Processing effects on the nutritive value of soybean seeds and products
Antunes, P.L.; Sgarbieri, V.C.
Archivos Latinoamericanos de Nutricion 27(1): 33-47
1977
ISSN/ISBN: 0004-0622 PMID: 562138 Document Number: 119623
The effects of processing on the nutritive value of soya bean proteins were studied on products prepared in the laboratory and soya beans and meals collected from an industrial plant at different stages of processing. For total destruction of trypsin inhibitor in unsoaked beans, beans soaked in water for 12 h and dehusked beans soaked for 12 h, boiling in water for 25, 15 and 7.5 min, respectively, was necessary; for total destruction in a water extract it was necessary to heat for 30 min in an autoclave at 121 deg C. Haemagglutinin was inactivated by heating unsoaked beans for 45 min in boiling water but a soya bean extract required heating for 7.5 min only. Lysine availability in soya beans increased with heating in boiling water for up to 30 min but with further heating availability decreased. Protein efficiency ratio (PER) of 4 laboratory preparations and of 4 industrial byproducts was estimated with groups of male weanling Wistar rats given diets with 10% protein for 28 days. PER ranged from 1.30 for soya bean milk residue heated for 10 min at 110 deg to 2.66 for defatted soya bean flour heated for 15 min at 97 deg . There was no relation between trypsin inhibitor activity and PER value. Of 9 rats given a diet with crude ground soya beans 4 died within 28 days and the rest lost a mean 0.37 g daily.