Complexation of Anthocyanin‐Rich Blackberry Extract With Ozonated Sodium Alginate: Structural, Rheological, and Color Insights

Anthocyanins, valued for their health-promoting properties and their role as natural pigments, are highly susceptible to degradation, highlighting the need for strategies to improve their stability. Biopolymer-based systems are an alternative for interacting with and safeguarding these bioactive compounds. Ozonated alginate is a potential candidate for complexing with anthocyanins because of its modified structure and properties. This study aimed to evaluate the complexation of anthocyanin-rich blackberry extract with ozonated sodium alginate (SA) solutions and to compare its properties to those of native (i.e., extracted from seaweed in the lab) and commercial SA. Rheological analyses revealed shear-thinning behavior in the SA and anthocyanin-rich extract composite solutions, indicative of their incorporation and molecular entanglement. Structural analyses provided insights into the electrostatic interaction between the biopolymer and the extract, with new peaks and chemical shifts appearing. Microscopy revealed a porous network, suggesting the formation of complexes between SA and the anthocyanin-rich extract composite solutions. Additionally, the SA and anthocyanin-rich extract solutions exhibited an attractive color. In conclusion, the complex comprising ozonated SA and anthocyanin-rich extract has potential applications in diverse sectors, particularly in the food and medical industries, because it leverages the low molecular weight of SA and the bioactive properties of anthocyanins.