Preharvest Multiple Applications of GABA Improve Quality Traits and Antioxidant Compounds of Pomegranate Fruit during Storage

Abstract

GABA (γ-Aminobutyric acid) is an amino acid with diverse effects on plant development, including delayed senescence in horticultural commodities. The main goal of this research was to investigate the impact of GABA applications to pomegranate trees on the ‘Mollar de Elche’ quality traits and antioxidant compounds during storage for 60 days at 10 °C. In the 2019 experiment, pomegranate trees received foliar sprays of GABA at 10-, 50- or 100-mM concentrations at three stages of fruit development. Pomegranates harvested from GABA-treated trees exhibited enhanced fruit firmness, titratable acidity, the red color of skin and aril, and higher levels of total phenolics and total and specific anthocyanins compared to those obtained from the control group. These quality traits were maintained at higher levels during 60 days of preservation at 10 °C, and the most important effects were observed for 100 mM dose. In a 2020 experiment, GABA was sprayed at a 100 mM dose, and results were confirmed, showing a retard of the ripening process in pomegranates from GABA-treated trees concerning controls for two months of storage and an extension of their shelf life (with optimal quality traits appreciated by consumers) from 30 to 60 days. Moreover, the increase in anthocyanin content due to GABA treatments resulted in redder fruits, which would appeal more to consumers and have improved health benefits.