Integrating Ozone Pretreatment in Green Extraction Techniques for Bioactive Compounds From Agro-Industrial Residues

The escalating challenges of agro-food waste management have driven research into sustainable extraction methodologies for efficient bioactive compound recovery. Conventional thermal and solvent-based methods often result in compound degradation, solvent toxicity, long extraction times, and low yields. In contrast, non-thermal strategies provide higher efficiency, reduced solvent use, shorter processing times, and better preservation of thermolabile compounds, enabling greener recovery processes. Ozone has emerged as an eco-friendly, non-thermal alternative with strong oxidative and cell-disruptive properties that enhance extraction performance. This review critically examines ozone's roles as pretreatment, direct extraction enhancer, and solvent activation agent in agro-food biomass valorization. Ozone facilitates cell wall disruption, mass transfer, and selective oxidation, improving recovery of polyphenols, flavonoids, carotenoids, and so forth. Furthermore, ozone modifies solvent polarity and reactivity, enhancing efficiency. Its integration with ultrasound, microwave, enzymatic, and supercritical fluid extractions offers promising potential for scalable, sustainable industrial applications. Unlike previous reviews, which mainly focused on ozone's lab-scale applications, this paper provides a novel and critical perspective by exploring ozone as a three-fold strategy. It uniquely discusses mechanistic insights and synergistic hybrid extractions and evaluates safety, environmental, and regulatory considerations that are often overlooked. While ozone-assisted extraction (OAE) technologies hold great potential, challenges such as compound stability, optimization of treatment parameters, and regulatory considerations require further exploration. This review highlights recent advancements in OAE and discusses industrial feasibility, economic concerns, and future research directions. By integrating ozone technology into bioactive compound recovery, agro-food waste valorization can contribute significantly in developing a circular economy and a more sustainable food industry.