Abstract
Plant-derived antioxidants are valuable for their health benefits and roles as natural preservatives in foods, cosmetics, and pharmaceuticals. Green extraction methods have gained prominence as sustainable, efficient, and safe alternatives to conventional solvent-intensive techniques. Supercritical fluid extraction (SFE), particularly with CO₂, has emerged as an important green technology for recovering antioxidants from plant materials. This review provides a comprehensive overview of SFE principles and advantages, compares SFE with traditional extraction methods, and summarizes key antioxidants (polyphenols, carotenoids, tocopherols) obtained from various plant sources (fruits, vegetables, herbs, agro-industrial wastes) via SFE. Industrial case studies in food, cosmetic, and nutraceutical sectors are discussed, including economic and scalability considerations and regulatory/safety aspects. While SFE offers higher selectivity and often improved yields with negligible solvent residues, challenges such as high capital costs and technical complexity persist. Recent innovations – from hybrid extraction systems and process intensification strategies to AI-driven optimization – are highlighted as future directions to enhance SFE efficiency and integration at industrial scale. These advancements position SFE as a key enabling technology for sustainable production of natural antioxidants, aligning with the growing demand for green processes and clean-label products.
Introduction
Plant-based antioxidants (e.g. polyphenols, carotenoids, tocopherols) are widely used for their ability to scavenge free radicals and prevent oxidative damage. They play crucial roles in extending shelf life of foods, in anti-aging skincare formulations, and in health-promoting nutraceuticals and pharmaceuticals. With consumers seeking “natural” and safer alternatives to synthetic antioxidants, there is intense interest in extracting these bioactive compounds from botanical sources (Tyśkiewicz, Konkol et al. 2018, Uwineza & Waśkiewicz, 2020). However, traditional extraction techniques (such as solvent maceration, Soxhlet extraction, and steam distillation) often have drawbacks: they are time-consuming, use large volumes of organic solvents, may degrade heat-sensitive compounds, and can leave toxic solvent residues in extracts (Uwineza & Waśkiewicz, 2020, Carpentieri, Soltanipour et al. 2021). This has driven the need for green extraction methods that are more sustainable and efficient. Green extraction emphasizes reduced energy consumption, replacement of petrochemical solvents with eco-friendly ones, and safer, higher-quality extracts (Uwineza & Waśkiewicz, 2020, Carpentieri, Soltanipour et al. 2021). In recent years, several novel “greener” extraction technologies have been developed, including ultrasound-assisted extraction (UAE), pressurized liquid extraction (PLE), microwave-assisted extraction (MAE), subcritical water extraction, and supercritical fluid extraction (SFE) (López-Padilla, Ruiz-Rodriguez et al. 2017, Uwineza & Waśkiewicz, 2020, Stasiłowicz-Krzemień, Wójcik et al. 2024, Yıldırım, Erşatır et al. 2024). Among these, SFE using supercritical CO₂ has gained particular prominence as a versatile and environmentally benign technique for recovering natural antioxidants and other bioactives (Uwineza & Waśkiewicz, 2020).
Supercritical fluid extraction involves using fluids at conditions above their critical temperature and pressure, where the fluid exhibits unique solvent properties – combining liquid-like solvating power with gas-like diffusivity (Carpentieri, Soltanipour et al. 2021). CO₂ is the most commonly used supercritical solvent due to its moderate critical point (31 °C, 74 bar), non-toxicity, non-flammability, low cost, and GRAS (Generally Recognized As Safe) status (Uwineza & Waśkiewicz, 2020, Carpentieri, Soltanipour et al. 2021, Le-Tan & Jaeger, 2022). These attributes make SFE especially suitable for sensitive plant antioxidants that might be degraded by high temperatures or harsh chemicals. This review provides an in-depth examination of SFE as a green extraction method for plant-based antioxidants. We first explain the principles of SFE with CO₂, including key mechanisms and operational parameters, and compare its performance with conventional extraction techniques. We then survey major classes of plant antioxidants (polyphenols, carotenoids, tocopherols) and their plant sources that have been successfully extracted via SFE, noting factors that influence yield and quality. Industrial applications of SFE are discussed through case studies in the food, cosmetic, and pharmaceutical sectors, along with considerations of economic feasibility, scalability, and regulatory safety. The review also examines current challenges that limit the broader adoption of SFE and outlines future directions. These include hybrid extraction systems, co-solvent optimization, process intensification, and machine-learning-based modeling to improve sustainability and industrial integration. Overall, supercritical CO₂ extraction is highlighted as a key green technology for transforming plant-based resources into high-value antioxidant ingredients.
Several reviews have examined the use of green extraction methods for antioxidants, including those (Tyśkiewicz, Konkol et al. 2018, Uwineza & Waśkiewicz, 2020, Quitério, Grosso et al. 2022) which discuss general advancements in SFE and other emerging extraction techniques. However, many of these works provide limited industrial perspective or lack integration of recent innovations such as artificial intelligence-based optimization, hybrid systems, and life-cycle assessments. More recent reviews like Bhadange, Carpenter et al. (2024) have emphasized broader bioactive recovery but do not focus specifically on antioxidant compounds or their regulatory and economic feasibility.
Our review addresses these gaps by combining technical, industrial, economic, and sustainability dimensions of SFE for antioxidant recovery.
This review was conducted by performing a comprehensive literature search across major scientific databases, including Scopus, Web of Science, ScienceDirect, and Google Scholar. The following search terms were used in various combinations: “supercritical fluid extraction,” “plant-based antioxidants,” “CO₂ extraction,” “green extraction,” “bioactive compounds,” and “natural product recovery.”
We focused on peer-reviewed original research articles, reviews, and case studies published between 2010 and 2025. Studies were selected if they:
- Investigated SFE using CO₂ (with or without co-solvents) for extracting antioxidants from plant matrices;
- Compared SFE to conventional or emerging green techniques;
- Reported quantitative data (yield, purity, antioxidant activity, process conditions);
- Provided insights into industrial applications, sustainability, or scalability.
After an initial screening of relevant literature, a substantial number of scientific publications were reviewed in detail, with the most pertinent studies selected to support the analysis and discussion presented in this manuscript.
Read more here
Hoang Le Tan, Green Extraction of Plant Antioxidants: Supercritical Methods and Industrial Applications – A Review, Food and Humanity, 2025, 100787, ISSN 2949-8244, https://doi.org/10.1016/j.foohum.2025.100787.
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