Characterization and evaluation of tea bag papers.

The infusion kinetics of tea bags containing black tea or green tea has been studied in detail in the past. However, the tea bag papers have never been characterized and evaluated earlier to understand their contribution towards tea bag infusion. In the present work, papers used for making tea bags were characterized for thickness, wettability, surface topography, pore size, porosity and permeance to understand their influence on infusion kinetics of tea bags. Scanning electron microscopy studies highlighted the pore structure and porous nature of tea bag papers. The porosity of tea bag paper was quantified using image processing and permeance was determined experimentally. Besides, a relationship between porosity and permeance of tea bag papers has been perceived. A general trend of increase in permeance with increasing porosity was observed. Woven nylon paper showed the highest permeance (23.9 × 10 m/s) when compared with other tea bag papers. Furthermore, an initial infusion rate was determined using initial infusion data of tea bag infusion for different tea bag papers. The influence of permeance on the initial infusion rate of tea bag papers has also been investigated.