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Description
Grape pomace represents an important winery by-product with significant potential for valorization as a source of minerals and bioactive compounds. In this study, an aqueous extract of grape pomace obtained from the autochthonous Serbian cultivar Prokupac was analyzed in order to evaluate its mineral profile determinate by ICP-OES method and phytochemical composition determined by LC–MS analysis. The plant material was prepared by drying the grape pomace and seeds in a drying oven at 40°C, followed by grinding in a mill. Subsequently, an aqueous extract of the plant material (1:20, w/v) was obtained at 50°C for 30 minutes using a magnetic stirrer. The extract was then centrifuged and filtered through 0.45 μm filters. The mineral profile, expressed in ppm, showed that phosphorus, calcium and magnesium were the dominant elements, with concentrations of 96.9, 84.2 and 32.66 ppm, respectively. Lower concentrations of silicon, sodium, iron, zinc, copper and manganese were also detected, indicating the presence of nutritionally relevant macro- and microelements. Cadmium, arsenic and lead were not detected, which is favorable from the perspective of potential application in food, nutraceutical or cosmetic products. LC–MS analysis revealed the presence of several bioactive compounds, including tartaric acid, taxifolin, gallic acid hexoside, aromadendrin isomer, dihydrophaseic acid hexoside, p-coumaric acid hexoside, quercetin hexoside, syringetin hexoside, isorhamnetin hexoside, trihydroxy-octadecenoic acid and dihydroxy-octadecadienoic acid. The detected compounds belong mainly to organic acids, phenolic acid derivatives, flavonoids and oxidized fatty acid derivatives, which may contribute to the antioxidant and functional potential of the extract.
The obtained results indicate that aqueous extraction can be an effective and environmentally acceptable approach for recovering mineral constituents and polar bioactive compounds from Prokupac grape pomace. This supports the potential use of this by-product as a sustainable raw material for the development of value-added food, nutraceutical or cosmetic formulations within the concept of circular bioeconomy.
Keywords: Prokupac; grape pomace; aqueous extract; minerals; ICP-OES, LC–MS.