关键词: 菊粉, 多糖, 超声波, 提取, 抗氧化

Abstract:

Helianthus tuberosus L. is a natural herb with excellent health care function. Ultrasound is widely used for auxiliary extraction of natural ingredients. Using dual-frequency countercurrent energy-gathered ultrasonic-assisted extraction technology, this paper studied the effect of ultrasound on extraction ratio and antioxidant activity of inulin polysaccharide, influence of each factor sorting order was power density > solid/liquid ratio > time > temperature > pulse/interval ratio. The optimum technology parameter was ultrasound dual-frequency combination of 20 kHz/35 kHz, ultrasound pulse/interval ratio of 4 s/3 s, ultrasound power density of 250 W/L, solid-liquid ratio of 1∶20, extraction temperature of 55℃ and extraction time of 15 min. Under this condition, the inulin extraction ratio was 56.35%, while under the same condition by hot water extraction method the extraction ratio was 33.89%. Inulin showed rather good antioxidant activity. Ultrasound had no obvious influence on antioxidant activity. Antioxidant activities of samples treated by diverse methods were significantly different, in which water crude extraction had the greatest·DPPH depleting capacity, and ultrasonic ethanol sediment showed the best reduction force and Fe2+ chelating ability, and the purified ultrasonic ethanol sediment had the highest hydroxyl radical scavenging rate.

Key words: inulin, polysaccharide, ultrasound, extraction, antioxidant