Extraction of antioxidant and antibacterial agents from avocado (Persea americana) seed using Pulsed Electric Field method

The abundance of avocado seeds causes environmental problems. Therefore, avocado seeds, which are high in bioactive compounds, have been utilized. Several extraction methods have been explored to maximize this utilization. However, conventional extraction methods present major challenges due to disadvantages such as requiring high temperatures, high energy consumption, long extraction times, and producing solvent waste. To that purpose, the Pulse electric field (PEF) extraction method was developed, which is highly efficient, has a short extraction process, is environmentally friendly, and does not produce solvent waste. This study observed the effect of electric field strength (2.5–7.5 kV/cm) and pulse frequency (100–250 Hz) until an optimum point on the properties of avocado seed extract (Avs) as an antioxidant and antibacterial agent. The results show that increasing the electric field strength and pulse frequency boosts the extraction yield and total phenolic content (TPC). This is highly supported by SEM images, which show more pores, cavities, and disrupted membrane cells as the electric field strength and pulse frequency increased. GC-MS and FTIR analysis also showed that the extract contains bioactive compounds such as polyphenols, fatty acids, and other compounds with the representing peaks OH, C−H stretch, C[dbnd]C, −C−H stretch, C−O stretch, and in-plan deformation vibration CH indicating as antioxidant and antibacterial agents. The extract obtained at 7.5 kV/cm with a pulse frequency of 250 Hz shows the best performance of bioactive potential indicated by antioxidant activity, IC₅₀, and surface area of the inhibition zone against E. coli and S. aureus, which are 95.56 %, 90 µg/mL, 396 mm², and 785 mm², respectively. The inhibitory zones of the two microbials were relatively stable until the seventh day of observation. This research showed that the EF extraction method serves as an eco-extraction technology of natural bioactive compounds, which has high potential application as an antioxidant and antibacterial agent.