Widely targeted metabolomics analysis of enriched secondary metabolites and determination of their corresponding antioxidant activities in Elaeagnus angustifolia var. orientalis (L.)Kuntze fruit juice enhanced by Bifidobacterium animalis subsp. Lactis HN-3 fermentation

•B.animalis subsp.lactis HN-3 was suitable strain for EOJ fermentation.•Antioxidant capacities of EOJ were increased by Bifidobacteria fermentation.•Less-active bioconjugates of EOJ were decreased by Bifidobacteria fermentation.•High bioactive free form compounds were increased by Bifidobacteria fermentation.•Deglycosidation and demethylation were occurred during fermentation process.