The use of anti-soya globulin antisera in investigating soya digestion in vivo

Polyclonal antisera have been developed which recognise the soya globulins glycinin and beta-conglycinin. Their binding to proteolysed and processed g lobulins has been characterised with a view to using the antisera as probes to investigate the fate of soya globulins during digestion. Trypsinolysis reduced the immunoreactivity of beta-conglycinin but increased that of glyc inin by threefold, as determined by enzyme-linked immunosorbent assay (ELIS A). However, both antisera recognised trypsinolysis products poorly by immu noblotting. These data are consistent with the fact that the anti-glycinin antiserum was raised to digested glycinin and would therefore recognise bot h intact and proteolytic intermediates of glycinin. The latter would be dis rupted into component polypeptides by sodium dodecyl sulphate-polyacrylamid e gel electrophoresis and hence would only be present in the ELISA and not after blotting. The antibody preparations were used to investigate the fate of soya globulins during in vivo digestion of a processed soya ingredient in rats. Both glycinin and beta-conglycinin were digested rapidly, intact g lobulins disappearing from the gastrointestinal tract 3 h after dosing. Imm unoreactive globulins were found in gut contents and associated with gut ti ssues but appeared to be in a semi-intact form, probably comprising proteol ytic intermediates. This study demonstrates the usefulness of antibody meth ods in following the digestion of individual components in a complex mixtur e, such as is found in food. The availability of antibody preparations whic h recognise heat-stable epitopes will open the way for investigations into the effects of pre-treatments, such as cooking, which are pertinent to huma n consumption of legumes. (C) 2000 Society of Chemical Industry.