Chilling Tolerance of Basil Is Not Affected by Ultraviolet-B/C Light: A 1H NMR Study

Basil ( Ocimum basilicum L.) is a popular culinary herb, but its sensitivity to low temperature limits its compatibility with other crops during postharvest transport and storage. Adjusting cultivation lighting may increase the antioxidants and sugar status, potentially improving cold tolerance. Ultraviolet (UV) light is thought to improve the synthesis of protective metabolites. Therefore, providing short-term UV exposure during basil cultivation in vertical farming systems could help alleviate postharvest chilling injury (CI). We aimed to improve basil’s chilling tolerance during cold storage through the application of supplemental UV-B and UV-C at end-of-production (EoP). In this study, basil plants (cv. Dolly) that were grown in a vertical farming system with 200 µmol·m −2 ·s −1 red–white LEDs were exposed to supplemental EoP–UV-B (peak, 311 nm; 1.1 kJ·m −2 ·d −1 ) or EoP–UV-C (peak, 250 nm; 0.6 kJ·m −2 ·d −1 ) for 5 days. Harvested leaves were stored at 4 °C for 12 d. At harvest, both EoP–UV treatments reduced the fresh and dry weight of basil leaves by 9%. However, visual quality and CI symptoms of basil leaves during postharvest storage were unaffected by EoP–UV treatments, indicating no improvement in chilling tolerance. Metabolite profiling using 1 H nuclear magnetic resonance (NMR) revealed no significant changes in overall composition, particularly in phenolic antioxidants, under either EoP–UV treatment, despite a specific trade-off characterized by rising fatty acid and declining carbohydrate levels. These findings suggested that applied EoP–UV strategies did not improve the chilling tolerance of basil leaves, likely due to their inability to stimulate antioxidant accumulation, while the potential benefits of lipid remodeling were counterbalanced by the loss of osmo-protective sugars.