Supercritical CO₂ and Conventional Extraction of Bioactive Compounds from Different Cultivars of Blackberry (<i>Rubus fruticosus</i> L.) Pomace

Abstract

The main objective of this work was to extract bioactive compounds from different cultivars of blackberry pomace using conventional Soxhlet and supercritical CO2 (SC-CO2) extraction methods. For Soxhlet extraction, two different solvents, ethanol and n-hexane, were used. Qualitative and quantitative composition of fatty acids was determined by GC, carotenoids and chlorophylls by HPLC, and volatile organic compounds were identified with an e-nose based on GC. The yield of the extract was influenced by the extraction, while the qualitative content of the extracts was also dependent on the cultivar. While there were no differences in the types of fatty acids extracted, their content varied significantly depending on the cultivar, extraction method, and their interaction. The results showed that linoleic acid (C18:2), oleic acid (C18:1), and α-linolenic acid (C18:3) were the most prevalent in all cultivars of blackberry pomace extracts. The linoleic acid content varied from 33.33 to 64.77% depending on the variety, and the ratio of omega-6 to omega-3 varied from 3.17% to 5.71%. Significantly higher quantities of carotenoids and chlorophylls were obtained in Soxhlet extraction with n-hexane in all extracts. The major carotenoid in the ‘Orkan’ and ‘Polar’ extracts was lutein, while in the ‘Brzezina’ extract, it was β-carotene. The extraction method has a significant impact on the flavor profile of the extracts.

Keywords

• blackberry pomace
• extracts
• fatty acids
• carotenoids
• chlorophylls
• volatile compounds