Correlation and in vitro mechanism of bactericidal activity on E. coli with whey protein isolate during ultrasonic treatment

Objective: This study aimed to investigate correlation and in vitro mechanism of bactericidal activity on E. colt with whey protein isolate (WPI) during ultrasonic treatment. Methods: The structural changes of WPI under ultrasonic field were studied by amino-acid analyzer, circular dichroism, SDS-PAGE, and spectrophotometer. Results: With the increasing of WPI concentration added during ultrasonic treatment, the survival rate of E. coli increased. The influence of WPI on bactericidal activity under ultrasonic treatment might due to the change of tertiary and higher level structures, not by the primary structure, and had little relation with secondary structure. Conclusion: The influence of WPI on bactericidal activity during ultrasonic treatment might due to the change of the tertiary structure and higher level structures.