Optimization of medium chain length fatty acid incorporation into olive oil catalyzed by immobilized Lip2 from [i]Yarrowia lipolytica[/i]
Résumé
Triacylglycerols (TAG) enriched with medium chain fatty acids (M) present specific nutritional, energetic and pharmaceutical properties. Structured lipids (SL) were produced by acidolysis between virgin olive oil and caprylic (C8:0) or capric (C10:0) acids in solvent-free media, catalyzed by the main extracellular lipase from Yarrowia lipolytica lipase 2 (YLL2), immobilized in Accurel MP 1000. Response surface methodology was used for modeling and optimization of the reaction conditions catalyzed by immobilized YLL2. Central composite rotatable designs were performed as a function of the reaction time (2.5-49.5 h) and the molar ratio of medium chain fatty acid/TAG (MR; 0.6-7.4), for both acids, and also of temperature (32-48 degrees C) for C8:0 experiments. As for capric acid, the incorporation of caprylic acid in olive oil showed not to depend of the temperature, within the tested range. The response surfaces, fitted to the experimental data, were described by a first-order polynomial equation, for C8:0 incorporation, and by a second-order polynomial equation for C10:0 incorporation. Under optimized conditions (48 h reaction at 40 degrees C, with a molar ratio of 2:1 M/TAG) the highest incorporation was reached for C8:0 (25.6 mol%) and C10:0 (21.3 mol%).