Highly purified pinolenic acid from pine nut oil: A novel approach combining urea complexation, lipase-catalyzed esterification, and rapid preparative reversed-phase liquid chromatography

Pinolenic acid (PLA) from pine nut oil was purified through a three-step process involving urea complexation (UC), lipase-catalyzed selective esterification, and rapid preparative reversed-phase liquid chromatography (RP-RPLC). UC was optimized with response surface methodology (RSM) under optimized conditions: fatty acid/urea (w/w) of 1:3.114, 95 % ethanol/urea (B, v/w) of 3.892:1, complexation time (h) of 12.303, and complexation temperature of −9.84 °C, achieving the optimal concentration of 62.19 ± 0.33 % and the yield of 46.55 ± 0.43 %. The one-step purified PLA was further purified through lipase-catalyzed selective esterification, resulting in purity and yield at 81.50 ± 0.32 % and 45.83 ± 0.2 % for the two-step purified PLA. The two-step purified PLA was then eluted from a C18 column to achieve the product with purity of 99.52 ± 0.08 % and yield of 71.93 ± 0.03 %. This study introduces an innovative PLA purification strategy for high-purity products suitable for nutritional and pharmaceutical uses.