Synergistic Effect of Foliar L-α-Amino Acid and Sorbitol Application on Secondary Metabolism and Physiological Resilience of Pomegranate cv ‘Mollar de Elche’

‘Mollar de Elche’ pomegranate is highly valued for its sweet flavor but faces significant commercial hurdles due to pale coloration and sensitivity to postharvest disorders. This study investigates the impact of preharvest foliar applications of L-α-amino acids, applied alone (AA) or combined with 2.5% sorbitol (Sor–AA), on secondary metabolism and physiological resilience, defined here as the fruit’s capacity to maintain metabolic homeostasis and stabilize antioxidant pigments during cold storage (7ºC). Our results show that both treatments triggered a substantial shift in secondary metabolism, doubling anthocyanin concentrations at harvest and effectively overcoming the cultivar’s color deficit. While the AA treatment maximized fruit quantity per tree, the Sor–AA combination achieved the highest total yield (83.58 ± 6.82 kg) and individual fruit weight (469.00 ± 16.00 g) through a ‘metabolic bypass’ that optimizes energy use. Crucially, the physiological resilience of the fruit was uniquely bolstered by the Sor–AA treatment, which was the only strategy to stabilize anthocyanin levels (~108 mg L−1) and maximize free ellagic acid in the husk (371.72 mg kg−1) throughout 42 days of storage. Multivariate PCA (explaining 79.79% of variance) confirmed that the synergy of amino acids and sorbitol triggers systemic metabolic reprogramming. Consequently, this targeted agronomic approach could provide significant economic benefits by increasing the proportion of export-grade fruit and extending the commercial window for the pomegranate sector.