Disclosed is a soy protein composition, comprising; a mixture of 7S and 2S
rich protein fraction having a .beta.-conglycinin content greater than
about 45% by weight on a moisture free basis, and having an a content of
from about 15% up to about 30% by weight on a moisture free basis, an
.alpha.' content of from about 22% up to about 40% by weight on a
moisture free basis and a .beta. content of from about 5% up to about 18%
by weight on a moisture flee basis: a glycinin content of from about 13%
up to about 45% by weight on a moisture free basis; wherein a weight
ratio of .beta.-conglycinin to glycinin in the soy protein composition is
from about 1 up to about 6; and wherein a TIU/mg content in the soy
protein composition is from about 50 up to about 125 before denaturation
and from about 5 up to about 30 after denaturation. Also disclosed is a
process for preparing a mixture of 7S and 2S rich protein fraction having
a .beta.-conglycinin content greater than about 45% by weight on a
moisture free basis, and having an a content of from about 15% up to
about 30% by weight on a moisture free basis, an .alpha.' content of from
about 22% up to about 40% by weight on a moisture free basis and a .beta.
content of from about 5% up to about 18% by weight on a moisture free
basis; a glycinin content of from about 13% up to about 45% by weight on
a moisture free basis; wherein a weight ratio of .beta.-conglycinin to
glycinin in the soy protein composition is from about 1 up to about 6;
and wherein a TIU/mg content in the soy protein composition is from about
50 up to about 125 before denaturation and from about 5 up to about 30
after denaturation, the process comprising: in a first precipitation,
precipitating a soybean 11S-rich globulin fraction from a dispersion of
soy protein in a liquid medium, thereby forming a first supernatant
liquid medium, separating said soybean 11S-rich globulin fraction from
said first supernatant liquid medium, in a second precipitation,
precipitating a mixture of a soybean 11S-rich globulin fraction and a
soybean 7S-rich globulin fraction from said first supernatant liquid
medium, thereby forming a second supernatant liquid medium, and in a
third precipitation, precipitating a mixture of 7S-rich globulin fraction
and 2S-rich fraction from said second supernatant liquid.
