Core Insights - The research conducted by a team from Anhui Agricultural University reveals that the loss of freshness in tea is linked to a specific component called theanine, which has a flavor profile similar to monosodium glutamate [2][5][12]. Group 1: Theanine and Tea Freshness - Theanine is the most abundant free amino acid in tea, comprising 1% to 2% of the dry weight of early spring tea, contributing to its fresh taste [6][10]. - The content of theanine significantly decreases after the Qingming Festival as temperatures rise, sometimes dropping by more than half, which negatively impacts the flavor of later teas [12][13]. Group 2: Mechanism of Theanine Degradation - The research identifies the complete process of theanine degradation, highlighting the roles of mitochondrial carrier protein CsTHS1 and theanine hydrolase CsGGT2 [14][18]. - CsTHS1 acts as a "courier," transporting theanine from the cytoplasm to the mitochondria, while CsGGT2 functions as a "decomposer," breaking down theanine, with both proteins' activity increasing with temperature [16][20]. Group 3: Implications for Tea Cultivation - The findings provide new insights for flavor improvement in other crops, suggesting the potential for precision breeding through gene editing, specialized fertilizers to maintain theanine levels, or shading techniques for smart cultivation to enhance spring tea quality [22][24].