Dual functional properties of enzymatically hydrolyzed dromedary milk proteins with improved antioxidant and antibacterial activity

Abstract

Keywords Dromedary milk has a proven outstanding history of being a nutrient-rich food. Camel milk possesses both medicinal and technological advantages, including antioxidant, antibacterial, and antiparasitic activities. The present investigation is proposed to assess the antibacterial ability and free radical scavenging capacity against Gram-negative bacteria of various enzyme-digested skimmed camel’s milk (SCM) using papain, pepsin, and trypsin at four hydrolysis times at one-hour intervals. An antibacterial growth assay was conducted to detect the antibacterial capacity of the generated various enzymatic camel milk hydrolysates. The results showed that the antibacterial activity of unhydrolyzed intact SCM displayed mild effect against Escherichia coli and no effect against Salmonella enteritidis . Pepsin-treated SCM hydrolysates after 3h hydrolysis significantly enhanced SCM antimicrobial activity against E. coli , and after 2h, hydrolysis produces SCM hydrolysates against Salmonella enteritidis. Pepsin and trypsin SCM-treated hydrolysates after 2h hydrolysis could completely abolish the survival growth rate of Salmonella enteritidis. Additionally, hydrolysates treated with papain SCM after 3 and 4 hours of hydrolysis showed a 100% ability to kill Salmonella enteritidis . Both DPPH method and ABTS assays were employed to evaluate antioxidants. Our findings demonstrated that all SCM hydrolysates gradually acquired strong antioxidant capacity after four hours of hydrolysis, with trypsin-treated hydrolysates having the highest values. The current work offered a great role of skimmed camel’s milk hydrolysates and the possibilities for using these hydrolysates as food natural preservatives.