Lime peel as an industrial resource: Improving the extraction efficiency of volatiles and polyphenols via cold plasma

Lime (Citrus aurantifolia) is among the most widely used fruits due to its high nutritional value and abundance of bioactive compounds. However, its high consumption results in significant waste such as peel, which itself is rich in valuable bioactive compounds including essential oils and flavonoids that have diverse applications in the food, pharmaceutical, and cosmetic industries. Given the critical role of extraction methods in maximizing compound recovery, the present study aimed to investigate the effects of two cold plasma (CP) pretreatment methods-dielectric barrier discharge (DBD) and glide arc discharge (Glide)-on the extraction efficiency of bioactive compounds from lime peel. To this end, lime peel samples were subjected to seven different treatments: DBD for 4, 6, and 10 minutes, and Glide for 90, 120, and 150 seconds and control. The evaluated parameters included essential oil yield and composition (by GC/MS), polyphenolic compounds (by HPLC), flavones and flavonols content, total phenolic content, total flavonoid and antioxidant activity. The results demonstrated that CP pre-treatment positively influenced the extraction of these functional compounds. Among the DBD treatments, DBD for 10 minutes showed the highest efficiency, while Glide for 120 seconds outperformed the other Glide treatments in enhancing most of the studied phytochemical attributes.