Optimization of ethanol-assisted supercritical carbon dioxide extraction and spray-drying encapsulation of ginger bioactive from sabah ginger (Zingiber officinale)

Ginger (Zingiber officinale) contains bioactive compounds such as 6-gingerol that contribute to its antioxidant and functional properties. However, the recovery and stability of these compounds depend strongly on the extraction and post-processing methods employed. In this study, ethanol-assisted supercritical carbon dioxide (SCCO₂) extraction was applied to obtain bioactive compounds from Sabah ginger, followed by spray-drying encapsulation to enhance compound stability. The extraction process was conducted at temperatures of 40–80 °C and pressures of 10–30 MPa, and response surface methodology was used to determine the extraction condition that produced the highest yield. The optimum condition was identified at 40 °C and 20 MPa, with an extraction yield of 4.61%. The extract obtained under this condition also showed antioxidant activity of 80.77%, total phenolic content of 9.52 mg GAE/g, and total flavonoid content of 40.06 mg QE/g. The optimized extract was subsequently encapsulated by spray drying using maltodextrin as the carrier material. The spray-dried SCCO₂ extract exhibited improved retention of 6-gingerol (19.40 mg/g extract), while maintaining antioxidant activity (71.06%), total phenolic content (1.68 mg GAE/g extract), and total flavonoid content (25.83 mg QE/g extract). Field emission scanning electron microscopy revealed predominantly spherical microcapsules with relatively smooth surfaces, indicating successful encapsulation. The results demonstrate that the integration of optimized ethanol-assisted SCCO₂ extraction and spray-drying encapsulation is an effective strategy for recovering and stabilizing ginger bioactive compounds for potential functional ingredient applications.