Dynamic change of oligopeptides and free amino acids composition in five types of tea with different fermentation degree processed from the same batch of fresh tea (Camelilia Sinensis. L.) leaves

Our previous studies have confirmed oligopeptides could be meaningful to tea taste and biofunction. As the total content of oligopeptide among different tea types were varied. It is a natural speculation that certain tea processing step could be vital for oligopeptides enrichment. In current study, five types of traditional Chinese tea were produced from the same batch of fresh leaves. Step processing samples were acquired through which to profile the oligopeptides and free amio acids composition change during tea processed. As a result, firstly, withering was the vital step for oligopeptide enrichment, followed by fermentation, yellowing and drying. Secondly, as the enrichment of oligopeptides was often accompanied by the increase of protein amino acids, suggesting certain proteins degradation in fresh leaves could be the main source of oligopeptides. Thirdly, a total of 166 abundant oligopeptides were screened out, through which 14 high degradation protein were also located by protomic approaching.