Effect of soybean protein isolate-Aronia melanocarpa extract interaction on the bioaccessibility of anthocyanins after low-pressure cold plasma treatment

This study evaluated the impact of cold plasma (CP) treatment on the structural and digestive properties of soybean protein isolate (SPI)– Aronia melanocarpa extract (AME) complexes. CP treatment significantly modified the secondary structure of SPI–AME complexes, while AME addition enhanced protein stability by increasing α-helix content. FTIR and UHPLC-PDA analyses suggested pronounced structural transformations and substantial phenolic changes, particularly for chlorogenic acids and cyanidin derivatives, throughout the digestive process. Anthocyanin levels increased in the gastric phase due to flavylium cation stabilization but declined significantly at intestinal pH 7.0. CP-treated complexes preserved anthocyanin bioaccessibility (0.84–0.89-fold) compared to free AME, which showed a sharp decline (0.02-fold). Molecular docking further supported these findings, revealing that cyanidin derivatives exhibited strong binding affinities with glycinin (1FXZ), explaining the enhanced complex stability. These results indicate that CP-mediated protein-polyphenol interactions successfully protect sensitive bioactives during digestion, offering an approach for developing stable functional food systems. This figure was prepared using Freepik, Powerpoint and ChemSketch applications. • Soybean protein isolate (SPI)– Aronia melanocarpa Extract (AME) interaction presents a promising system for the development of functional foods. • Cold plasma (CP) application alters the structure of protein–anthocyanin interactions and improves digestibility. • Increased protein concentration significantly alters the stability of anthocyanin–protein complexes.