Protein extraction from cold-pressed hempseed press cake: From laboratory to pilot scale

Area of Science:

• Food Science and Technology
• Biotechnology
• Sustainable Agriculture

Background:

• Industrial hempseed press cake (HPC) is a protein-rich byproduct of oil production, currently underutilized as animal feed.
• Extracting protein from HPC offers a sustainable solution to reduce food waste and increase plant-based protein sources for human consumption.
• The pH-shift method is a promising technique for isolating proteins from plant-based sources.

Purpose of the Study:

• To optimize a pH-shift method for enhanced protein extraction yield from industrial hempseed press cake (HPC).
• To evaluate the scalability of the optimized protein extraction process through a pilot trial.
• To determine the phytic acid content of the extracted hemp protein isolate and assess its implications for mineral absorption.

Main Methods:

• Laboratory-scale optimization of alkali extraction pH, time, temperature, and isoelectric precipitation pH.
• Pilot-scale trial to validate the optimized extraction process.
• Analysis of phytic acid content in the final protein isolate.

Main Results:

• Optimal laboratory conditions yielded 60.6% protein extraction with 90.3% purity (dry weight) at pH 10.5 (1 hour, room temperature) and pH 5.5 precipitation.
• Pilot trial demonstrated successful scale-up with 57.0% protein yield and 90.8% purity (dry weight).
• Phytic acid content was significantly reduced (83%-88%) in the protein isolate, comparable to other plant-based proteins.

Conclusions:

• The adapted pH-shift method effectively extracts high-purity protein from industrial hempseed press cake.
• The process is suitable for scale-up, offering a viable route for producing industrial hemp protein.
• Reduced phytic acid levels in the isolate suggest improved mineral bioavailability, making it a valuable ingredient for food applications.