Product-driven process synthesis: Extraction of polyphenols from tea

In this contribution, the Product-Driven Process Synthesis methodology is used as a well-defined structured approach for the conceptual design of an extraction process for polyphenols from fresh tea leaves. A detailed specification of the starting material (fresh tea leaves) and product (polyphenols) leads to a subsequent definition of fundamental tasks to convert our raw material into the desired product. Among the different mechanisms and techniques that could be used to perform the tasks under mild conditions, pulsed electric field has been selected as non-invasive and non-thermal method for cell wall disruption. To define the operating window for pulsed electric field method an experimental design has been defined and executed (varying several settings of the pulsed electric field). From the collected data, the analysis of variance has been used to determine which variables are significant i.e. electric field strength, pulse duration and number of pulses. Box-Behnken design has been used as part of statistical analysis to find optimal pulsed electric field settings to maximize the extraction yield of polyphenols (extraction yield). With the outcome of optimization of pulsed electric field settings maximum value of 32% of extraction yield was achieved. This is better as compared to a conventional process where extraction is done by hot (boiling) water or solvents while not destroying valuable components in raw material itself.