Assessment of the polyphenol recovery from white wine lees via non-ionic polymeric resins

Abstract

Wine lees, a significant by-product of the wine industry, are an underutilized but valuable resource for nutraceutical recovery, as they are rich in bioactive compounds, particularly polyphenols. This study introduces a novel and eco-friendly method for extracting and purifying polyphenols from white grape wine lees. Solid-liquid extraction was conducted using water and a 25 % w/w ethanol-water hydroalcoholic solution, resulting in aqueous (Aq) and hydroalcoholic (HA) extracts. Five food-grade, non-ionic polymeric resins (XAD7HP, XAD16HP, MN202, PAD900, and PAD950) were evaluated for polyphenol purification. Resin MN202 emerged as the most effective for this purpose.

Under static conditions with the Aqueous extract, the MN202 resin achieved an adsorption ratio (AR) of up to 60.5 % and a desorption ratio of 97.9 %, yielding a total adsorption-desorption efficiency (TADY) of 59.2 %. In contrast, the TADY for glucose and fructose was minimal at just 0.36 % and 11.25 %, respectively, highlighting the resin's high selectivity for separating polyphenols from sugars. Adsorption isotherms (Langmuir, Freundlich, Sips, and Redlich-Peterson) followed the Langmuir isotherm model, indicating monolayer adsorption. Both adsorption and desorption conformed to pseudo-second-order kinetics, dominated by multilayer intraparticle diffusion. Under dynamic conditions, polyphenol recovery decreased to 44 %, though the purified polyphenols remained suitable for high-value applications. Overall, this process potentially provides a promising and sustainable approach for recovering polyphenols from wine lees, with strong potential for scaling and use in nutraceutical and antioxidant products.