Abstract
Ethyl valerate (green apple flavor) production was investigated using immobilized Burkhoderia cepacia lipase by esterification of valeric acid with ethyl alcohol in a solvent system. Since the mechanisms of obtaining flavor esters using Bukholderia cepacia lipase are not well known, the synthesis of esters were studied in systems that contain organic solvent. The choice of the solvent was based on optimum result in the studies of lipase activity and stability in the presence of different solvents: alcohol, chloroform, toluene, hexane and heptane. In this case, the solvent which maintained increased activity and stability in the immobilized enzyme was heptane. For the experiments, the enzymatic extract was lyophilized and immobilized in solution of sodium alginate. The effect of acid to alcohol molar rate (0.1, 0.3 and 0.5 M) and the concentration of lipase (10, 20 and 30 % w/v) on the response esterification reaction were detected on the response of ester production yield. Aliquots were taken 0, 3, 6, 9, 12, 24, 48, 72 and 120 h and titrated with 0.02 M KOH and phenolphthalein used as indicator. The best result for obtaining ethyl valerate with yields almost 90 % was in 0.5 M and 20 % w/v.
