Sunflower Lecithin Hydrolysis by Phospholipase A1. Effect of Reaction System

GOÑI, M. L.; CONSTENLA, D.T.; CARELLI, A. A.

Phoenix, Arisona, USA.

Congreso; 101st AOCS Annual Meeting&Expo; 2010

AOCS

<!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0in; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman"; mso-ansi-language:ES; mso-fareast-language:ES;} @page Section1 {size:8.5in 11.0in; margin:1.0in 1.25in 1.0in 1.25in; mso-header-margin:.5in; mso-footer-margin:.5in; mso-paper-source:0;} div.Section1 {page:Section1;} --&aThe effect of the reaction system on the sunflower-lecithin enzymatic hydrolysis by free phospholipase A1 was studied. The reaction system consisted on buffer, substrate (67% of phospholipids, 0.5% water and 32.5% oil) and enzyme in a ratio of 4mL:80mg:1mL. The reaction was carried out in a batch reactor, maintaining time and temperature fixed at 1h and 50ºC, respectively. The effect of pH (5 and 8), addition of calcium ions (0 and 0.24mg/mL) and solvent (0 and 240mg/mL) in the reaction medium was considered. The hydrolysis degree (H%) was determined by titration of liberated fatty-acids (FFA), previously extracted from the reaction medium. The FFA profile generated by hydrolysis was determined by capillary gas chromatography using the internal standard method, procedure which involves lipid extraction, clean up and fatty-acid methyl-esters preparation. Results demonstrated than the use of solvent in the reaction medium causes a decrease in the H%, for any of the parameter combinations, presenting values of H% between 1.5% and 14%, compared with a range of H%= 9%-34% obtained by free-solvent reaction. When the pH and the presence of calcium ions are evaluated, the most affecting parameter was the pH. At pH 5, the highest values of H% were obtained (34% and 28% depending on the addition or not of calcium ions, respectively).