Black Tea Research Paper

Optimization of total phenolics content and total antioxidant activity of black tea using response surface methodology

Tah Clovis Tiku1, Feumba Dibanda Romelle2, Yadang Germaine2, Nyobe Emillienne Carine2, Achegui Nestor2, Medoua Nama Gabriel, Mbofung Carl Moses1

1College of Technology, University of Bamenda, Cameroon

2Food and Nutrition Research Centre, Institute of Medical Research and Medicinal Plants Studies, Cameroon

Abstract

Response surface methodology was used to optimize the fermentation conditions for the total phenolics content and antioxidant activity of black tea (Camellia sinensis). Fresh tea leaves were fermented following a rotatable central composite design of eleven experiments replicated thrice. The minimum and maximum fermentation time and temperature were respectively of 1

To visualize the effects of fermentation temperature and time and the relationships between the factors and the response variables, 2D contour plots of the fitted regression equations were generated. Figure 1 shows the contour plots of fermentation time and temperature on total phenolics content (a) and total antioxidant activity (b) of black tea. It is noticeable from figure 1a that when fermentation was conducted for 0.5 to 1 h, total phenolics content increased with fermentation temperature between 28 and 38 °C. After 38 °C, total phenolics content started to decrease. When fermentation was conducted for more than 1 h, total phenolics content decreased with fermentation temperature below 38 °C and increased with fermentation temperature beyond 38 °C. A similar trend was observed in case of total antioxidant activity (figure 1b). Concomitant results were found by [13] who reported temperatures between 30 - 38°C to significantly improve polyphenol contents of bush tea fermented for 30