Zamani Zahra, Razavi Seyed Mohammad Ali, Nishinari Katsuyoshi
Center of Excellence in Native Natural Hydrocolloids of Iran, Ferdowsi University of Mashhad, PO Box: 91775-1163, Mashhad, Iran.
Center of Excellence in Native Natural Hydrocolloids of Iran, Ferdowsi University of Mashhad, PO Box: 91775-1163, Mashhad, Iran.
Int J Biol Macromol. 2025 Sep;322(Pt 1):146622. doi: 10.1016/j.ijbiomac.2025.146622. Epub 2025 Aug 6.
This study focused on understanding the stabilization mechanism of water-in-water (W/W) emulsions formulated using three biological macromolecules: basil seed gum (BSG, an anionic polysaccharide), waxy corn starch (WCS), and high-pressure-treated waxy corn starch (HWCS). For this purpose, the steady shear, small-amplitude oscillatory shear (SAOS), and large-amplitude oscillatory shear (LAOS) rheological properties of the W/W emulsions were investigated in detail. The results indicated that increasing the concentration of WCS/HWCS (up to 2 wt%) led to a significant increase in the elastic modulus (G'), with the 0.2 % BSG + 2 % HWCS emulsion, showing the highest G' (0.790 Pa) and complex viscosity (η = 0.140 Pa·s) at 1 Hz. The extent of nonlinearity, whether elastic or viscous, decreased with increasing WCS and HWCS concentrations, whereas shear thickening and strain hardening increased. The steady shear rheological behavior fitted well to the Cross model (R > 0.99), revealing significant shear-thinning characteristics, particularly at higher starch concentrations. Additionally, the Cross model showed that the zero-shear viscosity (η₀) increased from 1.899 Pa.s in BSG + 0.5 % HWCS to 26.072 Pa.s in BSG + 2 % HWCS, confirming a robust internal structure and greater flow resistance. The findings confirmed that BSG, in combination with WCS or HWCS at specific concentrations, effectively stabilized W/W emulsions for up to 14 days without phase separation. This stability can be attributed to the high zero-shear viscosity, strong shear-thinning, and robust structural integrity of these natural macromolecules.
本研究聚焦于理解使用三种生物大分子制备的水包水（W/W）乳液的稳定机制，这三种生物大分子分别为罗勒籽胶（BSG，一种阴离子多糖）、糯玉米淀粉（WCS）和高压处理的糯玉米淀粉（HWCS）。为此，详细研究了W/W乳液的稳态剪切、小振幅振荡剪切（SAOS）和大振幅振荡剪切（LAOS）流变特性。结果表明，增加WCS/HWCS的浓度（高达2 wt%）会导致弹性模量（G'）显著增加，其中0.2% BSG + 2% HWCS乳液在1 Hz时显示出最高的G'（0.790 Pa）和复数粘度（η = 0.140 Pa·s）。随着WCS和HWCS浓度的增加，弹性或粘性的非线性程度降低，而剪切增稠和应变硬化增加。稳态剪切流变行为与Cross模型拟合良好（R > 0.99），显示出显著的剪切变稀特性，特别是在较高淀粉浓度下。此外，Cross模型表明，零剪切粘度（η₀）从BSG + 0.5% HWCS中的1.899 Pa·s增加到BSG + 2% HWCS中的26.072 Pa·s，证实了其强大的内部结构和更大的流动阻力。研究结果证实，BSG与特定浓度下的WCS或HWCS组合，可有效稳定W/W乳液长达14天而不发生相分离。这种稳定性可归因于这些天然大分子的高零剪切粘度、强剪切变稀和强大的结构完整性。
