Response Surface Methodology Optimization of Microwave-Assisted Polysaccharide Extraction from Algerian Jujube (Zizyphus lotus L.) Pulp and Peel

Abstract

Purpose The active ingredient recovery from the vegetable is a very attractive research field for the development of a sustainable economy; to revalue the jujube fruit (Zizyphus lotus) polysaccharide (ZLPS), an optimized green microwave-assisted method was used for the recovery and enrichment of the antioxidants present in a distilled water extract. Methods A series of 17 experiments including microwave power, irradiation time, and liquid-to-solid ratio independent parameters was designed by the response surface methodology to optimize the recovery of the polysaccharide extract. Results The optimal conditions were as follows: 600 W, 40 min, and 26.69 mL/g. Under these conditions, the experimental extraction yield was 13.98 ± 1.55% which is very close with the predicted value (14.08%), and this demonstrated the validation of the extraction model proposed. The polysaccharide extract exhibited a significant scavenging activity against ABTS.+ (70.45%), DPPH*.(66.02%), and FRAP (A = 0.63) with a very important anti-inflammatory activity using a protein denaturation method that showed a maximum inhibition of 95.33% at 200 μg/mL. Additionally, the membrane stabilization method showed a significant action and protection of human red blood cells (85.76%) in hypotonic-induced lysis solution and 86.45% in heat-induced lysis solution. Conclusion This study demonstrated the possibility of exploiting the microwave process to obtain extracts remarkably enriched with invaluable antioxidants from the jujube matrix. The operation time is short, and the antioxidant and anti-inflammatory activities of the distilled water extract were preserved.