Supercritical Fluid Extraction—A Sustainable and Selective Alternative for Tannin Recovery from Biomass Resources

Tannins are structurally diverse polyphenols prized for their antioxidant and protein-binding properties, making them valuable in leather tanning, adhesives, coatings, and water treatment. This article compares research on conventional versus supercritical fluid extraction (SFE), which is recognized as an eco-friendly and efficient technique. While SFE using supercritical CO2 is already widely studied and commercially implemented for various botanical compounds, its application to tannin extraction remains in an earlier stage of development, with limited industrial solutions currently available. Various solvents (CO2, water, ethanol, and methanol) and their mechanisms of action under supercritical conditions are discussed, demonstrating how adjusting parameters like pressure and temperature can selectively isolate specific tannin fractions. By reviewing multiple studies on yield, solvent choice, process efficiency, and product purity, the article highlights SFE’s advantages in preserving tannin quality while reducing energy consumption and contamination. The conclusions suggest SFE as a promising method for sustainable tannin production, offering tailored extracts that meet the growing demand for green processes in both industrial and biomedical applications.