Process intensification of essential oils extraction using instantaneous controlled pressure drop technology

• Explores CID as a novel intensification method for essential oil extraction. • Benchmarks CID against traditional and emerging extraction technologies. • Summarises global research on CID across plant types and process variables. • Details process design, equipment, and key operational steps of CID. • Outlines EO quality testing, post-treatment, and analytical techniques. Essential oils (EOs) are volatile, hydrophobic compounds derived from plants, widely used in food, cosmetic, pharmaceutical, and fragrance industries for their bioactive potential and associated health benefits. Traditional EO extraction methods are limited by low yields, long processing times, and thermal degradation of sensitive bioactive compounds. Instantaneous Controlled Pressure Drop (CID) technology is an advanced intensification method to overcome these challenges by applying compression-decompression cycles and modifying plant structure to enhance heat and mass transfer. This review provides a comprehensive analysis of CID technology and outlines its mechanism and principles. It compiles global research on CID applied to different plants and compares the technology with conventional and emerging extraction techniques. A process flow diagram is provided to illustrate the operational stages of CID system, including steam injection, vacuum decompression, emulsion collection, and post-treatment. It discusses technical configurations, and explores coupled phenomena of autovaporisation, heat and mass transfer, and resolution of the extraction paradox. CID improves extraction efficiency and high-quality of EOs by overcoming rate-limiting barriers of traditional methods. It addresses extraction paradoxes by reversing vapour pressure gradients and leveraging total pressure for optimal recovery. CID compatibility with conventional methods shows synergistic potential for industrial scalability for greener EOs extraction processes.