Enzimatik yolla yüzey aktif maddelerin üretimi ve özelliklerinin incelenmesi

Propyl laurate and lauric acid esters of fructose were produced by using immobilized lipase (Novozym 435). Molecular sieve was used to shift the reaction towards the synthesis. In the first part of the work, the optimum working parameters of the enzyme for the production of propyl laurate were investigated. The mono, -di and higher esters of lauric acid with fructose were obtained and analyzed qualitatively and quantitatively by HPLC. After the purification of products by column chromatography, the surfactant properties (HLB value, critical micelle concentration, surface tension and emulsion stabilization) were evaluated experimentally. According to the results, maximum amount of propyl laurate was obtained when isopropyl alcohol was used. The product formation was followed by a linear increase up to lauric acid concentration of 5 mmole. The maximum activity was obtained at 60°C. The amount of product seemed to be linearly proportional to enzyme concentration up to 50 mg. There was a linear increase in the amount of propyl laurate up to 50 min of reaction time. The amount of esters was observed to vary depending on the ratio of lauric acid to fructose and the reaction time. The HLB value of propyl laurate, fructose monolaurate and fructose dilaurate were calculated as 3.5, 8.95 and 5.3, their CMC values were calculated as 6.84 x 10"4 M, 7.20 x 10"5 M and 6.40 x 10"5 M, iiirespectively. The CMC values of esters obtained from conductivity curve and surface tension curve were similar to each other. It was found that when the concentration of surfactant increased, the stabilization of emulsion also increased. Fructose dilaurate showed better stability than the other esters. Results showed that, these enzymatically prepared and purified substances have the properties of general surfactants. In addition, their use in food industry was found to be suitable depending on the advantages such as use of natural sources in their production, ease of purification and modification, absence of toxic impurity in the final product. They are also harmless to the environment because they are biodegradable. Key words : Candida antarctica lipase, esterification, surfactants, emulsifiers, lauric acid, fructose