The Use of Anaerobic Conditions and Plasma Environment During Tea Processing to Enhance Polyphenols in Made Teas

Abstract

Tea prepared from leaves of Camellia sinensis is the most consumed beverage in the world, second only to water. Health benefits associated with tea consumption include reduced risk of cancer, type 2-diabetes, cardiovascular diseases, obesity and inflammation. Polyphenols in tea are responsible for observed activity and their content is reduced during the fermentation process of making tea. Green tea is unfermented and thus has high content of polyphenols, whereas black tea is fully fermented. Use of tea processing techniques that preserve or enhance the content of beneficial polyphenols will provide teas that can be used to mitigate against the aforementioned diseases. This study sought to review tea processing techniques that utilise plasma and anaerobic environment to produce made teas with high content of beneficial polyphenols. Literature review was carried out in PubMed, Science direct and google scholar to obtain peer reviewed papers on tea processed under anaerobic conditions and plasma environment. Previous studies reported that tea processed anaerobically using nitrogen gas had high contents of ˂-aminobutyric acid (GABA), a hypotensive compound, and alanine. GABA tea is also rich in polyphenols. that withering tea anaerobically in nitrogen gas with or without plasma environment produced green tea having high content of polyphenols compared to purple, black and Oolong tea and that pickled tea produced by anaerobic solid-state fermentation has high contents of gallic acid (25.7g/kg) and free amino acids beneficial to human health. Thus tea processed anaerobically using nitrogen gas and plasma environment is rich in GABA, and polyphenols beneficial to human health. This can be one way of producing value added tea in the Kenyan market. Further studies are being undertaken to evaluate the anticancer properties of Kenyan polyphenol enriched teas.