Study On The Extraction Methods Of Ginkgolic Acids From Ginkgo Biloba Exopleura

In this paper, ultrasonic-assisted extraction （UAE）, microwave-assisted extraction （MAE） and supercritical carbon dioxide extraction （SC-CO₂） were applied to extract gingkolic （G.） acids from ginkgo biloba exopleura. The effects of the process were investigated by single-factor and response surface analysis experiments. Then the advantage and disadvantage of three extraction methods were compared. Finally, vacuum pyrolysis experiment was used to study biloba sclerotin exopleura in order to investigate the characteristic of pyrolysis behavior and the yield of bio-oil.Firstly, UAE was adopted to extract G. acids from the ginkgo biloba exopleura. Effects of several experimental parameters were investigated by single-factor experiments and RSM. The optimized conditions of UAE were as follows:sample powder 40-80 mesh, petroleum ether （60-90℃） as the extraction solvent, ratio of liquid-solid 11.3 mL g-1, ultrasonic time 65.0 min. Under these conditions, the experimental yield of G. acids was 69.58 mg g-1, which was well matched with the predicted value of 68.95 mg g-1 by RSM. Design-Expert 8.0.6 was used to analyze the experimental data. The stable and accurate mathematical model of UAE of G. acids from ginkgo biloba exopleura was established. The comparison experimental results indicated that the yield of G. acids by UAE was higher than that obtained from Soxhlet extraction.Secondly, MAE was adopted to extract G. acids from the ginkgo biloba exopleura. Effects of several experimental parameters were investigated by single-factor experiments and RSM. The optimized conditions of MAE were as follows:sample powder 40-80 mesh,61.5% ethanol aqueous solution as ruptured walls co-solvent （RWC）, volume of RWC 11 mL, microwave irradiation time 55 s, microwave power 336 W, petroleum ether （60-90℃） as the extraction solvent, extraction temperature 65℃, extraction time 86 min, ratio of solvent to material 10 mL g-1. Under these conditions, the experimental yield of G. acids was 78.59 mg g-1, which was well matched with the predicted value of 78.48 mg g-1 by RSM. Design-Expert 8.0.6 was used to analyze the experimental data. The stable and accurate mathematical model of MAE of G. acids from ginkgo biloba exopleura was established. The comparison experimental results indicated that the yield of G. acids by MAE was higher than that obtained from Soxhlet extraction.Thirdly, SC-CO₂ was adopted to extract G. acids from the gingko biloba exopleura. Effects of several experimental parameters were investigated by single-factor experiments and RSM. The optimized conditions of SCE-CO₂ were as follows:sample powder 40-80 mesh, 80% ethanol aqueous solution as modifier, volume of modifier 30 mL,1-2 h static-dynamic time, extraction temperature 46.1℃, extraction pressure 31.3 MPa, CO₂ flow rate 11 g min-1. Under these conditions, the experimental yield of G. acids was 74.90 mg g, which was well matched with the predicted value of 74.00 mg g-1 by RSM. Design-Expert 8.0.6 was used to analyze the experimental data. The stable and accurate mathematical model of SC-CO₂ ofG. acids from ginkgo biloba exoplura were established. The comparison experimental results indicated that the yield of G. acids by SC-CO₂ was higher than that obtained from conventional solvent extraction.Finally, the extraction yield of G. acids, technical maneuverability, and environmental effect of three extraction processes were compared. Based on an overall consideration of various factors, MAE was considered as the best extraction technology of G. acids from the ginkgo biloba exopleura.