenings cake (traced) 
&4 
x6.0 
18. 2 
(Sample 2727 0 .. 
89.8 
9-4 
16.3 
17.9 
8.3 
19.8 
21.8 
19*5 
10.1 
Nonflax matter from flax 
screenings (composition 
22.0 
19. X 
23.5 
94 
Linseed cake (traced) (Sam¬ 
1.8 
8. x 
6.S 
32. r 
ple 27276)... 
5.6 
10.5 
5.0 
34*9 
2. x 
41.4 
95 
7 * 7 
f These meals were prepared from traced linseed cakes. The investigator took samples from the seed 
entering the rolls, traced the seed through the crushing, cooking, and pressing, and took a representative 
section of the resulting cake. The percentage of nonflax material in the seed was ascertained without 
difficulty. As practically all of the expressed oil comes from the flaxseed and for practical puiposes con¬ 
stitutes one-third of the weight of the seed, it follows that the percentage of foreign matter m the cake or 
meal is iK times that in the seed crushed. , . , , . 
s It was subsequently shown that 35 per cent alcohol percolates through linseed meal with almost equal 
facility and is, of course, a better solvent for interfering carbohydrates (p. 998). . 
a The starch was determined by the taka-diastase method, corrected by a * control determination. 
b The content of nonflax material in this sample was calculated from data obtained through inspection 
°* c^rom subsequent work, the true starch content is believed to be 1.34 per cent (1.62 per cent on the dry, 
fat-free basis). 
