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

Abstract

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 a-cellulose, by successive extraction with hot water, ammonium oxalate, sodium hypochlorite and cold alkali. The final residue was termed a-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 a-cellulose.

The isolation and analysis of cell wall material from the alcohol‐insoluble residue of cabbage (Brassica oleracea var. capitata)

“…To obtain a clearer indication of the types of polymers constituting the cell wall complex the CWM was fractionated with hot water, hot ammonium oxalate, 1~ KOH and 4~ KOH to leave a residue of acellulose. 18 The yields of the fractions obtained and the sugar composition after hydrolysis are presented in Table 5. In the hot water-soluble fraction the large amount of arabinose with relatively low levels of other neutral sugars pointed to the presence of an arabinan.…”