This investigation showed that the total recovery of
isoflavones in tofu was as low as 36% (based on dry
matter) when compared with the amount present in raw
soybean cv. RCAT Angola (Table 2). However, the
recovery of isoflavones in the soy beverage was 54%. It
is apparent that each processing step in tofu manufacturing
contributes to the loss of isoflavones, resulting in
a considerable amount of isoflavones being lost in the
resultant by-products. Similar to the present results,
Wang and Murphy [17] observed recovery of total
isoflavones in traditional momem tofu as 33%. However,
recovery of isoflavones from soy beverage was
higher (67%) in the present study compared with that in
Wang and Murphy’ [17] study where it was only 36%.
The difference seems to result from the type of coagulant
used in tofu preparation. It is apparent from this
study that use of glucano delta lactone (GDL) as the
coagulant might be better and more efficient than
CaCO4 that was used in the previous study [17] in terms
of recovering isoflavones in tofu from soy beverage.