Chemical composition and nutritional attributes of selected newly developed lines of soybean (Glycine max (L) Merr)

The chemical composition and nutritional properties of raw, autoclaved and boiled samples of three promising advanced breeding lines of soybean (TGx 923 − 2EN, TGx 1019 − 2EN and TGx 1497 − 1D), part of a larger collection evaluated in agronomic field trials in Nigeria, were investigated. Protein quality was evaluated using weanling albino rats fed diets which were formulated to supply 10% protein using soybean samples, with casein as a control. Raw seeds contained 35.6–42.4% crude protein, 8.9–9.8 mg iron per 100 g, 8.62–18.21 mg trypsin inhibitor g−1 and 2.25–6.15 mg phytic acid g−1 seed flour. TGx 923 − 2EN possessed higher crude protein contents and lower amounts of trypsin inhibitor, polyphenol and phytic acid compared with TGx 1019 − 2EN or TGx 1497 − 1D. Boiling proved more effective than autoclaving for reducing the levels of antinutrients and improving the protein quality of the beans, as shown by the higher values for weight gain, protein efficiency ratio (PER), net protein ratio (NPR) and true digestibility (TD) of boiled samples. There were no significant (p > 0.05) differences between the values obtained for PER, NPR and TD of diets containing boiled samples of TGx 923 − 2EN and casein, indicating the nutritional superiority of this soybean line compared with TGx 1019 − 2EN and TGx 1497 − 1D. © 2002 Society of Chemical Industry