Effect of Ultrasound, Steaming, and Dipping on Bioactive Compound Contents and Antioxidant Capacity of Basil and Parsley

Fresh basil and parsley leaves are perishable and they are often processed by drying, which is an energy-consuming process and contributes to nutrient degradation. These downsides can, however, be mitigated by various pre-drying treatments. Thus, the objective of this study was to assess the impact of different treatments (ultrasound, steaming, dipping) and their duration (20, 30 min) on contents of chlorophylls and lutein (analyzed by UPLC-PDA), total phenolic content (TPC), as well as antioxidant capacity (determined as DPPH radical scavenging activity) in basil and parsley leaves. The changes in the chemical properties after treatments were more significant in the case of basil than parsley, probably due to a lower thickness of leaf epidermis layer and stiffness of the former. In comparison to fresh leaves, enhanced extractability of chlorophyll a after all treatments and TPC after dipping for 20 min, was observed in basil. In parsley, instead, the chlorophylls content remained unchanged after treatments, but TPC decreased. Lutein content remained stable in both herbs following different treatments. Irrespectively of the treatment type, the TPC and antioxidant capacity were higher after 20 min of basil treatments, while in the case of parsley, higher TPC was determined after longer treatments (30 min). The study demonstrated that the investigated treatments could preserve or even enhance the chemical properties of herbs.