Chinese researchers, from the Huazhong Agricultural University, proved that y-aminobutyric acid (GABA) plays a key role in citrate metabolism.
"We studied the effects of exogenous GABA treatments on citrate metabolism and on the post-harvest quality of fruit stored. After the treatment, citrate content increased significantly, probably mostly due to an inhibited expression of glutamate decarboxylase. Amino acids, including glutamate, alanine, serine, aspartate and proline, also increased."
The GABA treatment also decreased fruit rot rate and affected enzyme activity.
"Results show that GABA treatment is an effective approach to maintaining the post-harvest quality and improving the storing performances of citrus fruit."
Source: Sheng Ling, Shen Dandan, Luo Yi, Sun Xiaohua, Wang Jinqiu, Luo Tao, Zeng Yunliu, Xu Juan, Deng Xiuxin, Cheng Yunjiang, 'Exogenous γ-aminobutyric acid treatment affects citrate and amino acid accumulation to improve fruit quality and storage performance of postharvest citrus fruit', 2017, Food Chemistry, Vol. 216, pag. 138-145. www.sciencedirect.com/science/article/pii/S0308814616312547