Аннотация
The supercritical hybrid carbon dioxide-hydrogen (Sp-CO 2 H 2 ) extraction was evaluated for the first time as a hybrid solvent system for the recovery of phytochemicals from grape seeds, utilising response surface methodology (RSM), mathematical modelling, and optimisation techniques. In this system, a pressure-resistant cylindrical vessel was used in the supercritical extraction reactor to maintain stable, controlled phase conditions. The independent variables P-t-T (pressure, temperature, time) were optimised using RSM and mathematical modelling and optimisation (MMO) techniques to improve the extraction efficiency of phenolic substances (TPC) and antioxidants. A CO 2 /H 2 mixture (96/4% vol equivalent to 24:1 mol/mol) was used as an antioxidative solvent, with water serving as a polar modifier. The optimisation conditions were determined within the studied ranges of pressure (60–80 bar), extraction time (5–9 min), and temperature (30–60 °C), and the optimal point was established at 60 bar, 5 min, and 60 °C. Under the optimum conditions, the total phenolic content (TPC) was 124.02 mg gallic acid equivalents/100 mL, while the individual phenolic compounds determined by HPLC were catechin (292.38 mg/L), epicatechin (163.16 mg/L), gallic acid (3.61 mg/L), and chlorogenic acid (lowest concentration). Accordingly, catechin was the most abundant individual phenolic compound, whereas chlorogenic acid was the least abundant. Antioxidant activity reached 76.66% 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 86.74% 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS), and the total phenolics quantified by HPLC (sum of identified phenolics) was 613.09 mg/L. Under optimised conditions, the Sp–CO 2 – H 2 method is more effective than the classical Sp-CO 2 method in extracting phenolic compounds and antioxidants from Cimin grape seeds. It has increased the TPC, DPPH, and ABTS values of the extracts by 35%, 2%, and 17%, respectively. It has also increased the epicatechin and catechin phenolic components by 79% and 45%, respectively. The results suggest that Sp-CO 2 H 2 extraction can be a valuable, sustainable process for recovering bioactive compounds from agri-food waste, such as grape waste.