Optimization of fermentation of himalayan black tea beverage using response surface methodology

The present study was planned to enhance the physicochemical properties of Himalayan black tea through optimized fermentation, utilizing Response Surface Methodology (RSM). The study utilized Response Surface Methodology (RSM) in conjunction with a Box–Behnken Design (BBD) to examine the interplay between three independent variables: temperature (27–29°C), sugar concentration (90–110 g/L), and fermentation period (13–15 days) on two crucial responses: pH and titratable acidity. The model's high R 2 values and lack of fit indicated that it was statistically significant, proving that the design was appropriate for process optimization. The optimal condition, out of the three software-generated optimum points, was found to be 13.51 days at 27.52°C with 101.0 g/L sugar, yielding a pH of 3.44 and titratable acidity of 14.19 g/L. All optimized runs achieved a perfect desirability value of 1.000, indicating high model accuracy and reproducibility. This research proposes a novel research method to optimize the fermentation parameters of Himalayan black tea using Response Surface Methodology, revealing its potential as a biofunctional base for kombucha. The optimized conditions provide a scalable foundation for future applications in health-promoting fermented beverages and functional food industries. The model's robustness was statistically validated through analysis of Variance (ANOVA), confirming its strong influence on all investigated parameters (p < 0.001). These findings demonstrate that by precisely adjusting fermentation parameters, the quality of Himalayan black tea can be significantly improved, offering consumers a more potent and beneficial product. • RSM was employed to optimize Himalayan black tea fermentation parameters. • Optimal: 13.5 d, 27.5 °C, 101 g/L sugar; resulted in pH 3.44 and 14.19 g/L acidity. • ANOVA confirmed statistical reliability and reproducibility of the developed model. • Optimization improved physicochemical traits of Himalayan fermented tea beverage. • Findings support science-based formulation of functional tea beverages.