Isoflavone profiles of soymilk as affected by high-pressure treatments of soymilk and soybeans

High hydrostatic pressure was applied to hydrated soybeans (100–700 MPa, 25 °C) and soymilk (400–750 MPa; 25 and 75 °C) to assess its effect on isoflavone content, profile and water-extractability. Neither pressure level nor initial treatment temperature affected soymilk isoflavone content. However, combined pressure and mild thermal treatment modified the isoflavone distribution. At 75 °C, the isoflavone profile shifted from malonylglucosides toward β-glucosides, which was correlated to the effect of adiabatic heating. When pressure was applied to the hydrated soybeans, the soymilk isoflavone concentration varied between 4.32 and 6.06 μmol/g. The content of protein decreased and fat increased in soymilks prepared from pressurized soybeans with increasing pressure level.