The effect of different wall materials on the physicochemical properties and antioxidant activity of pomegranate peel polyphenols (PPP) microcapsules

Pomegranate peel polyphenols (PPP) are natural compounds known for their various biological activities; however, they are easily degraded by environmental conditions, leading to a reduction in their biological activity and health benefits. Therefore, improving the stability of PPP is a critical question that needs to be addressed. This study aimed to evaluate the efficacy of five common microcapsule wall materials-carboxymethyl cellulose sodium (CMCNa), sodium alginate (SA), gum Arabic (GA), beta-cyclodextrin (β-CD), and hydroxypropyl starch (HPS)-in encapsulating PPP to enhance its stability and antioxidant activity. Remarkable results indicated that β-CD-PPP exhibited the lowest moisture content (3.68 %), the highest thermal decomposition temperature (306.03 °C), and the strongest antioxidant activity (IC₅₀ = 0.26 mg/mL for DPPH, 96.57 % for ABTS). In contrast, CMC-Na-PPP demonstrated the highest encapsulation efficiency (97.94 %) and the largest particle size (9895.63 nm). Moreover, the molecular docking results revealed that all wall materials formed intermolecular interactions with PPP components, with notable differences in binding energies; CMC-Na-PPP had the highest binding energy at -4.38 kcal/mol. These variations are attributed to factors such as molecular weight, free active groups, and spatial conformation of the wall materials. Therefore, in order to fully utilize the biological activity of PPP in food processing, microcapsules formed with β-CD as the wall material are more valuable compared to those formed with other wall materials.