Changes in the ethanol‐insoluble material of tea leaves (Camellia sinensis L.) during maturation

The ethanol‐insoluble material (e.i.m.) of immature and mature tea leaves was fractionated into hot‐water‐soluble polysaccharides and proteins, ammonium oxalate‐soluble pectic acid, hemicelluloses A and B and α‐cellulose, by successive extraction with hot water, ammonium oxalate, sodium hypochlorite and cold alkali. The final residue was termed α‐cellulose. The hot‐water extract and the hot‐water‐insoluble residue were found to contain appreciable quantities of protein nitrogen. Each fraction was hydrolysed and the mixture of sugars was separated on paper chromatograms and estimated. It appeared that each stage of the extraction procedure removed from the e.i.m. a complex mixture of polysaccharides. The sugars produced on hydrolysis of the arbitrary fractions from immature and mature leaves were qualitatively similar, although there were quantitative differences and were glucose, galactose, xylose, arabinose, rhamnose, galacturonic acid and an unidentified uronic acid. Maturation was mainly accompanied by an increase in the content of lignin, hemicelluloses and α‐cellulose.