Enzyme-assisted process for DAG synthesis in edible oils.

Area of Science:

• Biotechnology and Food Chemistry
• Enzymatic Synthesis and Oil Refining

Background:

• Diacylglycerols (DAGs) are valuable components in edible oils, often synthesized through chemical processes.
• Rapeseed oil contains significant free fatty acids (FFAs) that require reduction during refining.
• Enzymatic synthesis offers a potentially greener and more efficient route for DAG production and oil refining.

Purpose of the Study:

• To investigate and optimize the enzymatic synthesis of diacylglycerols (DAGs) in rapeseed oil.
• To evaluate the simultaneous reduction of free fatty acids (FFAs) during the enzymatic process.
• To explore the reusability of immobilized lipase and alternative acyl-group acceptors.

Main Methods:

• Enzymatic esterification of FFAs and monoacylglycerols (MAGs) using immobilized lipase from Rhizomucormiehei.
• Statistical design of experiments for systematic optimization of reaction conditions.
• Analysis of DAG content, FFA reduction, and lipase reusability through multiple batches.

Main Results:

• Optimized enzymatic synthesis achieved a maximum DAG content of 23% in rapeseed oil.
• Free fatty acid levels were significantly reduced from 2% to 0.3%.
• Immobilized lipase demonstrated reusability over 14 consecutive batches after washing with iso-propanol and hexane.
• Glycerol was identified as a viable alternative acyl-group acceptor to MAG, though with lower DAG yields.

Conclusions:

• Enzymatic synthesis is a promising alternative for producing DAG-enriched edible oils.
• The process effectively contributes to the refining of crude oils by reducing FFAs.
• Immobilized lipases offer a sustainable and reusable biocatalyst for industrial applications in oil modification.