Kinetic study of sunflower-lecithin hydrolysis using Phospholipase A1

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

Phoenix, Arizona, USA.

Congreso; 101st AOCS Annual Meeting and Expo; 2010

American Oil Chemists' Society (AOCS)

The effect of temperature and time on solvent-free sunflower-lecithin enzymatic hydrolysis by free phospholipase A1 (PLA1) was studied. The reaction was carried out in a batch reactor, at two different temperatures (50ºC and 60ºC). The reaction medium consisted in a mixture of buffer (pH=5), lecithin (67% of phospholipids, 0.5% water and 32.5% oil) and enzyme in a ratio of 4mL: 80mg: 1L. An aliquot of this reaction mixture was taken for analysis at different times (1-24h). The liberated fatty-acids were extracted and titrated in order to determine the hydrolysis degree. The free-fatty acid (FFA) profile generated by hydrolysis was determined by capillary gas chromatography using the internal standard method, with a previous FFA extraction, clean up and methyl-esters preparation. The results show a notable difference between the two temperatures considered, even at short reaction times. When the reaction is carried out at 60ºC, the variation of hydrolysis degree (H%) is very low (from 25% to 30% approximately) and the maximum value is achieved at short reaction times (t = 3h). In contrast, a wide range of H% (30% to 60% approximately) was observed at 50°C.The highest hydrolysis degree (60% at 20h) was obtained at this temperature.