They were removed, dehulled and dried in the oven at 50 C for 24 h after
which they were ground into flour in an electric grinder. The
flour was sieved through 80 mesh sieve. The flour samples were
kept in airtight container before using. Packaging of flour
samples differs between sweet potato and soy bean, because
of the higher fat content in soy flour, so it is necessary to be
in airtight container.