Dynamic changes in amino acids, catechins, caffeine and gallic acid in green tea during withering

•Most individual amino acids increased with increasing withering time and temperature.•Theanine (Thea) contents slightly decreased with fluctuations during withering.•Aspartic acid contents increased at the beginning but decreased afterward.•Most catechins decreased with increasing withering time and temperature.•Caffeine contents increased with increasing withering time.