本文以紫甘蓝蔬菜为原料，进行了pH、金属离子和各种食品添加剂等一系列稳定性分析，探索紫甘蓝色素的最佳存储和使用环境。研究表明，紫甘蓝色素对pH敏感，随着pH增大，色素保留率逐渐减小;不同金属离子对紫甘蓝色素的稳定性也有影响，Fe³⁺会破坏紫甘蓝色素的结构，降低稳定性，保留率仅为8.68%;而Ca²⁺能提高其稳定性。添加剂蔗糖也可提高其稳定性，其中20 g·L^-1的蔗糖水溶液可将保留率提升至119.48%;而食盐、苯甲酸钠和山梨酸钾均会降低其稳定性。

Two new viologen-polyoxometalate hybrid crystalline materials: (MV)₂[HPW₂^ⅤW₁₀^ⅥO₄₀] ·2H₂O (1) and (EV)₂[Mo₈O₂₆] (2) have been synthesized by using the cations of 1, 1'-dimethyl-4, 4'-bipyridinium dichloride (methyl viologen, MV) and 1, 1'-diethyl-4, 4'-bipyridinium dibromide (ethyl viologen, EV) as the electron acceptors, and the electron-rich polyoxometalate anions as the electron donors. The structures of compounds 1 and 2 have been determined by single-crystal X-ray crystallography. Hydrogen bond interactions exist between the cations and the anions in 1 and 2. Interestingly, 2 has a photochromic performance with a light response time within 1 min. The photochromic mechanism of compound 2 has been investigated by solid-state diffuse reflection, electron paramagnetic resonance and theoretical calculation. 1 and 2 show good catalytic performance in the photocatalytic degradation of several organic dyes (methylene blue, pararosaniline hydrochloride and rhodamine 6G).