Optimizing antioxidant and thermal stability in olive mill wastewater through Hydroxypropyl-β-Cyclodextrin complexation: A comprehensive study

• OMWW molecules successfully incorporated into HP-β-CD cavities • HP-β-CD enhances OMWW's antioxidant activity and thermal stability • OMWW/HP-β-CD-IC (MR 1:2) shows superior properties over other ratios • HP-β-CD is a nontoxic, biodegradable oligosaccharide improving OMWW properties • Inclusion complexation of OMWW in HP-β-CD could add value to industrial waste The study investigates the enhancement of thermal stability and antioxidant activity of olive mill wastewater (OMWW) by complexing it with hydroxypropyl-beta-cyclodextrin (HP-β-CD) in different molar ratios (1:1, 1:2, and 1:3). OMWW is rich in phenolic compounds with significant antioxidant properties but suffers from low bioavailability and thermal sensitivity. The inclusion complex formation was assessed using FT-IR, XRD, and DSC analyses. FT-IR results showed the disappearance of O-H stretching vibrations in the 1:2 molar ratio complex, indicating successful interaction. XRD confirmed the absence of OMWW's characteristic peaks, and DSC revealed that the melting point of OMWW increased from 192.3°C to 211.1°C, 228.0°C, and 224.7°C for the 1:1, 1:2, and 1:3 ratios, respectively, demonstrating improved thermal stability. The 1:2 molar ratio complex exhibited the highest antioxidant activity and phenolic content. SEM and 1 H NMR spectroscopy further validated the successful formation of the inclusion complex. The OMWW/HP-β-CD complex, especially at the 1:2 ratio, shows promise for use in pharmaceutical products and fortified foods due to its enhanced stability and antioxidant properties.