Decoction extraction procedure was implemented to regain phenolic compounds from C. citratus leaves. The extraction variables, solid/liquid ratio (2–5 g/100 mL), temperature (85–95 °C), and time (5–10 min) were assessed by central composite design for process optimization. Antioxidant activity (DPPH) and total polyphenol content (TPC) were monitored as responses. The TPC and DPPH were 71.98 ± 0.33 mg GAE/100 mL extract and 80.63 ± 0.49 mg TE/100mL extract respectively under optimal conditions (solid/liquid ratio = 5, temperature = 93.8 °C and time 11.3 min). The evaluation of phenolic compounds and volatile compounds of C. citratus extract at conditions for optimum extraction revealed that caffeic (20.81 ± 0.003 mg/100mL) and syringic acids (18.63 ± 7.390 mg/100mL) were the main phenolic compounds while citral and geraniol were the primary volatile compounds. The results achieved herein suits the potential use of C. citratus extract as natural source of antioxidant and aroma compounds that can be employed in different industrial sectors.

Practical application

Lemongrass obtained at the optimal extraction conditions is a good source of antioxidants and the extract has organic acids and a lemon scent due to the presence of citral. This extract can thereby be incorporated in the production of beverages which can help aromatize the beverage and also contribute in the addition of the antioxidant property of the beverage. It is also rich in organic acids, the main being propionic acid, which is known to have antimicrobial activity primarily against bacteria and mold. The lemongrass extract can therefore, extend the shelf life of the beverage they are incorporated in and also the citral present in lemongrass has antimicrobial properties.

中文翻译：

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柠檬香茅酚类化合物提取条件优化及提取物酚类和香气特征评价

实施煎剂提取程序以从C. citratus叶子中重新获得酚类化合物。提取变量、固/液比 (2–5 g/100 mL)、温度 (85–95 °C) 和时间 (5–10 分钟) 通过中央复合设计评估以进行工艺优化。监测抗氧化活性（DPPH）和总多酚含量（TPC）作为响应。在最佳条件下（固液比 = 5，温度 = 93.8 °C，时间 11.3 分钟），TPC 和 DPPH 分别为 71.98 ± 0.33 mg GAE/100 mL 提取物和 80.63 ± 0.49 mg TE/100 mL 提取物。柑桔酚类化合物和挥发性化合物的评价在最佳提取条件下的提取表明，咖啡酸（20.81 ± 0.003 mg/100mL）和丁香酸（18.63 ± 7.390 mg/100mL）是主要的酚类化合物，而柠檬醛和香叶醇是主要的挥发性化合物。本文取得的结果适合柠檬提取物作为可用于不同工业部门的抗氧化剂和芳香化合物的天然来源的潜在用途。

实际应用

在最佳提取条件下获得的柠檬草是抗氧化剂的良好来源，由于柠檬醛的存在，提取物具有有机酸和柠檬香味。因此，这种提取物可以掺入饮料的生产中，这可以帮助使饮料芳香化，也有助于增加饮料的抗氧化特性。它还富含有机酸，主要是丙酸，已知其主要对细菌和霉菌具有抗菌活性。因此，柠檬草提取物可以延长它们所掺入的饮料的保质期，而且柠檬草中存在的柠檬醛也具有抗菌特性。