Designing Antioxidant-Enriched Extracts from Erica carnea L.: Optimization, Kinetics, and Thermodynamic Insights

Erica carnea L. has recently gained attention as a promising natural source of antioxidants suitable for food and beverage applications. This study aimed to obtain an antioxidant-enriched extract by optimizing the key extraction variables. A full factorial design was used to evaluate the effects of ethanol concentration, extraction time, and temperature, followed by validation through multiple antioxidant assays, including DPPH, ABTS, hydroxyl radical scavenging, lipid peroxidation inhibition, and metal chelation. The most efficient extraction was achieved at 30% ethanol, 120 min, and 50 °C, yielding IC₅₀ values of 18.42 μg/mL (LP), 15.04 μg/mL (DPPH), 5.14 μg/mL (MC), 11.28 μg/mL (OH), and 10.06 μg/mL (ABTS), in agreement with the model predictions. Extraction kinetics were described using an unsteady-state diffusion model, supported by low root mean square (RMS) values and high coefficients of determination. Thermodynamic analysis indicated an irreversible, endothermic process, highlighting the energetic requirements for phenolic release from plant tissue. The combined statistical and kinetic approach provides a clearer understanding of how process variables influence antioxidant recovery. In addition to strong antioxidant activity, the optimized extract showed measurable cytotoxic and antibacterial effects. Overall, these findings highlight E. carnea as a valuable material for developing antioxidant-rich formulations, with extraction efficiency governed by predictable kinetic and thermodynamic behavior.