Abstract: In order to enrich nutrients in tartary buckwheat residue by liquid-state fermentation, the contents of protein, crude fat, minerals, crude fiber, ash, total flavonoids, total phenolics, amino acid composition and fatty acid composition in Xinong 9940 tartary buckwheat flour and its residue left after being subjected to liquid-state fermentation were analyzed and the antioxidant activity was evaluated by total reducing capacity, 1,1-dipheny1-2-picryl-hydrazyl (DPPH) radical scavenging, 2,2’-azinobis-(3-ethylbenzthiazoline-6-sulphonate) (ABTS) radical scavenging assays. The results showed that protein, crude fat, ash, crude fiber, minerals contents of buckwheat residue increased significantly after fermentation. Furthermore, liquid-state fermentation did not change the amino acid and fatty acid composition of buckwheat flour. The total phenolic content of tartary buckwheat residue was 1 343.22?mg/100 g, which was significantly higher than that of buckwheat flour (559.76?mg/100 g), and the total flavonoids content was 2 186.06?mg/100 g, which was significantly lower than that of buckwheat flour (2 464.10?mg/100 g). Moreover, the contents of the flavonoids rutin and quercetin significantly decreased after fermentation. However, the total reducing capacity, DPPH radical scavenging capacity, and ABTS+· scavenging ability were significantly higher than those of tartary buckwheat flour. These results indicated that tartary buckwheat residue showed stronger antioxidant after fermentation.

Key words: tartary buckwheat flour, fermentation, polyphenols, flavonoids, antioxidant activity