本研究基于单因素实验并结合Box-Behnken设计优化闪式提取无花果总黄酮的工艺,通过考察乙醇体积分数、提取电压、液料比以及提取时间等因素对总黄酮提取的影响,获得无花果总黄酮闪式提取的最佳条件,并对其抗氧化活性进行了研究。结果表明,响应面优化无花果总黄酮的最佳提取工艺条件为:乙醇体积分数50%,液料比50:1 mL/g,提取时间80 s,提取电压150 V。在此条件下无花果总黄酮的提取量为(36.94±0.02) mg/g,与预测值36.98 mg/g误差仅为0.103%,证实了结果的准确可靠。抗氧化实验显示无花果总黄酮对DPPH自由基的清除效果优于抗坏血酸,而对ABTS+自由基的清除效果弱于抗坏血酸,其对OH自由基清除的IC50为0.098 mg/mL,与抗坏血酸(IC50为0.159 mg/mL)相比,黄酮对OH自由基的清除效果更好。闪式提取无花果总黄酮提取量较高且耗时更短,表明闪式提取法应用于无花果黄酮提取更具优势。无花果总黄酮具有较好的抗氧化活性,有望为功能性食品或保健品的开发提供理论基础。
Flash extraction of total flavonoids from Ficus carica L. was investigated in this study. Based on the single factor experiments, four extraction parameters including ethanol concentration, extraction voltage, liquid-to-liquid ratio and extraction time were tested and optimized by Box-Behnken design (BBD) experiments. The results showed that the optimal extraction conditions were:Ethanol concentration of 50%, liquid-to-liquid ratio of 50:1 (mL/g), extraction time of 80 s, and extraction voltage of 150 V. The extraction yield of total flavonoids reached (36.94±0.02) mg/g under the optimized conditions, which was much close to the predicted value (36.98 mg/g), which confirmed the accuracy and reliability of the BBD. The antioxidant experiments showed that fig flavonoids had better scavenging effect on DPPH radicals than ascorbic acid, while the capacity on scavenging ABTS+ free radicals was less effective than ascorbic acid. The IC50 of total flavonoids on scavenging OH free radicals was 0.098 mg/mL, compared with ascorbic acid (IC50 was 0.159 mg/mL), the total flavonoids had a better scavenging effect on the OH free radicals. As compared to conventional method, flash extraction may serve as a better extraction technology for recovery of flavonoids from figs on considering both the extraction yield and extraction time. Furthermore, fig flavonoids revealed strong antioxidant activity and could provide a theoretical basis for the clevelopment of functional foods and ingredients.