UV-C treatment enhances organic acids and GABA accumulation in tomato fruits during storage

Tomato fruits contain much organic acids and γ-aminobutyric acid (GABA) during ripening which are beneficial to human health. The effects of 4 kJ/m2 UV-C treatment on the contents of organic acids and GABA, and the expression of related genes in tomato fruits during storage at 13 °C were investigated. The results showed that UV-C treatment significantly increased the organic acids and total soluble protein contents, whereas decreased the free amino acids and glutamate contents. Besides, UV-C treatment enhanced GAD activity while reduced GABA-T activity, which resulted in accumulation of GABA. Moreover, the genes involved in the biosynthesis of organic acids and GABA were up-regulated, including CS, PEPC1, PEPC2, mMDH, cMDH, GAD1, GAD2, and GAD3, while GABA-T1 and GABA-T3 which involved in GABA degradation were obviously decreased by UV-C treatment. These results indicated that UV-C treatment might be an effective approach to accumulate organic acids and GABA during tomato fruits ripening.