Ultrasonic-assisted foam fractionation for recovering bovine serum albumin from aqueous solution: Structure and function evaluation

•Ultrasound wave was used to strengthen BSA recovery by foam fractionation.•Interfacial adsorption of BSA molecules was improved by ultrasonic treatment.•Ultrasonic treatment can prevent the oxidation of free sulfhydryl groups in BSA.•Ultrasound wave can inhibit BSA aggregates formation in foam fractionation.•Ultrasonic-assisted foam fractionation can maintain functional property of BSA.