Optimization of extraction parameters, characterization and assessment of bioactive properties of Ziziphus lotus fruit pulp for nutraceutical potential

Ziziphus lotus fruits are consumed as food around the world and are highly valued for their distinctive flavor, nutritional and medicinal function. The functional properties of this fruit are attributed to the richness of bioactive compounds. Unfortunately, the extraction of these compounds and their inherent phytochemical characterization is rarely investigated under optimal extraction conditions. In this study, Z. lotus fruit pulp extracts rich in useful biocompounds in terms of its compositional and nutraceutical potential were obtained using heat-assisted extraction and response surface methodology. The optimal conditions were time: 71 min, temperature: 50 °C, solid to solvent ratio: 1:60 (g/mL) and ethanol concentration: 50% which gave 48.62% of yield, 106.64 mg Gallic acid equivalent (GAE)/g dry matter (DM) of reducing capacity with the Folin–Ciocalteu reagent (FCR), 49.65 mg quercetin equivalent (QE)/g DM of total flavonoid content (TFC), 179.33 mg Trolox equivalent (TE)/g DM of DPPH scavenging activity (DPPH), 150.02 mg TE/g DM of Ferric reducing antioxidant potential (FRAP) and 108.76 mg ascorbic acid equivalent (AAE)/g DM of total antioxidant activity (TAA). Under these conditions, a total of 38 compounds were identified using LC–ESI–MS/MS analysis. Furthermore, results showed that optimized extracts of Z. lotus fruit pulp possess good antibacterial activity. This study provides essential information of the potential application of useful and cost-effective method to recover bioactive compounds from Z. lotus fruit pulp that can be used as ingredient in functional food and nutraceutical products.