Superheated liquids for extraction of solid residues from winemaking processes

Area of Science:

• Green Chemistry
• Biomass Valorization
• Separation Science

Background:

• Winemaking generates substantial solid residues, presenting a waste management challenge.
• These residues contain valuable compounds like phenolics and fatty acids.
• Traditional extraction methods can be slow and inefficient.

Purpose of the Study:

• To develop and optimize a superheated water-ethanol extraction method for winemaking solid residues.
• To characterize the compounds obtained from the extraction process.
• To evaluate the efficiency and speed of the new method compared to traditional approaches.

Main Methods:

• Extraction using superheated water-ethanol mixtures under optimized conditions (65 min, 210°C).
• Compound identification and characterization via spectrophotometry, gas chromatography (GC-FID, GC-MS), and high-performance liquid chromatography (HPLC-UV).
• Static extraction with single or repeated cycles, with parameter optimization (pressure, temperature, solvent ratio, pH).

Main Results:

• The optimized method successfully extracted valuable compounds from winemaking residues.
• Extracts separated into an aqueous phase rich in phenolic compounds and an oily phase rich in fatty acids.
• Extraction parameters like pressure, temperature, water-to-ethanol ratio, and pH allow for tunable extract composition.

Conclusions:

• Superheated water-ethanol extraction is an effective and rapid technique for isolating phenolic compounds and fatty acids from winemaking solid residues.
• The method offers a sustainable approach to valorize agro-industrial byproducts.
• This optimized process provides a faster alternative to conventional extraction procedures.