Process Optimization of Enzyme-Assisted Extraction of Polysaccharides from Artificially-Cultivated Cordyceps cicadae and Its Kinetic, Thermodynamic and Antioxidant Activities Analysis

Objective: To optimize the enzyme-assisted extraction process of polysaccharides from artificially-cultivated Cordyceps cicadae was conducted in this study. Four different parameters were considered to evaluate the yield of polysaccharides including liquid to solid ratio, enzyme dosage, enzymatic temperature and extraction time. Methods: A four-factor-three-level experimental design was employed to establish a mathematical model by Box-Behnken method, and the scavenging capacity of polysaccharides against three radicals was examined. Afterward, Fick's second law was used to build the kinetic model for the extraction of polysaccharide from artificially-cultivated Cordyceps cicadae. The parameters including rate constants, relative extraction rate, and activation energy were employed to analyze the kinetic and thermodynamic features. Results: Based on the response surface analysis, the optimal extraction process was presented to be as following: Liquid to solid ratio 1:30 g/mL, enzyme dosage 1.6%, enzymatic digestion temperature 67 ℃ and extraction time 90 min. The polysaccharide yield under the above condition was 7.91%, which was close to the predicted value. Moreover, the results of antioxidant capacities indicated that the obtained crude polysaccharides under optimal conditions showed strong DPPH radical scavenging and hydroxyl radical scavenging with IC₅₀ values for 0.60 and 0.54 mg/mL, respectively, and its ORAC value was 45.62 Trolox μmol/g, suggesting potent antioxidant activity in vitro. Conclusion: The study of enzyme-assisted extraction of artificially-cultivated Cordyceps cicadae flower polysaccharides provide theoretical support for the production of polysaccharide fractions from this kind of commercialized Cordyceps cicadae resources.