Vol. 8, Issue 6 (2019)

Author(s):
Sahijul Islam, Manashi Das Purkayastha, Sewali Saikia and Shantanu Tamuly

Abstract:
Central composite design (CCD) under response surface methodology (RSM) was used to optimize the process conditions for enhancing the yield of total polyphenols (TP) from fresh tea leaves and its antioxidant activity (AA). The independent variables were leaves-to-solvent ratio (LTSR) (1:20-40 w/v), extraction time (1-3 h), and number of extractions (1-3 times). The solvent used for extraction was a mixture of methanol and acetone (1:1 v/v), as it gave the maximum TP and AA among other tested solvents (water, methanol, ethanol and acetone). The optimum condition of process variables was found to be LTSR 30.4 mL, extraction time 1.5 h, and number of extraction as 1. Under the predicted condition, the TP and AA were obtained as 4.93 g catechol equivalent (CE) per 100 g of tea leaves and 87.74%, respectively. The predicted and experimental values were found to be in congruent with each other, which showed the validity of the developed models.