Effect of molecular weight of chitosan on the formation and properties of zein-nisin-chitosan nanocomplexes

Abstract

This study evaluated the effect of molecular weight of chitosan (3 kDa,150 kDa, 400 kDa, and 600 kDa) on zein-nisin-chitosan nanocomplexes. The formation mechanism, physicochemical and antibacterial properties of the nanocomplexes (ZNC_0.3, ZNC₁₅, ZNC₄₀, and ZNC₆₀) were assessed. The nanocomplexes were characterized by DLS, ζ-potential, atomic force microscopy, scanning electron microscopy, circular dichroism, fourier transform infrared and UV-Vis spectroscopy. The results showed that the lowest molecular weight chitosan (LMWC, 3 kDa) formed nanocomplexes with nisin and zein structurally differed from the higher molecular weights chitosan (HMWC, >3 kDa). LMWC was doped on the surface of the nanocomplexes. HMWC linked and formed a network to adsorb zein and nisin. The antibacterial activity against Staphylococcus aureus showed that the minimum inhibitory concentration of ZNC_0.3, ZNC₁₅, ZNC₄₀, and ZNC₆₀ was 7.0625, 14.125, 14.125, and 28.25 μg/mL. ZNC_0.3 could be a suitable nisin delivery system for its high encapsulation efficiency (85.38%) and antibacterial properties.

Keywords: Acetic acid (Pubchem CID: 176); Agar (pubchem CID: 71571511); Antibacterial; Chitosan; Chitosan (Pubchem CID: 71853); Disodium hydrogen phosphate (Na(2)HPO(4), Pubchem CID: 24203); Ethanol (Pubchem CID: 702); Glucose (Pubchem CID: 5793); Hydrochloric acid (HCL, Pubchem CID: 71853); Molecular weight; Nisin; Nisin (Pubchem CID: 137698363); Potassium bromide (KBr, Pubchem CID: 253877); Sodium chloride (NaCl, Pubchem CID: 5234); Tryptone (Pubchem CID: 6579); Tween 20 (Pubchem CID: 443314); Zein; Zein (Pubchem SID: 135291755).