Postharvest blue LED light preserves peanut sprout quality by enhancing antioxidant capacity to inhibit browning

Postharvest browning is a major cause of quality loss in sprouts. Current preservation methods often rely on chemical treatments, which raise concerns about residues. Peanut sprouts with high moisture content and fragile structure are prone to browning during storage. This study investigated blue light-emitting diode (LED) light as a non-chemical alternative for controlling browning and preserving postharvest quality of peanut sprouts. Results demonstrated blue LED light treatment significantly preserved overall quality as indicated by a 1.14-fold higher ratio of commercially acceptable sprouts and a 1.28-fold greater hardness at 12 d. Browning was significantly suppressed, with browning index (BI) reduced to 0.65-0.85-fold and polyphenol oxidase (PPO) activity reduced to 0.80-0.89-fold of the control levels. The treatment also mitigated water loss and cellular disruption in hypocotyls, concomitant with reduced abscisic acid (ABA) accumulation. Moreover, blue LED light enhanced the antioxidant system, boosting the activities of key enzymes and the contents of non-enzymatic antioxidants. Consequently, reactive oxygen species (H 2 O 2 and O 2 · - ) and malondialdehyde (MDA, reduced to 0.57-fold) accumulation were significantly inhibited. These findings demonstrated blue LED light delayed browning in peanut sprouts primarily by enhancing antioxidant capacity to regulate ROS metabolism and reducing ABA accumulation, presenting a promising, residue-free strategy for postharvest preservation. • Postharvest blue LED light maintained overall quality of peanut sprouts. • Postharvest blue LED light inhibited the activity of PPO and browning of peanut sprouts. • Postharvest blue LED light enhanced antioxidant capacity to inhibit the levels of ROS. • HPLC analysis revealed blue LED light reduced ABA content of peanut sprouts.