Drying is a widely used method to produce dried prunes, effectively extending the shelf life of plums. Prunes are susceptible to water loss, rapid ripening, softening, and decay after harvesting, which results in significant wastage of fruit resource (Stanley et al., 2013). However, drying plums presents challenges due to the development of the cuticular waxy layer during growth, which significantly affects the dehydration process (Cinquanta et al., 2002). Furthermore, the large volume, high pectin content, and high sugar content of plums lead to prolonged drying times and issues during the drying process (Huang et al., 2019). As a result, achieving optimal dehydration time and maintaining quality during drying pose significant challenges in prune production.

Assisted non-thermal techniques are utilized in fruit and vegetable drying to disrupt the waxy layer on the surface of berry fruits, aiming to improve the drying efficiency and quality (Sun et al., 2019). Pulsed electric field (PEF), as an alternative and effective non-thermal treatment, shows significant potential in fruit and vegetable drying (Ciurzynska et al., 2023; Llavata et al., 2024; Matys et al., 2024; Zhang, Fang, et al., 2023). The low electric field intensity of PEF pre-treatment does not significantly enhance the efficiency of drying, whereas high electric field intensity treatment can result in irreversible cell electroporation, leading to excessive loss of nutrients. Therefore, combining previous research (Chen et al., 2025; Santos et al., 2023), our study selected three gradient levels of electric field intensity (1, 3, 5 kV/cm) for PEF treatment before hot-air drying. PEF pre-treatments have been shown to improve hot-air drying rate (Giancaterino et al., 2024; Kim et al., 2023), and their impact on the overall content of certain nutrients has been studied to some extent (Bao et al., 2024). However, a comprehensive understanding of the PEF-induced changes in nutrients and their molecular metabolic mechanisms under drying dehydration stress remains unclear.

Freah plums are distinguished by their distinctive metabolic products, particularly polyphenols, renowned for their potential effectiveness in treating autoimmune diseases (Khan et al., 2019), combating anti-inflammatory (Mileo et al., 2019), and managing diabetic complications (Raina et al., 2023). Anthocyanins is a subgroup of flavonoids abundant in fruits, particularly dark fruits like prunes (Liu & Zhang, 2024). Polyphenols and anthocyanins serve as pivotal substrates for the antioxidant activity of fresh prunes, constituting essential sources of functional active compounds (Khallouki et al., 2012; Ozzengin et al., 2023; Zhang et al., 2024). Not only fresh plums but also dried prunes have been shown to exhibit significant antioxidant capacity (Tagliazucchi et al., 2010; Yener et al., 2024). However, while several studies have reported on the antioxidant activity of prunes, research elucidating the specific material basis underlying this activity remains insufficient. Moreover, the molecular mechanisms underlying metabolite involvement in antioxidant changes during pretreatment and drying stress remain unclear. Although there is research on the changes in polyphenols and anthocyanins during plum growth, the stress-induced alterations in nutrients during drying and PEF pre-treatment are not well-established.

Therefore, the main object of the study was to investigate the influence of different PEF intensities on the drying kinetics of plums, total phenolic and flavonoid contents, as well as antioxidant capacity, uses widely-targeted and anthocyanin-targeted metabolomics to investigate the effects of PEF and drying on polyphenols and anthocyanins. Subsequently, the effects of polyphenol and anthocyanin metabolism on the antioxidant capacity of plums under drying conditions were explored to reveal the molecular mechanism of changes in the antioxidant capacity of prunes.