Abstract:

Ginger oleoresin was extracted from dried ginger powder using supercritical CO2 fluid with the addition of absolute ethanol as a colsolvent. The effects of extraction pressure, extraction temperature, extraction time, particle size of material and amount of absolute ethanol on extraction yields of ginger oleoresin and gingerols were investigated by single factor and orthogonal array methods. The optimum conditions for ginger oleoresin extraction were determined as the follows: particle size of dried material, below 120 mesh; extraction pressure, 35 MPa; extraction temperature, 35 ℃, and extraction time 2.5 h. Under these conditions, the extraction yield of ginger oleoresin and gingerols reached 6.08% and 2.78%, respectively. Ginger oleoresin could effectively scavenge DPPH free radicals in a significant dose-dependent manner. GC-MS analysis indicated that there were 76 compounds identified in ginger oleoresin, of which 16 ones might belong to the gingerol family and the relative content was 33.95%. These results suggest that ginger oleoresin is rich in antioxidant components as gingerols.

Key words: ginger oleoresin, supercritical CO2, technological study, antioxidant activity, gas chromatography-mass spectrometry