Extraction of Flavonoids from Chickpeas by Microwave-assisted Eutectic Solvent and Its Antioxidant Activity

Using chickpea as raw material, choline chloride eutectic solvent as extraction agent, microwave-assisted technology was used to extract flavonoids in chickpea. The effects of hydrogen bond donor species, hydrogen bond donor and acceptor molar ratio, material-liquid ratio, eutectic solvent system water content, microwave output power, and microwave time on the yield of chickpea flavonoids were explored. Experiments and response surface optimization experiments determined the optimal process parameters for the extraction of flavonoids in chickpeas:Using choline chloride as the hydrogen bond acceptor and citric acid as the hydrogen bond donor to construct a eutectic solvent system. The molar ratio was 1:2, the water content of the eutectic solvent system was 30% (V/V), the material-liquid ratio was 1:22 g/mL, the microwave output power was 675 W, and the microwave time was 235 s. The rate was 2.49 mg/g, and the extraction rate could reach 90.55%, which was superior to the traditional alcohol extraction method.In vitro anti-oxidation experiments found that garbanzo flavonoids at different concentrations all had a certain reducing ability. With V_C as a positive control group, garbanzo flavonoids could significantly remove DPPH·, OH·and ABTS⁺·.With the increasing of flavonoids concentration, the clearance rate of DPPH free radicals by chickpea flavones showed an upward trend. When the flavonoid concentration was 0.05 mg/mL, the scavenging rate for OH·reached the maximum, which was 94.39%, and when the flavonoid concentration was 0.15 mg/mL, chickpea flavonoids had the highest ABTS⁺ free radical scavenging rate of 73.83%.In summary, flavonoids in chickpeas had a good antioxidant activity.