INFLUENCE OF EXTRACTION CONDITIONS ON CONTENT OF BIOLOGICALLY ACTIVE SUBSTANCES FROM POMACE OF CABERNET SAUVIGNON AND RARA NEAGRA GRAPES

Abstract

Grape pomace contains many anthocyanins, catechins, flavonoids, phenolic acids, and stilbenes, so it must be utilized. The research used grape pomace from Cabernet Sauvignon and Rara Neagra, harvested in 2023. When creating the absorption spectra, a high content of anthocyanins was observed – components that describe the most significant increases in the spectral line at wavelengths between 510 and 550 nm, specific to these phenolic compounds, confirming the participation of anthocyanins in the formation of the color of grapes as main constituents. Studying the anthocyanin content showed that most pigments that gave the red color were found in acidulated samples of Cabernet Sauvignon, with an extraction temperature of 40°C. The same trend was observed in the acidulated extract of Rara Neagra with extraction temperatures of 40°C and 55°C. When determining the total phenolic content, values ranged between 4.59-5.16 mg GAE/g DW for Cabernet Sauvignon and 4.62-5.98 mg GAE/g DW for Rara Neagra. The antioxidant activity varied in Cabernet Sauvignon between 72.06-86.4%, and in Rara Neagra between 76.79-88.64%. The lowest values were recorded in the non-acidulated samples: 72% for Cabernet Sauvignon and 76.8% for Rara Neagra. As a result, acidulated extracts were the richest in biologically active substances.

Keywords

• anthocyanins
• extract
• phenolic substances
• grape pomace