不同电荷阴离子多糖对负载单宁酸的玉米醇溶蛋白纳米颗粒的稳定作用

Stabilization of Tannic Acid-loaded Zein Nanoparticles by Anionic Polysaccharides with Different Charges

摘要:

以反溶剂法制备负载单宁酸的玉米醇溶蛋白纳米颗粒（Tannic acid loaded zein nanoparticles，TZP），将TZP分散液按1:2体积比分散至pH 4.0的多糖溶液，研究带有不同表面电荷数的阴离子多糖海藻酸丙二醇酯（Propylene glycol alginate，PGA）、阿拉伯胶（gum Arabic，GA）、高酯果胶（High methoxy pectin，HMP）、低酯果胶（lowmethoxy pectin，LMP）对纳米颗粒稳定性的影响。结果表明，低浓度多糖使得颗粒表面电荷降低，导致纳米颗粒沉淀，其中PGA、GA、HMP稳定颗粒所需的最低浓度为0.055%（m/V），而LMP所需的最低浓度为0.022%（m/V）。TZP/多糖复合纳米颗粒随pH和NaCl稳定性的变化是由阴离子多糖的ζ-电位导致，电位较低的GA在pH 2.0、6.0、6.5及低浓度NaCl浓度时均会导致纳米颗粒沉淀，而电位最强的LMP在pH 2.0~8.0范围内均能够稳定纳米颗粒，在氯化钠浓度为30 mmol/L时颗粒发生沉淀。经冷冻干燥，TZP/LMP纳米颗粒得率可达95.10%，此时单宁酸负载率为88.97%，单宁酸含量为5.39%。该研究表明玉米醇溶蛋白/低酯果胶纳米颗粒可用于亲水性生物活性物质的包埋与输送，可望用于保健食品及医药行业。

Abstract:

Tannic acid-loaded zein nanoparticles (TZP) were fabricated by the anti-solvent method, and the TZP dispersion was dispersed into a polysaccharide solution with a pH of 4.0 at a volume ratio of 1:2. The effects of different anion-charged polysaccharides (propylene glycol alginate, PGA; gum Arabic, GA; high-methoxyl pectin, HMP; low-methoxyl pectin, LMP) on the stability of TZP were investigated. The results showed that the polysaccharide at a low concentration decreased the surface charge of particles, causing the precipitation of nanoparticles, with the minimum concentration required to stabilize the particles being 0.055% (m/V) for PGA, GA and HMP, and 0.022% (m/V) for LMP. The changes in the stability of TZP/polysaccharide composite nanoparticles with pH or NaCl were associated with the ζ-potential of anionic polysaccharides. GA with a lower potential led to the precipitation of nanoparticles at pH 2.0, 6.0 or 6.5 and a low NaCl concentration, whereas, LMP with the highest potential stabilized the nanoparticles in the pH range of 2.0~8.0, with the particles precipitating at a sodium chloride concentration of 30 mmol/L. After freeze-drying, the yield of TZP/LMP nanoparticles reached 95.10% with the tannic acid loading rate as 88.97% and tannic acid content as 5.39%. The research showed that zein/LMP nanoparticles could be used for encapsulating and delivering hydrophilic bioactive compounds, which are expected to be used in the functional food or pharmaceutical industries.