Pulsed light irradiation improves degradation of ginkgolic acids and retainment of ginkgo flavonoids and terpene trilactones in Ginkgo biloba leaves

Although high temperature processing is a traditional physical processing method used to degrade ginkgolic acid (GA) in Ginkgo biloba L., it leads to loss of abundant bioactive compounds in G. biloba leaves (GBL) such as ginkgo flavonoids, ginkgolides, etc. Pulsed light (PL) is a prospective non-thermal technique that might be a possible solution to the above problem. In this research, the impact of PL and heating pretreatment on GA, ginkgolides and bilobalide, flavonoid profile, polyphenol oxidase (PPO) and peroxidase (POD), antioxidant capacity, and total phenolics content (TPC) of GBL was evaluated. Besides, an ultrahigh-performance liquid chromatographyquadrupole/orbitrap High-resolution mass spectrometry (UPLC-Q-Orbitrap HRMS) was employed to gain insight into the degradation pathway of GA C13:0. The findings showed that fluences of 0.52 J/cm2 for 300 s reduced GA by 19.94%, while heating at 180 degrees C for 300 s only reduced the GA by 7.04%. Moreover, the ginkgo flavonoids and terpene trilactones (bilobalide and ginkgolides A to C) in GBL were effectively retained after PL irradiation but significantly reduced by heating at 180 degrees C. Ginkgo leaves irradiated by PL for 200 s had the highest antioxidant capacity and TPC, while heating produced opposite results. Pulsed light and heating treatments significantly inactivated PPO and POD, but PL preserved color of leaves (lower total color change). UPLC-Q-Orbitrap HRMS results showed that PL irradiation degraded GA C13:0 by removing the hydroxyl or carboxyl group of the benzene ring. These findings demonstrate that PL treatment can improve quality of GBL, opening a broader way for its applications in food industry.