Antioxidants from Luxembourgish grape pomace for dietary supplements

Abstract Background Recent efforts in business and research have increasingly focused on recycling local waste for biorefineries. This article presents the results of scaling and adapting polyphenol extraction from local grape pomace (GP) to produce dietary supplements with antioxidant properties. A secondary goal was to utilize as much biomass as possible, e.g. sugars. Results Scaling the extraction process required many parameters to be changed. However, temperature, duration and water or a 3:1 water–ethanol solution as the maceration solvent remained. The grinding process was optimized to ensure a reproducible particle size distribution. The net‐filter combination (200 and 100 μm) was then defined based on this and considering GP swelling. Calcium chloride was added to the solvent to bind pectin and diatomaceous earth, maintaining an open filter cake. The GP concentration during maceration was also increased. Post‐extraction processing through thermal concentration, centrifugation and freeze‐drying yielded polyphenol sugar extracts with a low antioxidant power compared to laboratory extracts. These extracts and their test formulations for dietary supplements were highly hygroscopic. De‐sugaring the aqueous filtrate using an adsorbent resin resulted in an ethanolic polyphenol extract with an antioxidant activity comparable to that of laboratory extracts. Conclusion The GP maceration scaling proceeded in a straightforward way. Isolating a product for optimal biomass utilization yielded a highly hygroscopic, unsuitable extract with low antioxidant power, likely due to thermal stress during volume reduction. Processing the aqueous filtrate with an adsorber resin produced an ethanolic polyphenol extract with good antioxidant power, meeting the formulation requirements for dietary supplements. © 2025 Society of Chemical Industry (SCI).