Brewing Conditions Optimization of <i>Berberis vulgaris</i> L. Tea by Assessing Antioxidant Activity and Phenolic Content Using Box-Behnken Design

Berberis vulgaris is a wild fruit with valuable antioxidant and phenolic content but limited dietary use. This study aimed to optimize the brewing conditions of instant B. vulgaris tea to maximize its antioxidant activity and Total Phenolic Content (TPC). A Box-Behnken design was employed to evaluate the effects of brewing temperature (60-90 °C), time (5-15 minutes), and liquid-to-solid ratio (1-3 g/mL) on tea quality. 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity and TPC were measured as response variables. Results showed that the liquid-to-solid ratio significantly affected DPPH, while temperature had the most influence on TPC. Optimization using response surface methodology identified ideal conditions as 90 °C, 13.69 minutes, and a 1 g/mL ratio. Under these conditions, DPPH and TPC values were significantly higher than those reported in previous studies. The findings demonstrate that B. vulgaris tea, when properly brewed, can serve as a potent source of natural antioxidants. This study provides a scientific basis for promoting the nutritional use of wild fruits and supports further product development using B. vulgaris.