Abstract: This study systematically evaluated the effects of high-fructose corn syrup (HFCS) and its major degradation products, furfural (Ff) and 5-hydroxymethylfurfural (5-HMF), on the color and stability of cyanidin-3-glucoside (C3G). The reaction products between HFCS degradation products and C3G were determined by ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), and quantum chemical analysis was performed to evaluate their reactivity and predict reaction sites. Based on this, the mechanism by which HFCS degradation products affect anthocyanin stability was elucidated. The results showed that HFCS accelerated C3G degradation and color deterioration in a concentration-dependent manner. After 21 days of dark storage at pH 3.0–4.0, HFCS reduced the retention rate of C3G and concentration-dependently increased the ΔE value of the solution. Elevated temperature and light exposure further decreased C3G stability. The formation of Ff and 5-HMF increased with temperature, and Ff exhibited a greater promoting effect on C3G degradation than 5-HMF. UPLC-MS/MS analysis and quantum chemical calculation confirmed the formation of C3G-Ff/5-HMF adducts. The C6 and C8 positions of C3G exhibited high nucleophilic reactivity, whereas the carbonyl carbons of Ff and 5-HMF acted as major electrophilic sites. Compared with 5-HMF, Ff exhibited higher electrophilicity, contributing to its stronger promoting effect on C3G degradation. These findings demonstrate that HFCS degradation products accelerate C3G degradation through electrophilic addition with its nucleophilic sites, providing a theoretical basis for controlling anthocyanin stability in sugar-containing food systems.

Key words: anthocyanins; stability; high-fructose corn syrup; furfural; 5-hydroxymethylfurfural