Umami

Glutamate, being an amino acid, is naturally present in green tea. L-theanine, another amino acid, intensifies the umami taste besides adding sweetness to tea. Therefore, teas with high L-theanine content are rich in umami taste, such as gyokuro or high-grade sencha. Bancha and houjicha have very little L-theanine and glutamate content, so you won’t find much umami taste there. (Source: Umami Info Centre)