Seed weight and moisture and protein content were determined
as described previously (Yang & James, 2013). Briefly, seed
weight (g/100 seeds) was determined by weighing one hundred
raw soybean seeds. The moisture and solid content in the seed
and soymilk were determined by placing weighed samples of
ground soybeans (3 g) or soymilk (10 g) in an oven at 105 C
for 24 h. The dried soymilk was then ground and the nitrogen content
for dried soymilk and dried ground seed was analysed using
LECO TrueSpec CHN analyser (Leco Corp., St Joseph, MI, USA). The
total crude protein content was obtained by multiplying total
nitrogen content with a conversion factor of 6.25.