Impact of plasma activated water (PAW) on polyphenols, antioxidant properties, and anti-nutrients of sweet orange (Citrus sinensis) peel powder

Valorization of sweet orange (Citrus sinensis) peels into wealth technology by using the non-thermal process considered to be noteworthy. The present investigation was performed to study the impact of plasma activated water (PAW) on physicochemical properties, polyphenols, antioxidant activities (DPPH, FRAP), and anti-nutrients (phytic acid, tannin) of sweet orange peel powder. The sweet orange peel was soaked in PAW treated at 10 kV for 30 min followed by 1 h and 2 h followed by hot air drying at 40 °C. The results obtained that PAW treated samples T₁ (10 kV, 1 h soaking) and T₂ (10 kV, 2 h soaking) enhanced total phenols (270.36 ± 8.60; 291.07 ± 5.39), total flavonoids (201.71 ± 5.14; 237.15 ± 5.50), and antioxidant activities (37.55 ± 0.09; 39.32 ± 0.27) significantly. All physicochemical properties of PAW treated samples differed significantly. The reduction in the anti-nutrients in PAW treated samples was achieved as compared to control samples C₁ (1 h soaking in distilled water) and C₂ (2 h soaking in distilled water). Diffractograms revealed that an increase in the relative crystallinity might be due to action of reactive nitrogen species (RNS) and reactive oxygen species (ROS) generated in PAW. The potential application of PAW treated sweet orange peel powder can be used in the formulation of nutraceutical and functional novel food products.