A study on the chemical composition of albino tea cultivars

Tea cultivars 'Xiaoxueya' and 'White leaf No. 1' have been bred from natural albino mutants of tea plants (Camellia sinensis) and have white tea shoots when the environmental temperature is below 20 degrees-22 degrees C in the early Spring. White tea shoots are used to produce high grades of unfermented tea in China because of their special leaf colour and flavour. The chemical compositions of their shoots were determined by high performance liquid chromatography and compared with 'Zhenong-113', a common tea cultivar used for green tea production. Eighteen amino acids and eight catechins were detected in the three cultivars examined, of which theanine was the most abundant amino acid, followed by arginine, glutamic acid, histidine, aspartic acid and threonine. The most abundant catechin was (-) epi-gallocatechin gallate (EGCg), followed by (-) epi-catechin gallate (ECg), and (-) epi-gallocatechin (EGC). Both albino cultivars had significantly higher total amino acid concentrations, but significantly lower concentrations of total catechins and caffeine than 'Zhenong-113'. The relative compositions of amino acids and catechins differed between both albino mutants and 'Zhenong-113'. Six out of the 18 amino acids occurred at higher levels in the mutants, four were at lower levels, six showed no difference, and the remaining two were not consistent. ECg and epicatechin (EC) showed significantly lower levels, but EGC showed higher levels in the mutants, and no differences were observed for EGCg, (-) gallocatechin gallate (GCg) and (-) catechin gallate (Cg), while (-) gallocatechin (GC) and (-) catechin (C) were not consistent.