Interactive Effects of Growing Environment and Fermentation on Polyphenol Content, Antioxidant Activity, and Sensory Acceptance of Black Tea

Abstract

Polyphenols are major bioactive compounds responsible for the antioxidant properties of tea. This study evaluated the interactive effects of tea-growing location and fermentation duration on polyphenol content, antioxidant activity, and sensory acceptance of black tea produced in East Java, Indonesia. A factorial completely randomized design was applied using two growing locations (Wonosari, Malang, and Sirah Kencong, Blitar) and four fermentation durations (0, 60, 90, and 120 min), with three replications. Total polyphenol content, antioxidant activity determined by the DPPH radical scavenging assay, and sensory acceptance of appearance, color, aroma, and taste were analyzed. The interaction between growing location and fermentation duration significantly affected (p < 0.05) polyphenol content, antioxidant activity, and sensory acceptance. The highest values were obtained from tea leaves grown in Wonosari and fermented for 120 min, resulting in a total polyphenol content of 7.25 mg GAE g⁻¹ and antioxidant activity of 91.42%, together with the highest consumer acceptance scores. Under the same fermentation duration, black tea from Sirah Kencong exhibited lower polyphenol content (6.64 mg GAE g⁻¹) and antioxidant activity (80.48%). These findings demonstrate that both growing environment and fermentation duration are important factors influencing the chemical and sensory characteristics of black tea, with tea from Wonosari fermented for 120 min exhibiting the most desirable quality attributes