A review of anthocyanin-pectin complexes: construction methods, physicochemical properties and bioactive functions

Anthocyanins are natural pigments with potent antioxidant, anti-inflammatory, and other bioactive properties. However, their application is limited by chemical instability and sensitivity to environmental stress. Anthocyanin derivatives, including glycosylated, acylated, and methylated forms as well as metal ion chelates, enhance stability and bioactivity, while complexes with proteins and polysaccharides provide additional protection against degradation in food systems. In recent years, the formation of anthocyanin-pectin complexes has emerged as an effective strategy to improve anthocyanin stability. This review focuses on the latest progress in the preparation, structural characterization, stability, and bioactive functions of anthocyanin-pectin complexes. Advanced modification techniques, including high-pressure homogenization (HPH), ultrasound treatment (US), enzymatic modification, and metal ion enrichment, can modulate pectin conformation and binding sites, thereby enhancing anthocyanin affinity and functional performance. Microscopic analyses reveal that these complexes adopt more compact and homogeneous particle structures, facilitating thermal, storage, and digestive stability. Spectroscopic (FTIR, UV-Vis, NMR) and thermodynamic (ITC) studies indicate that complex formation is spontaneous and exothermic, with hydrogen bonding, electrostatic interactions, and hydrophobic forces acting synergistically. Collectively, these factors improve the antioxidant activity of the complexes, as well as their hypoglycemic, antibacterial, and anti-inflammatory effects, while contributing to gut barrier protection and modulation of intestinal microbiota. With continued investigation into their structure and interaction mechanisms, anthocyanin-pectin complexes are expected to provide natural and efficient solutions for stability enhancement and health promotion in the food industry.