檸檬精油儲存於檸檬皮的油腺細胞內，通常以冷壓榨法或水蒸餾法萃取而得，其成分中含有上百種有機物，以萜烯類為主，由於具有清新芳香的氣味以及良好的生物活性，在應用方面十分廣泛，例如芳香療法、抗菌劑、抗氧化劑、香水、營養品……等，普遍的商品應用使得檸檬精油需求量大增，因此檸檬精油的萃取效率逐漸成為重要的課題。本研究目的為提升檸檬精油萃取效能，並期望能使檸檬精油有良好的應用性，故選擇水蒸餾法萃取以利分離精油，使用混合界面活性劑Tween 40與Tween 85輔助以提高萃取效率，同時以反應曲面法的實驗設計，使實驗參數能有系統地達到最佳化。在應用方面，鑒於檸檬精油天然無毒且具有抗菌活性，故本研究以食品保鮮包裝為目的，添加精油於高分子薄膜中，探討其抗菌與機械性質。
經過實驗設計得到界劑輔助萃取的最佳化條件為：界劑濃度為1545.5 ppm，萃取時間為156.3分鐘，液固重量比為15；驗證實驗也證實反應曲面法所建立模型的預測性，且最佳化條件下產率可提升至約2倍之多；以動力學模擬萃取過程，顯示界劑輔助法有較高的質傳係數，證實可改善萃取效能；以GC-FID分析精油中的六種主成分，比較不同萃取方法間精油組成的差異，結果表明界劑輔助法與一般水蒸餾法成分並無明顯差異；精油溶解度測試中，檸檬精油溶解度隨著界劑濃度呈線性增加，且溶解度高於市售檸檬精油，並在0.3wt%檸檬精油於5wt%界劑溶液的配方中，有最良好的穩定性；抑菌活性實驗結果顯示，檸檬精油對E. coli與S. aureus有抗菌性，且效果優於市售檸檬精油，而由殼聚糖/界面活性劑(CS)添加檸檬精油製成的薄膜中，對S. aureus展現抑菌效果。

Recently, due to the good biological properties, the wide applications of lemon oil (LO) increase its demand. Thus, the efficiency of extracting lemon oil becomes a concerning topic. In this study, surfactant-enhanced-hydrodistillation with a mixture of Tween 40 and Tween 85 was employed to speed up the rate of LO extraction, as well as to separate LO easily. Also, response surface methodology (RSM) was applied to systematically optimize the parameters of extracting process, which were surfactant concentration, extracting time, and liquid/solid ratio in this study. The solubility and stability of LO emulsion were investigated for the application of LO-added polymer films as active packaging. Moreover, the antibacterial property of LO was evaluated.
Results showed that the optimal condition was 1545.5 ppm as the concentration of surfactant Tween 40/Tween 85 mixed in 3/1, 156.3 min for extraction time, and liquid/solid ratio at 15. Under these conditions, according to the fitted second-order polynomial model, the response Y was predicted to be 30.14. A kinetics model simulated the extraction process and displayed a higher mass transfer coefficient in the presence of surfactant assisting. Composition analysis by GC-FID and HPLC indicated no difference between LOs from the two hydrodistillation processes. The solubility of LO appeared linear increasing with surfactant concentration and is was higher than commercial lemon oil (CLO) due to the different compositions. A microemulsion formed when 0.3% LO in 5% surfactant solution and can maintain its stability for more than 28 days. The antibacterial test illustrated the good activity of LO against E. coli and S. aureus, even better than CLO, in addition, the chitosan/surfactant film with LO showed antibacterial activity against S. aureus.

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