Effects of Particles Size on Tea Processing: A Perspective on Zobo Production

This report presents a comprehensive review of the effects of tea particle size (PS), dipping temperature, infusion time, dipping frequency, and effect of permeance on tea infusion focusing on zobo (Roselle – Hibiscus sabdariffa) tea. Tea production process follows a series of unit operations depending on the type of tea being produced. Various forms of tea are scented, white, oolong, green, and black teas. Generally, the basic unit operation involves include withering, maceration, fermentation, fixation, rolling or shaping, drying, and curing or aging of the tea leaves. Before drinking, the processed tea is prepared by infusing the tea leaves in hot or cold water with or without tea bags. For maximum extraction of bioactive compounds which are responsible for the high nutritive and functional properties of tea, it is important to understand tea infusion process and factors affecting the infusion kinetics (IK). PS and distribution of food powders, their measurements, and their instrumentations are displayed as well as the undesirable phenomena in food powders. Tea packages and tea bag selections, the effect of different factors in tea IK, novel technology for tea production, and future prospects of tea production are also discussed. This review aims at providing information for the understanding of tea PS and factors affecting tea IK thereby enhancing the understanding of different principles behind tea infusion; a perspective on zobo production.