Isolation of essential oil from Lavandula angustifolia by using ultrasonic-microwave assisted method preceded by enzymolysis treatment, and assessment of its biological activities

This research study aimed to optimize innovative conditions for enhancing yield and quality of essential oil isolated from <em>Lavandula angustifolia</em> (La) based on rapid and innovative techniques. Ultrasonic-microwave assisted preceded by enzymolysis treatment was used to isolate essential oil (EO) of La. Response Surface Methodology was employed for the same purpose. The yield % of La essential oil (La.EO) obtained from combined enzymes treatment (cellulase and hemicellulase) was higher than that obtained by a single enzyme treatment. Chemical composition analysis of La.EO isolated was carried out using GC-MS. Morphological structure of La tissues was observed using SEM. The anti-free radical activity was assayed using DPPH and ABTS⁺ methods The isolation conditions consisted of the concentration of enzymes (12.5 mg) with a range of (5–20 mg), sonication time (52.5 min) with a range of (15–90 min) and microwave power (275W) with a range of (500–50W). The uses of coupling ultrasonic-microwave could be lead to forming of the acoustic cavitation and rupture of plant tissue. This facilitates the flow of liquid phase into the glandular trichomes in plant cells and enhances the absorption from the matrix of plant. Thus, enhances the efficiency of essential oil isolation from aromatic plant based on cavitation phenomenon. The results of the current work found that La.EO which isolated by using ultrasonic-microwave techniques under optimal conditions could be used as food additives in food industries to prevent the oxidation and bacterial spoilage.

本研究旨在基于快速创新技术，优化狭叶薰衣草（<em>Lavandula angustifolia</em>，简称La）精油的提取工艺条件，以提升其精油得率与品质。本研究采用酶解预处理结合超声-微波辅助法提取狭叶薰衣草精油（EO），并运用响应面法（Response Surface Methodology）开展工艺优化。采用纤维素酶与半纤维素酶组成的复合酶处理所得的狭叶薰衣草精油（La.EO）得率，高于单一酶解处理的得率。通过气相色谱-质谱联用仪（GC-MS）对提取得到的La.EO进行化学成分分析，借助扫描电子显微镜（SEM）观察La植物组织的微观形貌结构。采用DPPH与ABTS⁺法测定其抗氧化自由基活性。本次提取工艺的变量包括：酶投加量（12.5 mg，取值范围5–20 mg）、超声处理时间（52.5 min，取值范围15–90 min）以及微波功率（275W，取值范围500–50W）。超声-微波联用可引发声空化效应，破坏植物组织，促使液相渗透进入植物细胞的腺毛，强化从植物基质中的萃取效率，进而基于空化现象提升芳香植物精油的提取效能。本研究结果显示，在最优工艺条件下通过超声-微波技术提取的La.EO，可作为食品添加剂应用于食品工业，以防止油脂氧化与细菌腐败变质。