Akademik Veri Yönetim Sistemi
Microchemical Journal, cilt.225, 2026 (SCI-Expanded, Scopus)
The reliable evaluation of total antioxidant capacity (TAC) is essential for assessing the nutritional and functional properties of foods. In this work, a biodegradable colorimetric sensor was developed by combining κ-carrageenan and alginate hydrogels cross-linked with CaCl₂ and functionalized with the CUPric ion Reducing Antioxidant Capacity (CUPRAC) reagent. The hydrogel matrix provided a stable three-dimensional support for reagent immobilization, supported by the electrostatic interaction of alginate-COO− and carrageenan-SO3− with the cationic Cu(II)-Nc chelate, as confirmed by FTIR, TGA, SEM, XPS, and XRD analyses. The proposed sensor exhibited excellent linearity with Trolox (TR) calibration (R2 > 0.99), and recovery experiments in spiked black tea infusions yielded satisfactory values between 76% and 83%. The LOD and LOQ values for TR were found to be as 8.42 μM and 28.05 μM, respectively. Selectivity tests demonstrated that the presence of common ions and sugars at 1000-fold excess concentrations did not interfere with the analytical response. Comparative measurements of tea infusions, fruit juices, and cereal extracts showed that the ranking of TAC values obtained with the hydrogel sensor was consistent with that of the conventional spectrophotometric CUPRAC method, while compound-specific differences reflected structural and matrix-dependent interactions. The use of biodegradable polysaccharides not only ensures environmental compatibility but also facilitates low-cost, portable, and smartphone-assisted readouts. These results indicate that the proposed hydrogel-based CUPRAC platform represents a promising tool for rapid, reliable, and sustainable TAC determination in diverse food matrices.