Abstract
Polyphenolic compounds present in fresh tea leaves are related to health benefits, and they can be used as food items and vitamin supplements. However, during conventional tea processing that includes cutting, rolling, and drying, the extraction step is missing. Moreover, process conditions are harsh for example, to destroy the remaining enzymes and to reduce the moisture content in a leaf, a high temperature has to be applied (above 80 °C). Therefore, there is a need for an alternative process for the extraction of polyphenols under mild conditions. The Product-driven process synthesis methodology a well-defined structured approach for the conceptual design of an extraction process for polyphenols from fresh tea leaves was highlighted in this study. Starting with specification of the input (fresh tea leaves) and output (polyphenols), we subsequently defined fundamental tasks to convert our raw material into the desired product. Among the different mechanisms that could be used to perform the tasks, pulsed electric field is selected as non-invasive and non- thermal mechanism for opening the cell structure in the plant raw material. Next we need to define the operating window for the pulsed electric field unit. An experimental design is setup and executed (varying several setting of the Pulsed Electric Field unit such as electric field strength, number of pulses and pulse duration) and from the collected data, the analysis of variance is used to determine which variables are significant. Furthermore, the outcomes of the statistical analysis help in defining the best operating conditions that maximizes the extraction yield of the polyphenols. We found that the optimal pulsed electric field settings are: 1.1 kV/cm field strength, 0.0001 s pulse duration and number of pulses 50. With obtained optimum settings maximum value of 32.5 % of extraction yield was achieved. The next step in the product-driven process synthesis methodology is to translate all gathered information into suitable process design.
