Effect on lipoxygenase pathway and flavor stabilization of postharvest strawberries by intense pulsed light treatment

Abstract

A non-thermal pretreatment method was developed to improve the flavor stability of strawberries using an intense pulsed light during postharvest storage. The physicochemical properties, volatile organic compounds (free and bound), enzyme activities, and key gene expressions were investigated during 7-day storage. A 23.67% decrease in the decay ratio was obtained in IPL-treated with 2.0 Hz frequency for 60 s compared to the control. A more stable surface color was obtained at the end of the storage period. A total of 21 f-VOCs and 13 b-VOCs were quantitatively identified. IPL treatment promoted the contents of free aldehydes, esters, and ketones. The content of (E)− 2-heptenal in the IPL-treated strawberries was 1.90 times higher than that in control. The variation in the total content of b-VOCs was less than 31.61% that in the control group. Correspondingly, IPL treatment inhibited the activities of fatty acid metabolism enzymes and decreased LOX activity by 26.3% after storage. Aroma-related genes, including FaLOX, FaADH, and FaAAT, were down-regulated in the metabolism of specific VOCs following IPL treatment. This work provided evidence about the practical application of IPL in inhibiting the activity of enzyme in the LOX pathway, thereby improving the flavor stability of strawberries under non-thermal process conditions.