2nd Conference on Green Engineering, Sustainable Materials, and Technologies for Circular Economy (GREEN CIRC '25)

Extraction of grape waste from wine industry with subcritical Freon R134a

Not scheduled

20m

Amphitheatre (Faculty of Technology and Metallurgy, Ss Cyril and Methodius University in Skopje)

Poster presentation

Speaker

Dr Jana Klopcevska (Faculty of Technology and Metallurgy, Ss. Cyril and Methodius University in Skopje)

Description

The wine industry generates large quantities of grape waste, such as skins, stems, and seeds. Its composition, rich in phenolic substances, oils, and proteins, is highly valuable for obtaining various bioproducts.
In this study, the grape waste (skin and seeds with 1 mm particle size) from a winery in the Republic of North Macedonia was extracted with subcritical Freon R134a (1,1,1,2-tetrafluoroethane, C2H2F4) in a pilot scale plant (12 bar pressure, 45C temperature, 300 min extraction time, 20kg/h flow rate and 1000 g sample in extractor). The extract yield was determined. The composition and content of fatty acids (GC analysis), resveratrol content (LC-MS analysis), and antioxidant activity (DPPH method) were analyzed in the obtained extracts.
Higher extract yield was obtained from grape seeds (3.08%), compared to grape skin (1.98%). The total fatty acid content was 48.01 g/100 seed extract and 42.39 g/100 skin extract. Linoleic acid (C18:2) was the most abundant in the total fatty acid content, 67.01% and 58.85% for seed and skin extracts, respectively. The skin extract was richer in resveratrol (10.25%) and characterized by higher antioxidant activity (3.04%).
Keywords: grape waste, extract, fatty acids, resveratrol, antioxidant activity.