The Cyclic Peptide Cyclo-zp80r Controls and Replication in Non-Concentrated (NFC) Orange Juice: Antibacterial Effects and Mechanisms of Action.

The market for non-concentrated (NFC) orange juice is increasing rapidly due to consumer demand for nutrients and flavor. However, it encounters challenges in microbial safety, particularly from and This study aimed to exploit a bio-preservative for NFC orange juice. Results showed that the cyclic peptide cyclo-zp80r had good antibacterial activity, with minimum inhibitory concentration values of 2-8 μM against and . It exhibited bactericidal action against and bacteriostatic action against at a concentration of 128 μM. This study explored the effect of cyclo-zp80r on the pathogenicity of and . The mortality rate of exposed to these pathogens in NFC orange juice decreased from 100% to 60% after cyclo-zp80r treatment, surpassing the effectiveness of nisin. Cyclo-zp80r exhibited depolarization effects on and . It increased outer membrane permeability and damaged the membrane structure of . Cyclo-zp80r also caused distinct morphological changes, mainly cell collapse in and localized bubble-like protrusions in . It induced reactive oxygen species production and DNA binding. The species diversity and abundance in NFC orange juice were also reduced by cyclo-zp80r, particularly in the genera , , , and . Additionally, cyclo-zp80r exhibited excellent stability at high temperature (121 °C, 5 min) and in fresh orange juice. These results suggest that cyclo-zp80r could be developed as an effective food bio-preservative.