Laboratory of Food Chemistry and Biochemistry, and Leuven Food Science and Nutrition Research Centre (LFoRCe), KU Leuven, Kasteelpark Arenberg 20, B-3001 Leuven, Belgium.
Food Res Int. 2024 Nov;195:114977. doi: 10.1016/j.foodres.2024.114977. Epub 2024 Aug 23.
Maize zein based nanoparticles (ZNPs) can have applications as food dispersion stabilizers. It has not been documented to what extent the used zein isolation method and conditions thereof impact the structure and functionality of nanoparticles (NPs) based thereupon. Here, zein extracted from maize flour on lab scale (LS-zein) was compared with a commercial zein powder (CS-zein). On a dry matter basis, CS-zein contained 96.5% protein, while LS-zein contained 74.5% protein, 12.7% lipid, 2.9% ash, and a residual fraction, likely starch remnants. SE-HPLC analysis showed that 27.8% of CS-zein protein occurred in an aggregated and insoluble form, while LS-zein mainly contained mono-/dimeric proteins but also approximately 30% hydrophilic peptides. These differences resulted in notably different behavior in the functionality of ZNPs based on CS- and LS-zein (CS-ZNPs and LS-ZNPs, respectively) produced via liquid antisolvent precipitation. CS-ZNPs had poor foaming properties regardless of the pH, in line with their low interfacial dilatational moduli (12.9-15.0 mN/m). The foaming properties of LS-ZNPs were notably better. The high LS-ZNP foam stability (FS) at pH 8.0 and 10.0 was attributed to electrostatic repulsive effects between interfaces of adjacent air bubbles due to the adsorption of peptides and to synergistic protein-lipid interaction effects at the air-water interface. The LS-ZNP FS at pH 4.0 was low despite a high interfacial dilatational modulus (52.6 mN/m). It is hypothesized that intact LS-ZNPs in the liquid thin films between gas bubbles negatively affect FS by a bridging de-wetting effect. Overall, it can be concluded that the (partial) co-isolation of lipids with zein may positively influence foaming properties of NPs based thereupon, while extensive zein purification as applied in industrial zein isolation leads to (partial) zein aggregation and overall low foaming capacity of the obtained CS-ZNPs.
基于玉米醇溶蛋白的纳米颗粒（ZNPs）可用作食品分散稳定剂。目前尚不清楚所使用的醇溶蛋白分离方法及其条件会在何种程度上影响基于该方法的纳米颗粒（NPs）的结构和功能。在这里，我们比较了实验室规模提取的玉米醇溶蛋白（LS-zein）和商业玉米醇溶蛋白粉末（CS-zein）。基于干物质，CS-zein 含有 96.5%的蛋白质，而 LS-zein 含有 74.5%的蛋白质、12.7%的脂质、2.9%的灰分和残余部分，可能是淀粉残留物。SE-HPLC 分析表明，27.8%的 CS-zein 蛋白以聚集和不溶的形式存在，而 LS-zein 主要含有单/二聚体蛋白，但也含有约 30%的亲水肽。这些差异导致基于 CS-和 LS-zein（CS-ZNPs 和 LS-ZNPs）的 ZNPs 的功能表现明显不同，这两种 ZNPs 是通过液相抗溶剂沉淀法制备的。CS-ZNPs 无论 pH 值如何，起泡性能都很差，这与它们的界面扩张模量低（12.9-15.0 mN/m）一致。LS-ZNPs 的起泡性能明显更好。在 pH 值为 8.0 和 10.0 时，LS-ZNP 泡沫稳定性（FS）高，这归因于相邻气泡界面之间由于肽的吸附而产生的静电排斥效应，以及在气-水界面处蛋白质-脂质协同相互作用的影响。尽管界面扩张模量（52.6 mN/m）较高，但在 pH 值为 4.0 时 LS-ZNP 的 FS 较低。据推测，在气泡之间的液体薄膜中完整的 LS-ZNPs 通过桥接去湿作用对 FS 产生负面影响。总体而言，可以得出结论，（部分）与醇溶蛋白共分离的脂质可能会对基于该方法的 NPs 的起泡性能产生积极影响，而工业醇溶蛋白分离中应用的广泛醇溶蛋白纯化会导致（部分）醇溶蛋白聚集和获得的 CS-ZNPs 的整体起泡能力低。
