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 (TG_x 923 ? 2^EN, TG_x 1019 ? 2^EN and TG_x 1497 ? 1^D), 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. TG_x 923 ? 2^EN possessed higher crude protein contents and lower amounts of trypsin inhibitor, polyphenol and phytic acid compared with TG_x 1019 ? 2^EN or TG_x 1497 ? 1^D. 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 TG_x 923 ? 2^EN and casein, indicating the nutritional superiority of this soybean line compared with TG_x 1019 ? 2^EN and TG_x 1497 ? 1^D. © 2002 Society of Chemical Industry