The fermentation process in tea manufacture. 12. The origin of carbon dioxide

Abstract
The fine minces of tea leaf used by the authors were almost completely devoid of respiratory activity. CO2 evolution in such minces was not associated with activity of any of the enzymes concerned with carbohydrate break-down. Oxidation of substances in the mince other than polyphenols is not detectable, so that CO2 probably originates mainly from polyphenol oxidation. Under factory conditions fermenting leaf in Assam shows little or no respiratory activity. CO2 production in fermentation in the factory is also largely due to polyphenol oxidation, but there may be other subsidiary sources.