The Preparation,Mechanism And Application Studies Of Natamycin Nanodispersion System

Natamycin is a safe,efficient and widely natural antifungal agent,but its poor solubility and stability limit its application,so it is very important to find a carrier system of natamycin.Zein has been widely used as carrier materials for active ingredients in recent years due to its low cost,unique solubility,good biocompatibility and low carbon degradation.In this study,the method of embedding natamycin in zein nanoparticles was proposed to improve the water dispersibility and light stability of natamycin,providing a new method for the dispersant of natamycin.The preparation of natamycin-zein nanoparticles(NZ-Nps)by anti-solvent method were investigated.The interaction mechanism between natamycin and zein were studied.Research further with carboxymethyl chitosan(CMC)for nanoparticles of stabilizers,and the effect resolubilization of composite dispersant was better.The preparation conditions and stability of the colloidal system were investigated.At last,the effect of the new compound dispersant on the preservation of blueberries under light was studied.The main works and conclusions of this research are following:Firstly,the dispersions of natamycin-zein nano particles(NZ-Nps)were prepared by anti-solvent method.The effects of preparation parameters on the colloidal properties of NZ-NPs and the ratio of natamycin to zein on the encapsulation efficiency were studied and the natamycin photostability of NZ-NPs was investigated.The results showed that when the concentration of zein and ethanol solutions were 1.2mg/mL and 70%respectively,the properties of NZ-NPs about average diameter,potential and PDI were 310±10nm,-22.50±5mV and 0.15±0.05 respectively.When the concentration of zein and natamycin were 1.2 mg/mL and 0.1 mg/mL respectively,the NZ-NPs encapsulation efficiency reached to 68.27%.The bacteriostatic experiment showed that NZ-NPs had more effective bacteriostasis than natamycin aqueous solution,indicating that NZ-NPs could improve the solubility of natamycin.Degradation experiments show that NZ-NPs can improve the stability of natamycin under ultraviolet light.The interaction between natamycin and zein was studied.The fluorescence quenching experiment showed that the quenching mechanism of natamycin to zein was static fluorescence quenching,and the interaction between molecules was mainly through hydrophobic interaction.The 1H-NMR show the chemical shift were increased that natamycin of H2,H4 ·and serine residues in the zein,which maybe be formation of hydrogen bonding.2H-NMR spectra showed cross signal between the hydrophobic carbon chain of natamycin and leucine residue in zein,which further proves the existence of hydrophobic interaction.Molecular dynamics showed that hydrogen bonds were formed between Nt-C9-OH and Zein-Pro 122-O,Nt-C6'-H and Zein-Gln119-NH,and hydrogen bonds were also important forces for the formation of the complex.zein composite dispersion(NZC-Nps)was prepared used carboxymethyl chitosan as a stabilizer.The stability of two dispersions(NZ-NPs and NZC-Nps)at different pH,ionic strength and storage time was studied.The average diameter of NZC-Nps was always between 200 and 300 nm during 30 days storage,while the particle szie of NZ-NPs was reached to 3 545 nm at 15 days,indicating that NZC-Nps had better stability.The scanning electron microscopy structure show the dispersed freeze-dried particles were nanometer level of spherical structure.The NZC-Nps freeze-dried powder had a better re-solubility and the release effect was obvious.A theoretical model was proposed for the stability of NZC-NPs dispersion system.Finally,the results showed that the NZC-Nps dispersant had a good effect on the preservation of blueberry under 800 Lx light.The weight loss rate,soft fruit rate and decay rate of blueberry treated with NZC-Nps were lower than control group,and the total soluble solids of blueberry was not obvious changed.The above research shows that the NZC-Nps dispersion system can be applied to the preservation of blueberries and provides a reference value for the application of natamycin dispersant in fruits and vegetables.