From the 1992 Hive and the Honey Bee, pp. 215-221:

Erickson and Herbert in 1980 ABJ 120, pp. 122-126 concluded:

1.  Soyflour should be fully toasted to remove trypsin inhibitors
2.  Soyflour should have a fast content about 7% if fed without pollen
3.  Soyflour should have a fat content of about 0.5%-1% if fed with 10-20%
pollen, as in pollen supplement
4.  Soyflour should have a high protein content (about 45-60%)

Expeller processing and solvent processing leave different amounts of fat
in the resulting product...it is presumably the fat content not presence of
contaminates that is important...

There is good in-depth information in the chapter cited.

Tom Sanford

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