Recovery of Bioactive Compounds from Industrial Exhausted Olive Pomace through Ultrasound-Assisted Extraction

Area of Science:

• Agricultural Chemistry
• Biotechnology
• Green Chemistry

Background:

• Exhausted olive pomace (EOP) is a significant agro-industrial waste from olive oil extraction.
• EOP contains valuable bioactive compounds such as phenolic compounds and mannitol.
• Valorization of EOP is crucial for sustainable waste management and resource recovery, especially before its use as biofuel.

Purpose of the Study:

• To optimize ultrasound-assisted extraction (UAE) for recovering antioxidant compounds from EOP.
• To evaluate the efficiency of both bath-type and probe-type UAE systems.
• To identify and quantify key bioactive compounds, including hydroxytyrosol and mannitol, in the extracts.

Main Methods:

• Box-Behnken experimental design was employed to optimize bath-type UAE parameters (acetone concentration, solid load, extraction time).
• Response surface methodology was used to determine optimal extraction conditions.
• A two-level factorial experiment design evaluated probe-type UAE (amplitude, extraction time) for faster extraction.

Main Results:

• Optimal conditions for bath-type UAE were 40% acetone, 8.6% solids, and 43 min, yielding significant antioxidant content.
• Probe-type UAE achieved comparable phenolic compound yields in a significantly shorter time (12 min at 70% amplitude).
• Hydroxytyrosol was identified as the major phenolic compound, with mannitol also quantified in the extracts.

Conclusions:

• Ultrasound-assisted extraction is an effective technology for valorizing EOP into valuable bioactive compounds.
• Probe-type UAE offers a time-efficient alternative for industrial-scale extraction, reducing operational costs.
• The recovered bioactive compounds (hydroxytyrosol, mannitol) can be utilized for various applications before EOP is used as biofuel.