Lipase-catalyzed concentration of stearidonic acid in modified soybean oil by partial hydrolysis

Stearidonic acid (SDA, 18:4 ω-3) content of modified soybean oil (MSO) containing ~25 % SDA, was increased by lipase-catalyzed hydrolysis. Four non-immobilized powdered lipases, Lipase AY 30 (Candida rugosa), Lipase G 50 (Penicillium camembertii), Lipomod™ 34P-L034P (Candida cylindracea [rugosa]), Lipomod™ 36P-L036P (Rhizopus oryzae), and an immobilized lipase, Lipozyme RM IM (Rhizomucor miehei) were assessed, at various incubation times, for their ability to hydrolyze MSO and specificity toward SDA. The SDA enriched products contained triacylglycerols (TAG), diacylglycerols (DAG) and monoacylglycerols (MAG). Lipase 34P-L034P exhibited specificity towards SDA, while Lipase AY was able to discriminate against it. The highest total SDA content (40.9 mol%) was obtained with Amano AY lipase at 4 h incubation (66.2 % hydrolysis). Unhydrolyzed TAG, 1,3-DAG, 2,3(1)-DAG, and MAG contained 37.7 (56.4 at the sn-2 position), 41.6, 51.5 (54.9 at the sn-2 position), and 49.9 % SDA, respectively. Amano AY lipase was also used to hydrolyze previously SDA-enriched TAG (48.7 % SDA) obtained from low temperature crystallization of MSO. The highest total SDA content (62.7 mol%) was obtained at 12 h incubation (85.9 % hydrolysis). The SDA contents of unhydrolyzed TAG, 1,3-DAG, 2,3(1)-DAG, and MAG were 58.7 (65.7 at the sn-2 position), 71.2, 70.2 (52.9 at the sn-2 position), and 59.4 %, respectively.

The authors would like to acknowledge the grant from Monsanto Company (St. Louis, MO).

Peer Reviewed