Multi-response Optimization of Ultrasonic Assisted Enzymatic Extraction of Antioxidant Polysaccharides from Waste Ginkgo biloba Sarcotesta

The combination of Plackett-Burman design (PBD) and rotatable central composite design (RCCD) was used to optimize ultrasonic assisted enzymatic extraction (UAEE) for achieving maximal recovery of antioxidant polysaccharides from waste Ginkgo bilobasarcotcsta (GBSP). After the combination of PBD and RCCD, the resulting optimal UAEE conditions were as follows: UAE power of 239 \X', time of 31 min, cellulase concentration of 3.2%, UAE temperature of 60 degrees C, pH of 4.5, solvent-to-solid of 30 mL/g and sample particle size of 60 mesh. Under the optimum conditions, the experimental yield of GBSP was 7.71 +/- 0.53 % (n = 3) and ferric-reducing antioxidant capacity values of GBSP was 22.43 +/- 1.93 mmol Fe2+; /g (n = 3), which were close to the above predicted values. Moreover, the antioxidant activities of GBSP(UAEE) obtained by UAEE compared with GBSP(HWE) obtained by hot water extraction (HIVE), the antioxidant activities obtained using GBSP(UAEE) were significantly higher than those GBSP(HWE). Additionally, the carbohydrate content, monosaccharide composition and IR spectrum of the GBSP(UAEE) were also investigated. Therefore, the present study provided an advisable method of UAEF, for extraction of antioxidant GBSP from waste Ginkgo biloba resource.