Therapeutic effects of polyphenols in fermented soybean and black soybean products

Abstract

Polyphenols are a group of bioactive compounds that act as natural antioxidant in plants. isoflavones and anthocyanins are two main groups of polyphenols that are found in soybean and black soybean, respectively. Fermented soybean products are consumed in eastern Asian countries for centuries. In these products, after fermentation the glycosides polyphenols are converted into aglycone form of them such as genistein and diadzein by the action of β-glucosidase enzyme of the microorganisms used in these processes. These conversions caused to enhance the bioavailability of these phenolic compound in human intestine leads to a higher beneficial and therapeutic effects such as anti-cancer, antiobesity, neuroprotective and antidiabetes. These health promoting effects arise from the antioxidant activity of these two types of polyphenols and also the estrogen like structure of isoflavones that result in their estrogenic activity in human body. This review provides an overview of the fermentation effect on the changes happened in the structure and composition of polyphenols in fermented soybean and black soybean products lead to an increase in the different therapeutic activity of them.

Keywords

• Isoflavones
• Soybean
• Black soybean
• Fermentation
• Estrogen
• Cancer