As an opaque and complex colloidal mixture, milk is usually present as a positively charged colloid under acidic conditions. Adding negatively charged colloids can lead to protein aggregation in milk. Alpha-lactalbumin (α-La) is an essential component of whey protein and has good physicochemical properties for functional food development. We combined spectroscopy, computer simulations, and other techniques to comparative analyze the mechanisms and characteristics of isolated α-La aggregation induced by CI Acid Red 27 (C27)/CI Acid Red 14 (FB) containing different sulfonyl groups in vitro. The results showed that C27/FB (5.25 × 10⁻⁵ mol·L⁻¹ to 3.15 × 10⁻⁴ mol·L⁻¹) induced the formation of fibril-like aggregates under acidic conditions (pH 2.0 and 4.0) mainly benefit from hydrophobic and electrostatic forces. Weakening and redshift of α-La's characteristics negative peak were observed (208 nm to 218 nm) on circular dichroism. β-Crosslinks self-assembly and reorganization of disulfide bonds occurred during protein fibrillation. Moreover, the different redshift intensity of Congo red binding to amyloid fibrils was observed to be induced by C27 (>551 nm) and FB (>536 nm), and the direct observation by TEM demonstrated the ability to induce protein fibrillation is C27 > FB. Edible azo dyes with more sulfonyl groups would possess a stronger ability to induce protein fibrillation.

作为一种不透明且复杂的胶体混合物，牛奶在酸性条件下通常以带正电的胶体形式存在。添加带负电的胶体会导致牛奶中的蛋白质聚集。α-乳清蛋白（α -La）是乳清蛋白的重要组成部分，对于功能性食品开发具有良好的理化特性。我们结合光谱学、计算机模拟等技术，对比分析了含有不同磺酰基的CI酸性红27（C27）/CI酸性红14（FB）在体外诱导分离α -La聚集的机制和特征。结果表明，C27/FB（5.25 × 10 ^-5  mol·L ^-1至3.15 × 10 ^-4  mol·L ^-1）在酸性条件（pH 2.0和4.0）下诱导原纤维状聚集体的形成主要受益于疏水力和静电力。圆二色性观察到α -La特征负峰（208 nm至218 nm）减弱和红移。蛋白质原纤维化过程中发生β-交联自组装和二硫键重组。此外，观察到C27（>551 nm）和FB（>536 nm）诱导刚果红与淀粉样原纤维结合的不同红移强度，并且通过TEM直接观察表明诱导蛋白原纤维的能力是C27>FB 。磺酰基越多的食用偶氮染料诱导蛋白质原纤维化的能力越强。