Bioaccessibility and Bioavailability of Soybean Isoflavones: An In Vitro Study

Soybean (Glycine max [L.] Merr.), one of the top 10 crops produced worldwide, is a significant dietary source of isoflavones. Understanding the bioaccessibility and bioavailability of soy isoflavones (SIs) is important fgor comprehending their various bioactivities in the human body. In vitro approaches can provide valuable insights into the bioavailability of SIs across food matrices and their step-by-step digestive mechanisms. This review focused on evaluating reports that employ invitro methods to study the bioavailability of SIs, using human-simulated gastrointestinal digestive system models and the Transwell system with Caco-2 cell monolayers. Specifically, this review discusses how the molecular structures of SIs influence their bioaccessibility and bioavailability. The differences in bioaccessibility and bioavailability of SI aglycones and their conjugated SIs indicate that the molecular structure is a critical factor influencing the bioactivities of SIs. This review provides important information for evaluating and understanding the physiological effects of soybean or SI-containing foods.