Catechin stability in powder and solution systems

Na Li, Purdue University


Tea is one of the most commonly consumed beverages in the world. Green tea catechins have been associated with a variety of health benefits, attracting increasing attention worldwide. Thus, the uses of green tea powder, concentrates, solutions, and purified green tea extracts in tea beverages, functional foods, and dietary supplements in the food and pharmaceutical industries are increasing. However, a primary concern of catechins is their instability during manufacturing and storage. Therefore, understanding catechin stability is essential to ensure the quality and delivery of these bioactive components in food systems. In this study, catechin stability in spray-dried green tea powders, concentrated solutions, and dilute solutions , as well as EGCG powder crystalline and amorphous solids were investigated across a range of storage (including temperature, relative humidity (RH)) and/or formulation (concentration, pH, physical state of the solid matrix) conditions. The stability of catechins was found to decrease with increasing amounts of water present in both solid and solution states. The chemical stability of catechins in green tea was dependent on temperature, RH, pH, the physical state of the food matrices in solid state, and concentration in solution state. Kinetic models were developed for individual catechins in green tea. The physical stability of amorphous EGCG powder was sensitive to environmental RH and temperature, while its chemical stability was affected by RH, temperature, and the crystallinity of EGCG. In solutions, epimerization and cleavage reactions were found to be the major reactions causing chemical degradation. In solid states, epimerization was suppressed as environmental RH increased, while oxidation with the formation of theasinensin and a colored compound became predominant. These studies provided shelf-life models for catechins in the solid state, and furthered the understanding of mechanisms of catechin degradation in green tea powders and purified EGCG in both solution and solid state.




Mauer, Purdue University.

Subject Area

Food Science

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