Nutritional preparations of soy (Glycine max (L.) Merr.) have gained interest in western countries as an alternative to hormonal
therapy in the treatment of menopausal problems such as hot flushes. The active compounds
responsible for this are the present isoflavones, mainly genistin, daidzin and glycitin
which show a weak estrogenic activity and are therefore called phytoestrogens.
In the present study, FTIR-ATR spectroscopy has been applied for the characterization
and identification of the main isoflavones in soy based nutritional preparations available
in German pharmacies. Informations about the functional groups and the chemical composition
could be obtained which makes FTIR analysis expedient for a simple and non-destructive
quality control.
Moreover, using the partial least square (PLS) analysis multivariate calibration models
were employed. This made estimations about the amount of the individual isoflavones
and the total isoflavone content possible. The results of these infrared spectroscopy
studies in combination with multivariate calibration showed the potential for production
monitoring by pharmaceutical manufacturers and public supervisory authorities.
