Parajuli Sanjiv, Hasan Mohammad Jahid, Ureña-Benavides Esteban E
Department of Biomedical Engineering and Chemical Engineering, The University of Texas at San Antonio, San Antonio, TX 78249, USA.
Materials (Basel). 2022 Sep 26;15(19):6673. doi: 10.3390/ma15196673.
Chitin nanocrystals (ChNCs) and cellulose nanocrystals (CNCs) have been recently used to stabilize emulsions; however, they generally require significant amounts of salt, limiting their applicability in food products. In this study, we developed nanoconjugates by mixing positively charged ChNCs and negatively charged CNCs at various ChNC:CNC mass ratios (2:1, 1:1, and 1:2), and utilized them in stabilizing soybean oil-water Pickering emulsions with minimal use of NaCl salt (20 mM) and nanoparticle (NP) concentrations below 1 wt%. The nanoconjugates stabilized the emulsions better than individual CNC or ChNC in terms of a reduced drop growth and less creaming. Oppositely charged CNC and ChNC neutralized each other when their mass ratio was 1:1, leading to significant flocculation in the absence of salt at pH 6. Raman spectroscopy provided evidence for electrostatic interactions between the ChNCs and CNCs, and generated maps suggesting an assembly of ChNC bundles of micron-scale lengths intercalated by similar-size areas predominantly composed of CNC. The previous measurements, in combination with contact angles on nanoparticle films, suggested that the conjugates preferentially exposed the hydrophobic crystalline planes of CNCs and ChNCs at a 1:1 mass ratio, which was also the best ratio at stabilizing soybean oil-water Pickering emulsions.
几丁质纳米晶体(ChNCs)和纤维素纳米晶体(CNCs)最近已被用于稳定乳液;然而,它们通常需要大量盐,这限制了它们在食品中的适用性。在本研究中,我们通过将带正电荷的ChNCs和带负电荷的CNCs以不同的ChNC:CNC质量比(2:1、1:1和1:2)混合来制备纳米共轭物,并将其用于稳定大豆油 - 水皮克林乳液,NaCl盐的使用量最少(20 mM)且纳米颗粒(NP)浓度低于1 wt%。就减少液滴生长和减少乳析而言,纳米共轭物比单独的CNC或ChNC能更好地稳定乳液。当带相反电荷的CNC和ChNC质量比为1:1时,它们相互中和,在pH 6且无盐的情况下导致显著絮凝。拉曼光谱为ChNCs和CNCs之间的静电相互作用提供了证据,并生成了图谱,表明存在微米级长度的ChNC束组装体,其间插入了主要由CNC组成的类似大小的区域。先前的测量结果与纳米颗粒膜上的接触角相结合,表明共轭物在质量比为1:1时优先暴露了CNCs和ChNCs的疏水结晶平面,这也是稳定大豆油 - 水皮克林乳液的最佳比例。