Preparation and characterisation of soya milk enriched with isoflavone aglycone fermented by lactic acid bacteria combined with hydrothermal cooking pretreatment

Summary A fermented soya milk (FSM) enriched with isoflavone aglycone (FSM-SPIA) was prepared from heated soya protein isolate (SPI)-isoflavone complex. After 48 h of fermentation, FSM-SPIA contained higher contents of living bacteria, free amino acids and aglycone compared with the FSM of SPI (FSM-SPI) and the FSM of SPI-isoflavone complex (FSM-Mix). In the in-vitro digestion experiment, FSM-SPIA showed higher antioxidant capacity and isoflavones (ISO) bioavailability than FSM-SPI and FSM-Mix. This was likely due to the soya milk containing a higher level of amino acid, peptides and the presence of soya bean isoflavone. The improved protein digestibility, the interaction and binding ability between proteins and ISO may affect the properties of the protein and the fermented products. The FSM enriched with isoflavone aglycone can be used as a functional fermented drink, as well as an auxiliary food for menopausal women during a specific pathological period.