Solid state fermentation with Cordyceps militaris SN-18 enhanced antioxidant capacity and DNA damage protective effect of oats (Avena sativa L.)

• Solid state fermentation (SSF) with Cordyceps militaris was used to produce fermented oats.
• SSF enhanced content of phenolics, avenanthramides and flavonoids, and antioxidant activities of oats.
• Fermented oats showed higher protection effects for damaged DNA.
• Acetone extract of fermented oats exhibited the strongest antioxidant activities.
• Fermented oats can be used as new nutraceuticals and functional foods for the food industry.

The aim of the present work was to investigate the effect of solid-state fermentation with Cordyceps militaris SN-18 on major antioxidant components, antioxidant activities and DNA damage protection of oats. Various solvents with different polarities were used to extract antioxidant components and ultra-high performance liquid chromatographic analysis was conducted to determine the major individual phenolic compounds of the oat samples. The results indicated that extraction yields, major phenolic compounds, antioxidant activities and DNA damage protection of oats were significantly (p < 0.05) enhanced by fermentation, and the acetone extract of fermented oats showed the strongest antioxidant activities. Analysis of extraction yields revealed that the bioactive principles associated with DPPH radical and ABTS⋅+ scavenging effect, reducing power was most efficiently extracted from fermented oats using water. Additionally, fermented oat extracts demonstrated significantly (p < 0.05) greater protection against oxidative DNA damage than non-fermented samples. There was a strong correlation between the phenolic compounds and antioxidant activities. Thus, the present study showed that fermented oats with enhanced antioxidant capacity and DNA damage protection, which can be effective in the prevention of oxidative damage-induced disease, therefore serve as nutraceuticals and functional foods in health promotion.