Turmeric Curcuma longa is a well-known spice with various health benefits, attributed primarily to curcumin. Soxhlet extraction, cold maceration, ultrasound-assisted extraction (UAE), and supercritical fluid extraction were performed, and the content of total phenols, proanthocyanidins, and antioxidants was analysed by UV/VIS spectrophotometry. High-performance liquid chromatography–tandem mass spectrometry (HPLC-MS/MS) was employed to identify and quantify the curcumin content. Supercritical extracts had the highest total phenolic content (538.95 mg GA/100 g material), while the Soxhlet extracts had the highest content of proanthocyanidins (4.77 mg PAC/100 g of material). Extracts obtained by UAE and supercritical extraction have the highest antioxidant potential. Antioxidant activity measured by 2,2-diphenyl-1-picrylhydrazyl (DPPH^•) was 64.27% and 1750.32 mg Trolox per g dry weight by 2,2-azinobis(3-ethylbenzothiazoline 6 sulphonic acid) (ABTS^+•) for the extract obtained by supercritical extraction. The UAE resulted in the highest amount of curcumin (1.91 mg curcumin/g material). A kinetic study showed that extraction yield in supercritical extracts decreased with increasing temperature and that the content of isolated curcumin was inversely proportional to solvent-to-feed ratio (S/F). The present study has confirmed that turmeric is an excellent source of antioxidants, such as curcumin, that play an important role in reducing cellular stress by neutralising free radicals.

This study reports the fabrication of curcuminoid-loaded nanofibrillated cellulose (NFC)–alginate scaffolds via extrusion-based 3D printing, integrating supercritical CO₂ extraction with biofabrication. NFC–alginate inks were pre-crosslinked with CaCl₂ (1 to 10 mM) to tune structure and properties. Rheological analysis confirmed shear-thinning behavior suitable for extrusion printing. Mechanical testing revealed a non-linear dependence on crosslinking: optimal performance was achieved by Ink 2 (1 mM CaCl₂ with curcuminoid extract), with tensile strength increasing from ~0.60 to ~0.80 MPa and Young’s modulus from ~1.5 to ~3.0 MPa relative (Ink 1, 10 mM CaCl₂, without extract), reflecting the combined effect of extract incorporation and ionic pre-crosslinking rather than crosslinker concentration alone; higher crosslinking reduced stiffness (~1.15 MPa). SEM revealed porous architectures (Ink 1: 542 ± 63 μm; Ink 4: 398 ± 71 μm) with increasing structural heterogeneity upon curcuminoid incorporation. In vitro release exhibited biphasic, diffusion-dominated behavior, reaching ~50 to 60% in ethanol-containing media; PBS inclusion as a physiological reference confirmed minimal release (<5%), consistent with the known hydrophobicity and pH-dependent instability of curcuminoids and defining the physicochemical delivery boundaries of the system. The highest release (~372 ng/mL) was achieved at intermediate loading (10×). Kinetic modeling confirmed Higuchi-type diffusion as the dominant mechanism (R² ≈ 0.90 to 0.99). These results establish a clear structure–property–release relationship and position the scaffolds as a tunable, diffusion-controlled delivery platform for hydrophobic bioactives in topical or formulation-assisted applications employing co-solvents or solubilizing excipients.