Enhancement of the antioxidant capacity of soy whey by fermentation with Lactobacillus plantarum B1–6

• Lactobacillus plantarum B1–6 was able to ferment soy whey.
• Antioxidant properties were evaluated in vitro using several methods.
• Fermentation enhanced antioxidant activities, total phenolic and isoflavone aglycone contents of soy whey.
• Fermented soy whey showed higher protection effects for damaged DNA.
• Fermentation process allows to obtain a nutraceutical and functional soy beverage.

The antioxidant capacity of fermented soy whey (FSW) was investigated in order to find out their nutraceutical potential, and unfermented soy whey (USW) was used as a control. FSW was prepared using Lactobacillus plantarum B1–6 as a starter. The effects of fermentation on soy whey in terms of total phenolic content (TPC), antioxidant activities and DNA damage protection were investigated. The antioxidant activities of FSW and USW were determined by different standard methods. The results showed FSW extract compared to USW possessed more TPC and isoflavone aglycone contents, and had higher ABTS radical scavenging activity, ferric reducing antioxidant power, reducing power, hydroxyl radical scavenging activity and superoxide radical scavenging activity. Additionally, FSW extract exhibited greater protection against oxidative DNA damage induced by Fenton's reagent. The results suggested that FSW with enhanced antioxidant capacity could provide a functional soy beverage to contribute to the health and nutritional status improvement of consumers.