Abstract

The orange tree (Citrus sinensis) is a species of fruit shrubs of the Rutaceae family. Essential oils from citrus peels are widely used in various agro-food and pharmaceutical preparations and hence they must be recovered using green extraction methods. In this study, we compare the efficiency of five extraction techniques (conventional hydro-distillation (HD), Salt-assisted extraction by HD (S-HD), Ultrasound-assisted extraction by HD (US-HD), Enzymes-assisted extraction by HD (E-HD), and Solvent-free microwave extraction (SFME)) for the extraction of essential oil from Citrus sinensis peels. The essential oils were compared with regard to their chemical compositions, light microscopy analysis, total energy consumption, and antioxidant activity. GC/MS analysis allowed the identification of 28 compounds in the different essential oils. The principal identified component was limonene (86.7 %, 87.9 %, 88.2 %, 88.3 %, 85.4 % for HD, S-HD, US-HD, E-HD, and SFME, respectively), followed by β-pinene, sabinene, linalool and α-terpineol. The obtained essential oils were analyzed for their antioxidant activity using the 2,2-diphenyl-1-picrylhydrazyl radical scavenging method. Results indicated that essential oil extracted by SFME showed the highest antioxidant activity (IC₅₀ = 0.0175 mg/ml) and extraction yield (3.58 % ± 0.05) consuming lower energy (0.312 kW h^-1) in a shorter extraction time (30 min) comparing with the other tested techniques. Hence, the SFME would be an interesting green method for the recovery of essential oil from C. sinensis peels useful in agro-food, cosmetic, and pharmaceutical preparations as an alternative for undesirable chemical additives.

摘要

橙树（Citrus sinensis）是芸香科的一种水果灌木。柑桔皮的精油被广泛用于各种农业食品和药物制剂中，因此必须使用绿色提取方法对其进行回收。在这项研究中，我们比较了五种提取技术的效率（常规水蒸馏（HD），高清盐辅助提取（S-HD），高清超声辅助提取（US-HD），酶辅助提取）的效率。 HD（E-HD）和无溶剂微波提取（SFME）用于从柑橘中提取香精油皮。比较了香精油的化学成分，光学显微镜分析，总能量消耗和抗氧化活性。GC / MS分析可以鉴定不同精油中的28种化合物。鉴定出的主要成分是柠檬烯（HD，S-HD，US-HD，E-HD和SFME分别为86.7％，87.9％，88.2％，88.3％，85.4％），其次是β-pine烯，sa烯，芳樟醇和α-松油醇。使用2，2-二苯基-1-吡啶并肼基自由基清除法分析获得的精油的抗氧化活性。结果表明，SFME提取的香精油具有最高的抗氧化活性（IC ₅₀ = 0.0175 mg / ml），且提取收率（3.58％±0.05）消耗的能量较低（0.312 kW h ^-1）），与其他测试技术相比，提取时间更短（30分钟）。因此，SFME将是一种有趣的绿色方法，用于从中华绒螯蟹皮中回收精油，可用于农业食品，化妆品和药物制剂中，作为不良化学添加剂的替代品。