99A-10 |
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Y.-F. Ling1, H.-F. Liao2, and C.-J. SHIEH1. (1) Department of Bioindustry Technology, Dayeh University, 112 Shan-Jiau Road, Changhua, 51505, Taiwan, (2) Department of Medical Research, Mackay Memorial Hospital, 45 MingShan Road, Tamshui, Taipei County, 251, Taiwan Phenolic acids are widely known as efficient antioxidants in biological systems. Generally, the solubility of natural antioxidants might be a restriction to the practical applications in hydrophobic media. Therefore, the esterification of phenolic acid with alcohol can be a tool to alter physical solubility properties and activity of the lipophilic antioxidants in oil based formulae and emulsions. Phenols can be converted into esters by esterification with acid chlorides or acid anhydrides; however, these routes do not meet the requirements necessary for food applications. Recently the esterification of organic acids via enzymatic routes has been successfully reported in some studies. Our purposes were to understand the relationships between the factors (reaction time, temperature, enzyme amount, and dipping buffer) and the yield (percent molar conversion), and to determine the optimal conditions for phenolic acid esters synthesis using central composite rotatable design (CCRD) and response surface methodology (RSM) analyses. In this work, phenolic acid esters synthesis was carried out in screw-capped test tubes without added solvent. Hydroxyphenylpropionic acid and octanol were catalyzed by different amounts and pH value of enzyme. The mixtures were stirred in an orbital shaking water bath at different reaction temperatures and reaction times. Our results showed that reaction time, temperature and enzyme amount were the most important variables. Based on ridge max analysis, the optimum synthesis conditions with 96% molar conversion were: reaction time 58 h, temperature 53 ¢XC, enzyme amount 38 % (w/w), and buffer pH 7. These results show the ability for immobilized Candida antarctica lipase (Novozyme 435) to catalyze the esterification of hydroxyphenylpropionic acid and octanol.
Session 99A, Biotechnology: General
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