Synergistic Extraction and Antioxidant Activities of Ginger Polyphenols by Ultrasound Wave and Microwave

Abstract

Synergistic extraction technology of ginger polyphenols and antioxidant activities were studied. The extraction yield of total polyphenols with ultrasound wave and microwave synergistic extraction amounted to 4.66% of dry ginger and the content of 6-gingerol of ginger extract was up to 9.29%, whereas the extraction yield of total phenols with Soxhlet extraction for 2 hours for three times was no more than 3.48% of dry ginger and the content of 6-gingerol was only 4.02%. The antioxidant activities were investigated employing various established in vitro systems such as reductive power, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, hydroxyl radical scavenging activity and lipid peroxidation inhibitory activity. These scavenging abilities all increased with its increasing concentration, and the inhibiting effects to reductive power, DPPH radical and lipid peroxidation were markedly better than those of butylated hydroxytoluene (BHT), the inhibiting effect to hydroxyl radical was a less effective compared to BHT. All these results indicate that ultrasound wave and microwave synergistic extraction is a rapid extraction method with a good selectivity, and the ginger extract has good scavenging effect, compared with BHT, determine its potential as a natural preservative.