Green Valorization of Two-Phase Olive Pomace via Pressurized Liquid Extraction: Process Optimization, Comprehensive...

Area of Science:

• Food Science
• Analytical Chemistry
• Natural Product Chemistry

Background:

• Olive pomace is a rich source of bioactive phenolic compounds.
• These compounds possess antioxidant and antimicrobial properties, making them valuable for food applications.
• Developing efficient extraction methods is crucial for utilizing these natural resources.

Purpose of the Study:

• To evaluate pressurized liquid extraction (PLE) for obtaining antioxidant and antimicrobial extracts from olive pomace.
• To optimize extraction parameters, including temperature and solvent composition.
• To characterize the phenolic compounds and assess the extract's efficacy as a food preservative.

Main Methods:

• Pressurized liquid extraction (PLE) using a combined static/dynamic procedure.
• Face Centered Central Composite Design to optimize temperature (100-140 °C) and ethanol concentration (50-100%).
• Analysis of Total Phenol Content (TPC), antioxidant capacity (TEAC), chemical composition (RP/HPLC-Q-TOF MS/MS), oxidative stability (Rancimat), and antimicrobial activity (MIC).

Main Results:

• Optimal extraction conditions were 120 °C with 60-80% ethanol, yielding maximum TPC and TEAC.
• RP/HPLC-Q-TOF MS/MS identified 37 compounds, including quinic acid, elenolic acid, and oleuropein derivatives.
• The extract (120 °C, 75% ethanol) increased sunflower oil's induction period by 2.4-fold and showed antimicrobial activity (MIC 3.6 mg/mL).

Conclusions:

• PLE is an effective method for extracting valuable phenolic compounds from olive pomace.
• Olive pomace extracts demonstrate significant antioxidant and antimicrobial potential.
• These extracts can serve as natural preservatives, improving food safety and shelf-life.