Abstract:
Polyphenols have the ability to scavenge reactive oxygen species and protect tissues against oxidative damage. However, the extraction, enrichment mechanisms, and antioxidant activities of rouge radish polyphenols (RRP) remain poorly understood. This study aims to elucidate the key factors in extraction, enrichment mechanisms, and the characteristics of antioxidant activity. Response surface methodology was employed to optimize the probe-type ultrasonic-assisted extraction process. Resin enrichment mechanisms were investigated through adsorption/desorption kinetics and isothermal adsorption model. Antioxidant activity of RRP before and after enrichment was analyzed using the DPPH, ABTS
+, and ferric reducing antioxidant power assay to provide theoretical support for the efficient development and antioxidant research of RRP. Results indicated that probe-type ultrasound significantly enhanced RRP yield compared to plate-type ultrasound and shaking-bed extraction (
P<0.05). Optimal parameters were: extraction solvent concentration 60% ethanol, solid-to-liquid ratio 1:55 g/mL, extraction temperature 55 ℃, ultrasonic power 350 W, and extraction time 20 min, yielding 33.03±0.12 mg/g. The adsorption/desorption process of HPD-400 resin were conformed to be the pseudo-second-order model, and the intraparticle diffusion was primary but not the sole rate-limiting step. Temkin model was more suitable for describing the adsorption behavior, and lower temperature was beneficial for adsorption. After enrichment, the Scavenging Concentration values for RRP in scavenging 2,2-Diphenyl-1-picrylhydrazyl and 2,2'-Azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt radicals decreased to 35.5% and 83.0% of their pre-enrichment levels, respectively, while the Ferric Reducing Antioxidant Power Assay value increased by 1.3-fold.