Insight into the effect of 4-hydroxy-2,5-dimethyl-3(2H)-furanone on the changes of off-flavors in the preparation of soy protein isolate: Potential mechanisms of their reduction.

The effect of incorporating 4-hydroxy-2,5-dimethyl-3(2H)-furanone (furaneol) during soy protein isolate (SPI) preparation on off-flavor compounds was investigated. Sensory evaluation revealed that furaneol addition effectively reduced undesirable attributes such as grain husk, grassy, raw bean, tofu and oil oxidation, with the most significant decrease at 2 mg/L. Flavor analysis confirmed a significant reduction in both the variety and amount of off-flavors. The release kinetics study revealed a significant increase in the release rate of off-flavors like hexanal at 70 °C after furaneol addition, suggesting its role in promoting off-flavor release. In a simulated system, the headspace concentrations of hexanal, heptanal, nonanal and (E,E)-2,4-decadienal were significantly higher after furaneol addition compared to the control. Molecular docking further demonstrated that furaneol competitively binds to the binding site of hexanal. This study introduces an innovative solution to the beany flavor issue in the soy protein industry, promoting the wider application of soy protein products.