Vanin Adriana B, Orlando Tainara, Piazza Suelen P, Puton Bruna M S, Cansian Rogério L, Oliveira Debora, Paroul Natalia
Department of Food Engineering, URI-Campus de Erechim, Av. Sete de Setembro, 1621, Erechim, RS, 99700-000, Brazil.
Department of Chemical and Food Engineering, Universidade Federal de Santa Catarina, UFSC, Campus Universitário, Bairro Trindade, Caixa Postal 476, Florianópolis, SC, 88040-900, Brazil.
Appl Biochem Biotechnol. 2014 Oct;174(4):1286-1298. doi: 10.1007/s12010-014-1113-x. Epub 2014 Aug 8.
This work reports the maximization of eugenyl acetate production by esterification of essential oil of clove in a solvent-free system using Novozym 435 as catalyst. The antimicrobial and antioxidant activities of clove essential oil and eugenyl acetate produced were determined. The conditions that maximized eugenyl acetate production were 60 °C, essential oil of clove to acetic anhydride ratio of 1:5, 150 rpm, and 10 wt% of enzyme, with a conversion of 99.87 %. A kinetic study was performed to assess the influence of substrates' molar ratio, enzyme concentration, and temperature on product yield. Results show that an excess of anhydride, enzyme concentration of 5.5 wt%, 50 °C, and essential oil of clove to acetic anhydride ratio of 1:5 afforded nearly a complete conversion after 2 h of reaction. Comparing the antibacterial activity of the essential oil of clove before and after esterification, we observed a decrease in the antimicrobial activity of eugenyl acetate, particularly with regard to minimum inhibitory concentration (MIC). Both eugenyl acetate and clove essential oil were most effective to the gram-negative than gram-positive bacteria group. The results showed a high antioxidant potential for essential oil before and particularly after the esterification reaction thus becoming an option for the formulation of new antioxidant products.
本研究报道了在无溶剂体系中，以诺维信435为催化剂，通过丁香精油的酯化反应实现乙酸丁香酯产量最大化。测定了所制备的丁香精油和乙酸丁香酯的抗菌和抗氧化活性。使乙酸丁香酯产量最大化的条件为：温度60℃，丁香精油与乙酸酐的比例为1:5，转速150 rpm，酶用量10 wt%，转化率为99.87%。进行了动力学研究，以评估底物摩尔比、酶浓度和温度对产物收率的影响。结果表明，酸酐过量、酶浓度为5.5 wt%、温度50℃、丁香精油与乙酸酐的比例为1:5时，反应2小时后转化率几乎达到100%。比较酯化前后丁香精油的抗菌活性，我们发现乙酸丁香酯的抗菌活性有所下降，尤其是最低抑菌浓度（MIC）方面。乙酸丁香酯和丁香精油对革兰氏阴性菌的效果均比对革兰氏阳性菌更好。结果表明，酯化反应前丁香精油具有较高的抗氧化潜力，酯化反应后抗氧化潜力尤其显著，因此可作为新型抗氧化产品配方的选择。
