Unlocking hot trub's potential: a simple method for extracting bitter acids and xanthohumol

Area of Science:

• Brewing By-products Valorization
• Phytochemical Extraction
• Green Chemistry

Background:

• Hot trub, a brewing by-product, is rich in nutrients but underutilized.
• Reprocessing hot trub offers potential for sustainable resource recovery.

Purpose of the Study:

• To investigate the extraction of bitter acids and xanthohumol from hot trub.
• To identify key parameters influencing the extraction efficiency.

Main Methods:

• Utilized a Plackett-Burman design to assess extraction parameters.
• Evaluated effects of pH, ethanol concentration, temperature, and solid-to-liquid ratio.
• Analyzed phytochemical concentrations and characterized solid residues.

Main Results:

• Ethanol concentration and pH significantly impacted bitter acid and xanthohumol yields.
• Maximum bitter acid concentration reached ~16 mg/g (β-acids), and xanthohumol reached 239 μg/g.
• Extraction patterns for phytochemicals were similar, suggesting comparable interactions with macromolecules.

Conclusions:

• Ethanol concentration is the primary driver for extracting bitter acids and xanthohumol.
• Temperature did not significantly affect extraction yields.
• The resulting solid residues show potential as a protein source.