Exogenous GABA enhances phenolics and maintains antioxidant capacity of blueberries by modulating the GABA shunt

Blueberries are highly favored by consumers owing to their abundant nutritional components. In the present study, fresh blueberries were subjected to an exogenous spray application of 0.5 mmol/L GABA, aiming to investigate its effect on the levels of phenolic compounds throughout the storage period. The results showed that the 0.5 mmol/L GABA treatment was effective in maintaining desirable fruit quality, delayed spoilage, and simultaneously inducing a significant increase in the concentration of certain phenolic substances, notably anthocyanins. Additionally, GABA enhanced the activities of enzymes associated with phenylpropanoid metabolism, antioxidant systems, and anthocyanin biosynthesis. The corresponding genes exhibited upregulated expression. Collectively, exogenous GABA application elevates the GABA content and antioxidant capacity of blueberries through the activation of phenylpropanoid metabolism and anthocyanin biosynthesis pathways.