Optimization of Supercritical CO2 Extraction of Phenolic Compounds from Tomato (Solanum lycopersicum L.) Seeds Using...

Tomato seeds, a byproduct of the tomato-processing industry, are a rich source of bioactive compounds with promising nutritional and functional potential.

This study aimed to optimize the supercritical CO2 (SC-CO2) extraction of phenolic compounds from Solanum lycopersicum L. seeds using a full factorial design (FFD) within the framework of response surface methodology (RSM).

The effects of extraction pressure (100-500 bar) and temperature (40-80°C) were evaluated, with oil extraction yield and total phenolic content (TPC) as response variables. A one-factor-at-a-time (OFAT) approach assessed the effect of ethanol (0.25-1.0 mL) as a co-solvent under constant optimal extraction conditions. Derringer's desirability function was applied to identify simultaneous optimal conditions to maximize both responses. The main phenolic compounds were putatively annotated via HPLC coupled with a diode array detector and time-of-flight mass spectrometry (HPLC-DAD-TOF).

Extraction pressure and co-solvent volume significantly affected both oil extraction yield and TPC, while temperature primarily influenced yield. Multi-response optimization achieved an overall desirability value of 1.0 at 425 bar and 78°C with 1 mL ethanol, resulting in the highest oil extraction yield and phenolic recovery.

SC-CO2 extraction combined with desirability-based RSM is an efficient, green technique for valorizing tomato-processing residues, supporting circular bioeconomy principles through the sustainable recovery of high-value bioactives.

Optimized SC-CO2 extraction using RSM revealed that the factors most influencing oil extraction yield and the recovery of phenolic compounds were pressure and the quantity of co-solvents used. HPLC-DAD-TOF analysis putatively annotated the main phenolic compounds, thus emphasizing the sustainable valorization of byproducts from tomato processing.