Enzymatic Synthesis of Lysophosphatidylcholine Containing γ-Linolenic and Stearidonic Acids in a Solvent-Free System

Stearidonic acid (SDA) and γ-linolenic acid (GLA) are recognized for their anti-inflammatory and cardiometabolic benefits, yet their natural dietary sources remain scarce. This study aimed to develop and optimize the enzymatic synthesis of lysophosphatidylcholine (LPC) enriched with GLA and SDA in a solvent-free system using Echium plantagineum seed oil as the source of GLA and SDA. Enzyme screening was conducted with three immobilized lipases, among which Lipozyme^® 435 exhibited superior performance, achieving significantly higher proportions of both GLA and SDA into the LPC backbone compared with alternative lipases. Reaction optimization was performed using a Box-Behnken response surface design, evaluating temperature, time, lipase load, and substrate molar ratio. The analysis identified lipase load as the most influential factor for both fatty acid proportion and LPC yield. At 50 °C for 24 h, with a substrate molar ratio of 1:15 and a 15 wt% lipase load, the synthesis yielded 92.0 ± 4.1 mol%. Within the LPC fraction, GLA + SDA contributed 69.5 ± 1.2% of total fatty acids. The resulting structured LPC combines the enhanced bioavailability of the lysophospholipid carrier with the complementary metabolic activities of GLA and SDA, supporting its potential for the development of functional foods and nutraceutical formulations.