Extraction of anthocyanins from purple sweet potato using supercritical carbon dioxide and conventional approaches

•Ethanol-water-modified supercritical carbon dioxide (SCCO2) was used for extraction.•The extraction of phenolic compounds from purple sweet potatoes (PSP) was optimized.•Modified SCCO2 provided phenolic yields similar to those of methanolic extraction.•The dominant anthocyanins extracted by both methods were peonidin derivatives.•The SCCO2 extracts from PSP can be used as coloring agents in the food industry. This research investigates the potential of supercritical carbon dioxide (SCCO2) technology as a green and sustainable approach to improve anthocyanin extraction from purple sweet potatoes (PSP). The study explored different extraction parameters (i.e., temperatures of 35–55 °C, cosolvent concentrations of 10–30 % (w/w), ethanol ratios of 30–70 % (v/v), pressures of 30–40 MPa, extraction times of 120–180 min, and solvent: sample ratios of 25:1–45:1(v/w)), to optimize the total phenolic content (TPC), anthocyanin content (ANC), and antioxidant activity (AA). Additionally, conventional extraction methods using different solvent (ethanol and methanol) mixtures, solvent: sample ratios (15:1; 45:1; 6:1 (v/w)), temperatures (35–50 °C), and extraction times (50–60 min) were performed for the extraction of phenolic compounds from PSP. The highest TPC (340 mg GAE/g dry PSP), ANC (136 mg C3G/100 g dry PSP), and AA (ABTS (7.3 mg TEV/g dry PSP), DPPH (18.2 mg TEV/g dry PSP), and FRAP (1399 mg GAE/100 g)) were achieved with 30 MPa, 35 °C and 20 % cosolvent concentration operated for 180 min. These findings underscore the use of SCCO2 extraction to obtain anthocyanin extracts that can potentially be used as a coloring agent in the food industry. The proposed SCCO2 extraction method provides an eco-friendly alternative to conventional methods for extracting phenolic compounds. [Display omitted]