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Stimulated biosynthesis of delphinidin‐related anthocyanins in tea shoots reducing the quality of green tea in summer
Author(s) -
Zhang Qunfeng,
Hu Jianhui,
Liu Meiya,
Shi Yuanzhi,
De Vos Ric C. H.,
Ruan Jianyun
Publication year - 2019
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.10158
Subject(s) - delphinidin , anthocyanin , shoot , camellia sinensis , catechin , food science , proanthocyanidin , chemistry , fructose , kaempferol , glycoside , flavonoid , botany , biology , biochemistry , polyphenol , cyanidin , antioxidant
Abstract BACKGROUND Greater proportions of purple tea buds and leaves usually appear in the summer, which seriously affects the color and taste quality of green tea products, yet the metabolism of purple tea shoots in summer remains unclear. Here, the metabolomic profiles and gene expression of related flavonoid metabolic pathways in the purple and normal green shoots of ‘Longjing 43’, and the quality of green tea made with these two phenotypes, were analyzed and compared. RESULTS Differential metabolites identified using high‐performance liquid chromatography–Orbitrap/mass spectrometry indicated that anthocyanin biosynthesis in purple leaves was enriched, with higher levels of anthocyanidins (delphinidin‐hexose‐coumaroyl showed the greatest increase), proanthocyanidins (oligomers of catechins) and kaempferol glycoside. Expression patterns of the genes ANR , ANS , FLS , LAR , C4H , PAL , CHI , CHS and DFR revealed that the metabolism of anthocyanin is positively regulated by high temperature and/or light levels in summer. Gas chromatography–mass spectrometry results showed that, in purple tea shoots, the metabolism of carbohydrates was enriched whereas that of amino acids was diminished, while their mannose, fructose, d ‐galactose, sorbose and d ‐glucose contents were more than double those found in green leaves. A sensory evaluation confirmed that a greater quantity of purple shoots had a greater negative impact on green tea quality because of a bitter taste and dark color (leaves and infusions were tested). CONCLUSIONS These results highlight the need for and possibility of improving commercial tea quality via cultivation that controls the temperature or light of tea gardens during the summer. © 2019 Society of Chemical Industry