Influence of proteolytic enzyme treatment on the changes in volatile compounds and odors of beef longissimus dorsi

•Excessive proteolysis during enzymatic tenderization generated bitter peptides.•Mild proteolysis by Fla and Bro helped to elevate the levels of volatiles and odors.•Excessive proteolysis by Pap and Pro K had a negative influence on flavors.•Liberation of amino acids was the most predominant factor that affects volatiles. Enzymatic tenderization is extensively applied in the meat industry, whereas its influence on meat flavor has seldom been evaluated. Proteinase K, papain, bromelain and Flavourzyme® were used to treat beef muscle, and the changes in volatile compounds and odors were subsequently analyzed. Proteolysis by proteinase K was found to elevate the average bitterness of the identified peptides by generating peptides with high Q values, whereas proteolysis by papain generated the highest level of amino acids. Enzymatic treatment by Flavourzyme and bromelain significantly elevated the levels of ketones and odors, whereas excessive proteolysis by papain and proteinase K largely reduced the levels of esters and aldehydes. The level of amino acids and degree of hydrolysis were found to be predominant factors that regulated the level of volatiles and odors. These results highlighted the huge influence of enzymatic tenderization on meat flavor, depending on degree of hydrolysis and cleavage pattern of applied proteases.