Dehydration Impact on Antioxidant Potential and Phenolic content of Backhousia citrodora leaves

The most popular method for food preservation is dehydration. In order to enhance the overall quality and prolong the longevity of herbal products, it is imperative to carefully choose optimal dehydration conditions. The dehydration of Backhousia citriodora, also known as lemon myrtle leaves (LML), was conducted via three distinct techniques: conventional dehydration at temperatures of 40, 50, and 60°C (referred to as CD40, CD50, and CD60, respectively); vacuum dehydration at the same temperature as conventional dehydration with a pressure of 50 mbar; and heat pump dehydration at a constant temperature of 45°C. The antioxidant capacities, specifically the radical scavenging activity (DPPH) and ferric reducing antioxidant power (FRAP), along with the total phenolic content (TPC), were evaluated. HPD samples came up second to VD samples in terms of TPC retention, DPPH activity, and FRAP test, whereas CD samples had the lowest biochemical content across all dehydration conditions. The TPC and antioxidant activity in the CD sample exhibited a substantial reduction as the dehydration temperature increased. After dehydration, the CD60 sample had the largest reduction in TPC, DPPH, and FRAP values. Maximising the retention of biochemical content is of utmost importance in post-harvest processing as it serves as an indicator of greater retention. Therefore, the selection of appropriate dehydration techniques and conditions is critical in achieving this objective.