PERTANIKA JOURNAL OF TROPICAL AGRICULTURAL SCIENCE

γ-Aminobutyric acid (GABA) is a functional metabolite associated with tea quality and potential health benefits, and it is known to accumulate in plants under abiotic stress conditions. However, information regarding the physiological response and GABA accumulation in harvested tea shoots during post-harvest handling remains limited. Therefore, this study evaluates the effects of several post-harvest environmental conditions, including water status, temperature, light availability, and treatment duration, on GABA accumulation and the physiological response of harvested tea shoots under controlled conditions. The research was conducted in 2022 using tea shoots of the TTRI-12 cultivar consisting of one bud and three leaves. The shoots were harvested from the experimental garden of National Chung Hsing University and arranged in a completely randomised design with three replicates. The results showed that various post-harvest stress treatments significantly affected GABA content, proline levels, water content, and stomatal conductance. An overall increase in GABA content was observed in treatments involving soaking, high temperature (37.5°C), dark conditions, and a 2-hour treatment. Pearson correlation analysis indicated that proline was the only physiological parameter significantly associated with GABA accumulation. These findings suggest that harvested tea shoots maintain physiological activity and metabolic activity during the post-harvest period. Overall, manipulating post-harvest environmental conditions has the potential to support the development of GABA tea and improve its quality.