20 
BULLETIN 1471, U. S. DEPARTMENT OF AGRICULTURE 
of flaxseed of different shades of color. But it should be pointed 
out that as a rule foreign-grown seed, a class which usually is a 
rich brown color, contains on the average a greater quantity of oil 
than the domestic crop. On the other hand, fiber flaxseed is also 
deep brown in color, but contains on the average 1 to 3 per cent less 
oil than either the domestic-grown seed or the foreign-grown crop. 
RELATION BETWEEN SIZE OF FLAXSEED AND OIL CONTENT OF SEED 
Large plump flaxseed kernels have generally been considered 
to contain more oil than seeds smaller in size. Rabak (?) reports that 
small-seeded flax varieties consistently contained a smaller quantity 
of oil than the varieties having larger seed. Birchard (2) also 
reported that plump, fully matured seeds contained more oil than 
did smaller seeds. 
In connection with the other investigations reported in this bulle- 
tin, a comparison was made of the plumpness of flaxseed and its 
oil content. As a measure of plumpness, the weight of 1,000 average 
kernels was taken. To afford a fair comparison, the figures for 
both (weight per 1,000 kernels and percentage of oil) are given 
on the same basis — moisture free. The results of these tests as 
given in Table 14, show that there is a gradual increase in oil content 
as the kernels grow larger. 
Table 14. — Relation of size of kernel and oil content 
Number of samples analyzed 
Weight per 
1,000 kernels 
Average 
oil 
content 
Maxi- 
mum oil 
content 
Mini- 
mum oil 
content 
Range in 
oil con- 
tent 
I__ 
Grams 
3. 50 to 3. 59 
3. 60 to 3. 69 
3. 70 to 3. 79 
3. 80 to 3. 89 
3. 90 to 3. 99 
4. 00 to 4. 09 
4. 10 to 4. 19 
4. 20 to 4. 29 
4. 30 to 4. 39 
4. 40 to 4. 49 
4. 50 to 4. 59 
4. 60 to 4. 84 
Per cent 
37.67 
39.46 
38.68 
39.27 
39.73 
39.78 
40.02 
41.18 
41.33 
41.19 
40.21 
40.84 
Per cent 
37.67 
40.17 
41.00 
40.77 
41. 12 
41.13 
41.38 
42.26 
41.85 
41.85 
40.21 
40.89 
Per cent 
37.67 
37.53 
37.17 
37.71 
37.71 
39.39 
39.98 
40.81 
40.43 
40.43 
40.21 
40.80 
Per cent 
0.00 
2 
2.64 
4__ 
3.83 
8__ - 
3.06 
9 
3.41 
8 _ 
1.74 
8 
1.40 
3 
1.45 
5 
1.42 
5 
1.42 
1 
.00 
2 
.09 
The frequency with which a larger percentage of oil was found 
occurred more often in the large, plump seeds. However, it must 
be pointed out that the relationship is not specific and that small 
plump seeds often contain as great a percentage of oil as a sample 
containing very large kernels. 
These tests would seem to bear out the point that, whereas in the 
same sample of flaxseed there may be a difference in the oil content 
of kernels caused by size of kernel, it does not necessarily hold that 
all large kernels of flaxseed from different lots of seed will have a 
high oil content. 
Eleven samples of flaxseed secured from different lots of seed 
varying in size and plumpness were studied to find if there is any 
positive relationship between the specific gravity of the flaxseed ker- 
nels and the percentage of oil in the samples. The data found from 
this study are given in Table 15. The kernels having the lowest 
