Ougan juice debittering using ultrasound-aided enzymatic hydrolysis: Impacts on aroma and taste

•Sonication further lowered bitterness of enzymatically hydrolyzed Ougan juice.•Sonication improved flavor of enzymatically hydrolyzed Ougan juice.•Sonication markedly enhanced glycosidic hydrolases activities from A. niger.•Sonication markedly weakened CO bonds of naringin in Ougan juice.•Improved enzyme activities and substrate structure facilitated bitter compounds degradation.