Study on Enzymatic Extraction Process and Antioxidant Activity of Essential Oil from Duxiang
Ledum palustre L., also known as trumpet flower or tripping silk, is an evergreen upright shrub in the Rhododendron family. It is mainly distributed in Northeast China (Greater and Lesser Khingan Mountains and Changbai Mountain), Korea, Japan, Siberia, North America, Europe and other places. Du Xiang has a strong aromatic odor and can be used for medicinal purposes and for extracting essential oils. The essential oil of Elaeagnus microphylla is one of its active ingredients. The branches, leaves, flowers and fruits of Elaeagnus microphylla can all extract aromatic essence oil, of which the oil yield rate of flowers and fruits is high. It has the functions of sterilization, anti-inflammatory, antitussive and expectorant, promoting transdermal absorption, acaricidal, insect repellent, antioxidant, anti radiation, liver protection and detoxification. Chinese medicine believes that Elaeagnus microphylla has the effects of resolving phlegm, relieving cough and relieving asthma. The efficacy of the essential oil of Duxiang has been used in daily life, medical treatment, spice production and other fields. The components of the essential oil of Duxiang are affected by growth conditions and regions, and are easy to change when extracted. The essential oil of Duxiang can be analyzed by GC-MS. Its chemical components are mainly terpenes and their derivatives.
At present, the main methods of extracting essential oil from Duxiang include extraction, supercritical CO2 extraction, microwave extraction, ultrasonic extraction, extraction and steam distillation. Compared with other methods, steam distillation has the advantages of easy operation, simple method, and low cost. However, its extraction rate is low, time-consuming, and insufficient. In this study, enzymatic hydrolysis was used to destroy the cell wall of Du Xiang cells, greatly improving its extraction rate and fully extracting essential oil components.
This study plans to extract essential oil of Duxiang by enzyme assisted steam distillation. The research content is to optimize the production process by single factor and response surface methodology under the condition of enzyme assisted extraction, so as to provide technical support for large-scale production of essential oil of Duxiang; The essential oil of Duxiang was analyzed by high performance gas chromatography-mass spectrometry (GC-MS); In order to study its antioxidant activity, the scavenging capacity of essential oil of Duxiang on DPPH free radical, ABTS free radical and hydroxyl free radical was determined.

 

 

This paper compared the effects of different enzyme pretreatment on the extraction of essential oil from Duxiang powder, and determined to use pectinase for enzyme treatment and enzyme assisted steam distillation to extract essential oil from Duxiang powder. Through single factor and response surface experiments, the optimal extraction conditions of enzyme assisted steam distillation were determined as follows: pH of enzyme was 5.5, the ratio of material to liquid was 1:20, the enzymolysis time was 4h, the enzymolysis temperature was 55 ℃, the concentration of enzyme was 1.5%, and the extraction time was 1.5h. Under this condition, the extraction rate of essential oil of Duxiang was 1.71%, and the extraction rate of essential oil of Duxiang was 1.02% by conventional steam distillation. The extraction rate of essential oil of Duxiang was increased by 67.65%, indicating the efficiency of enzyme assisted extraction, which provides a more green and efficient method for the large-scale production of essential oil of Duxiang.
The main chemical components of essential oil of Duxiang were determined and analyzed by GC-MS. The difference between enzymatic extraction and steam distillation was compared. There are 44 kinds of chemical components in the essential oil extracted by enzyme assisted extraction, and 39 kinds of chemical components in the essential oil extracted by steam distillation; Enzymatic extraction of essential oil from Duxiang has a richer variety of components, indicating that the essential oil can be better released under the assistance of enzymes. The results showed that the extraction method of enzyme assisted steam distillation could better obtain the effective components of essential oil of Duxiang.
In the antioxidant experiment, the enzyme assisted extraction of essential oil of Duxiang has a stronger scavenging capacity for DPPH free radicals, ABTS free radicals and hydroxyl free radicals than the steam distillation extraction of essential oil of Duxiang, which has obvious antioxidant activity and a good dose effect relationship.