18 
BULLETIN 1471, U. S. DEPARTMENT OF AGRICULTURE 
Some of these seeds are easily removed by common cleaning 
deA T ices commonly employed at cleaning houses. Others, on account 
of their shape and size, can not be removed without serious loss of 
the flaxseed itself. Among these are green and yellow foxtail, wild 
buckwheat, barnyard grass, cow cockle, dock, smartweed, ragweed, 
flalse flax, and many kinds of mustard. 
Inasmuch as their presence in commercially clean flaxseed influences 
the quantity of oil in direct relation to the percentage of such foreign 
material present, a study was made of the oil content of the foreign 
material which can not be removed by the usual methods of grain 
cleaning and which is generally referred to as inseparable foreign 
material. This material was grouped into two divisions. Seeds of 
a pronounced oil-bearing nature were placed in one group and seeds 
of a small or negligible oil content were placed in a second group. 
The data from these tests are given in Table 12. The average oil 
content of the 55 samples of oil-bearing seeds was 31.18 per cent. 
The lowest quantity noted was 17.43 per cent obtained from a sample 
of mustard seed. The highest oil content noted was 46.52 per cent, 
also found in a sample of mustard seed and in a sample of charlock. 
The oil content of such oil-bearing seeds as are here analyzed will 
vary 29 per cent. This is almost three times the average variation 
found in flaxseed. 
Table 12. 
-Oil content and iodine value of foreign material {weed seeds) 
commonly present in market samples of flaxseed 
OIL-BEARING SEEDS 
Charlock 
(Brassica 
arvensis) 
Mustard 
(Brassica 
sp.) 
False 
flax 
( Camelina 
dentata) 
Winter 
rape 
(Brassica 
napus) 
Wild sun- 
flower 
(Helian- 
thus 
annuus) 
r i Average 
spJ | seeds 
7 
35.10 
46.52 
26.21 
20.31 
38 
33.73 
46.52 
17.43 
29.09 
6 
33.41 
36.16 
29.91 
6.25 
1 
44.07 
44.07 
44.07 
1 
20.53 
20.53 
20.53 
2 
19.68 
20.28 
55 
31.18 
Minimum per cent of oil 
19.09 
1.19 
IODINE VALUE 
120.7 
125.4 
116.1 
9.3 
113.9 
118.5 
99.7 
18.8 
143.8 
149.9 
137.7 
12.2 
105.0 
105.0 
105.0 
148.1 
148.1 
148.1 
NONOIL-BEARING SEEDS 
Green 
foxtail 
(Chae- 
tochloa 
viridis) 
Cockle 
( Vaccaria 
pyrami- 
data) 
Wild 
buck- 
wheat 
Lambs- 
quarters 
(Cheno- 
podium 
album) 
Pigweed 
(Amaran- 
thus 
retro- 
flexus) 
Dock 
(Rum ex 
patentia) 
Average 
all non- 
oil-bear- 
ing seeds 
10 
6.17 
6.31 
6.03 
.28 
5 
4.76 
7.41 
2.94 
4.47 
6 
3.65 
5.31 
2.27 
3.04 
3 
8.45 
9.34 
7.19 
2.15 
3 
6.80 
9.56 
2.76 
6.80 
2 
3.90 
4.64 
3.17 
1.47 
29 
5.74 
Maximum per cent of oil 
Minimum per cent of oil 
