Soy protein isolate (SPI) and soy protein concentrate (SPC) are largely used in bakery, confectionary, meat and beverage products. Isoflavones present in soybeans products can undergo changes in quantity and profile depending on the processing conditions. The objective of this work was to conduct mass balance studies of isoflavones and protein during the processing of SPI and SPC (acid and alcohol leach). The majority of isoflavones present in the raw material is lost in the supernatants (90% for SPC treated with alcohol, 52% for SPI and 47% for SPC treated with acid). Total concentration of isoflavones was 652µg/g for SPI, 838µg/g for SPC (acid leach), and only 147µg/g for SPC (alcohol leach). There were no changes in the profile of isoflavones in this last process, whereas in the previous two, the amount of malonyl glycosides decreased while the total amount of beta-glycosides and aglucones significantly increased.
isoflavones; mass balance studies; soy protein isolate; soy protein concentrate
