Development of water-soluble zein colloid particles and in situ antibacterial evaluation by multiple headspace extraction gas chromatography

In this work, water-soluble zein/sodium caseinate (SC) nanoparticles were prepared as a delivery system of antimicrobials through anti-solvent procedure. Two model antimicrobials (nisin and thymol) were coencapsulated into zein particles by different interaction. Release properties indicate that zein colloid particles can be used not only in neutral food but also in acidic foods. It is worth mention that the release of thymol was delayed simply by adding nisin. To investigate the antimicrobial properties of zein/SC particles, Escherichia coli and Bacillus subtilis, Listeria monocytogenes were selected as gram-negative and gram-positive indicator bacteria. CO, produced by incubated germs was detected by headspace gas chromatography. Long-term effective antimicrobial activities of zein particles in Luria broth was attained by burst release of nisin and slowly sustained release of thymol. Synergistic antimicromibial properties against L. monocytogenes of thymol and nisin loaded by zein/SC particles in milk were also observed. The antimicrobial property of zein/SC particles could enhance microbial safety of food, giving this delivery system promising applications in food industry. (C) 2021 Beijing Academy of Food Sciences. Production and hosting by Elsevier B.V. on behalf of KeAi Communications Co., Ltd.

Automated summary

Water-soluble zein/sodium caseinate nanoparticles were prepared as a delivery system of antimicrobials, successfully encapsulating nisin and thymol. The nanoparticles demonstrated excellent antimicrobial properties, showing potential applications in both neutral and acidic foods, with synergistic antimicrobial effects against various bacteria.