PARTIAL HYDROLYSIS OF SOYBEAN OIL BY PHOSPHOLIPASE A1 TO PRODUCE DIACYLGLYCEROL-ENRICHED OIL

Partial hydrolysis of soybean oil catalyzed by phospholipase A₁ (Lecitase Ultra) in a solvent-free system was carried out to produce a diacylglycerol (DAG)-enriched soybean oil. Five reaction parameters of partial hydrolysis were investigated. The upper oil layer of the reaction mixture was molecularly distilled at 150C to yield a DAG-enriched oil with 42.64 (wt%) of DAGs. DAG-enriched oil was distilled a second time at 250C to yield a DAG oil with 78.68 (wt%) of DAGs. The composition of acylglycerols in the DAG-enriched soybean oil was determined by high-performance liquid chromatography (HPLC) and HPLC/electrospray ionization/mass spectrometry. The released fatty acids from the partial phospholipase A₁ hydrolysis of soybean oil showed a higher saturated fatty acid content than that of the raw material. Compared with other lipase-catalyzed processes, this new phospholipase A₁ preparation has the advantage of reducing production of monoacylglycerol byproduct.

PRACTICAL APPLICATIONS

Diacylglycerols (DAGs) are esters of glycerol in which two of the hydroxyl group are esterified with fatty acids. Studies on both animals and humans have shown the beneficial health effects of DAG. DAG is a generally-regarded-as-safe foodstuff by the U.S. Food and Drug Administration and is approved as a substitution for triacylglycerol in fats and oils in many developed countries. In this work, partial hydrolysis catalyzed by phospholipase A₁ (Lecitase Ultra) in a solvent-free system was firstly used to produce DAG-enriched soybean oil. Compared with the lipase-catalyzed process, this new phospholipase A₁ showed the advantage of low cost and low byproduct monoacylglycerol production. The new process has a potential application in the commercial production of DAG oil.