Upcycling Winery Waste into Functional Cosmetic Ingredient: Green Recovery of Squalene fromWine Lees as a Potential In Vitro Permeation Enhancer

Squalene and squalane are widely used cosmetic ingredients valued for their emollient properties and excellent skin compatibility, yet sustainable sourcing remains a challenge. This study presents an integrated and eco-friendly strategy for valorizing wine lees as a renewable source of squalene and converting it into stable, high-performance squalane. Squalene was efficiently recovered from yeast-rich winery waste through optimized ultrasoundassisted extraction, followed by chromatographic purification. Green catalytic hydrogenation using palladium supported on natural clay minerals enabled the selective conversion of squalene into squalane under mild conditions. The functional evaluation via in vitro transport studies across an artificial membrane, using quercetin as a poorly permeable model antioxidant, demonstrated enhanced permeation compared with conventional vehicles, while accelerated aging experiments further confirmed the superior oxidative stability of squalane relative to native squalene. Overall, this work provides a proof of concept for upcycling winery by-products into multifunctional cosmetic ingredients that combine sustainability, stability, and functional performance, supporting circular economy principles and the growing demand for ethically sourced raw materials in the cosmetic industry.