Im. Vasconcelos et al., COMPOSITION, TOXIC AND ANTINUTRITIONAL FACTORS OF NEWLY DEVELOPED CULTIVARS OF BRAZILIAN SOYBEAN (GLYCINE-MAX), Journal of the Science of Food and Agriculture, 75(4), 1997, pp. 419-426
Five different recently released Brazilian soybean cultivars (Bays, BR
-10, Rio Balsas, Serido and Tropical) were compared for their proximat
e analyses and presence of antinutritional or toxic factors. As expect
ed, the seeds are rich in proteins, varying from 360.7 to 485.4 g kg(-
1) flour, and they also have a high amount of fat (from 183.0 to 215.3
g kg(-1) flour). Crude extracts from seeds of Bays, BR-10, Serido and
Tropical were highly toxic to mice within 1-12 h, depending on the ad
ministration route (intraperitoneal, intramuscular or subcutaneous) an
d dose used while Rio Balsas was not. These acute effects were very si
milar to those produced by the soytoxin, a neurotoxin that has been re
cently purified from the commercial soybean sold in Brazil. The amount
of trypsin inhibited in the presence of crude extracts ranged from 28
.5 to 62.5 g kg(-1) flour. Urease was also present and the seed lectin
agglutinated preferentially rabbit erythrocytes. A heat treatment at
92 degrees C for 1 min destroyed completely the toxic activity while t
he haemagglutinating and trypsin inhibitor activities were abolished w
ithin 5 min. At these conditions urease was still active. Due to its h
igh protein content, lack of soytoxin, and low levels of trypsin inhib
itor, lectin, and urease it is suggested that Rio Balsas could be an a
lternative for breeding programmes aimed to improve the nutritional qu
ality of soybeans.