Propolis is a resin collected by bees from plant spores and tree trunks, mixed with bee mandibular gland secretions and beeswax to form an aromatic viscous gel-like isoform.
Its chemical composition is complex, containing phenols, acids, alcohols, esters, phenols, ethers, terpenes, enes, sterols and many trace elements.
In recent years, a large number of studies done by domestic and foreign scholars have shown that propolis has important physiological effects in the treatment of cardiovascular, diabetes, skin diseases, gastrointestinal diseases, anti-cancer, immune enhancement, antibacterial and anti-inflammatory, etc.
So it is used in modern medicine and health food research fields. Get more and more research and application.
Supercritical fluid technology has developed rapidly in recent decades.
In the pharmaceutical and food industries, supercritical fluid technology is mainly used for the extraction of active ingredients of Chinese herbal medicines, including volatile oils, alkaloids, glycosides, coumarins, and terpenes.
Because of its low critical temperature and low critical pressure (31.0℃, 7.39MPa), carbon dioxide has a strong affinity for medium and low molecular weight and non-polar natural products, and is colorless, odorless, non-toxic, non-flammable, and non-explosive , Low expansion, low viscosity, low surface tension, easy separation, low price, easy to produce high-purity gas and other characteristics, is the most widely used supercritical fluid.
The three methods of ethanol extraction, supercritical CO2 and supercritical CO2+ethanol (entrainer) extraction are used to extract and separate the crude propolis raw materials produced in Nileke County, Yili Prefecture, Xinjiang.
The yield of propolis extract is the highest among propolis. An important biologically active ingredient—total flavonoid content.
A preliminary comparative study of the three processes is carried out to provide a basic basis for the in-depth study of propolis refining processes.
Three extraction processes of supercritical CO2, supercritical CO2+ethanol and ethanol extraction were used to extract and separate crude propolis.
The three processes were compared and analyzed from the yield and the total flavonoid content in the extract.
The results showed that: in terms of yield, the ethanol extraction method was 54%, the supercritical CO2+ alcohol extraction method was 35.46%, and the supercritical CO2 method was 18%; in terms of the total flavonoid content, the supercritical CO2 + alcohol extraction method was 28.46%, ethanol The extraction method is 17.13%, and the supercritical CO2 method is 8.02%.
Extraction method of propolis
Propolis is a pure natural substance with both plant and animal properties. The source of propolis determines that its chemical composition mainly depends on the source tree species, and the source tree species is affected by ecological factors such as geographic location, climate, season, and vegetation.
Therefore, the production of propolis in different regions will inevitably lead to different chemical compositions of propolis, and different extraction processes will inevitably affect the quality of propolis.
Supercritical CO2 extraction method
The raw materials of propolis were pulverized after impurity removal and freezing. 45g of the pulverized propolis samples were accurately weighed and extracted under medium CO2 flow rate, extraction pressure 30MPa, extraction temperature 50oC, extraction time 90min, and two parallel experiments. The following processes are two experiments, and the average yield is taken.
Propolis raw materials → impurity removal → freezing, crushing → 95% ethanol solution soaking for 60 minutes → filtering → drying → alcohol extraction of propolis
Supercritical CO2+ethanol extract
Propolis raw material→freezing, crushing→supercritical CO2 extraction→separation of supercritical CO2 extract→CO2 raffinate (residue)→supercritical CO2+ethanol (entrainer) extraction→extract evaporating ethanol→supercritical CO2+ethanol extract
Determination of Propolis Yield
Weigh 45g of propolis and propolis CO2 extracts, and experiment under three different process conditions: supercritical extraction, ethanol extraction, and supercritical CO2+ethanol extraction, and accurately weigh the extracts to calculate the yield.
Experimental results of propolis supercritical method
According to the best industrial production process conditions of propolis by supercritical CO2 method, under laboratory conditions, the yield of propolis extracted by supercritical CO2 extraction method is 18% and the flavonoid content is 8.02%, which is different from that reported in the literature. It may be the raw material of propolis. The source is different.
Experimental results of ethanol extraction of propolis
According to the ratio of propolis sample to solvent ethanol is 1:3, parallel test twice, soaking, filtering, drying and weighing, the average yield of extract obtained by this method is 54%, and the flavonoid content of propolis is 17.13% . Compared with the supercritical CO2 method, the yield and flavonoid content are improved.
Propolis Supercritical CO2+Alcohol Extraction Test Results
Through the experimental study of different ratios of supercritical CO2 + ethanol entrainer, it is found that with the increase of the ratio of ethanol entrainer, the extraction yield obviously increases.
Under the best experimental conditions of this experiment, the yield is 35.46%, which is higher than The supercritical CO2 method has a higher yield, but it is lower than the ethanol extraction method. The flavonoid content is 28.46%, which is the highest among the three methods.
Through experimental research on three different extraction processes of crude propolis from Nilke County, Xinjiang, the results show that:
In terms of yield, traditional ethanol extraction has the highest yield, supercritical CO2+alcohol extraction is the second, and supercritical CO2 is the lowest;
The content of total flavonoids, the main bioactive components of propolis, is the highest in supercritical CO2 + alcohol extraction, followed by traditional ethanol extraction, and supercritical CO2 is the lowest.
If only the total flavonoid content is used as the quality comparison, the propolis obtained by the supercritical CO2 + alcohol extraction process has the best quality.
Process parameters of supercritical CO2 extraction of Propolis
Laboratory equipment: L-01 supercritical CO2 extraction machine
Pulverization degree:60 mesh
Extraction pressure: 30 MPa
Extraction temperature: 50°C
Separation pressure I: 14 MPa
Separation I temperature: 45°C
Separation pressure II: 8 MPa
Separation II temperature: 40°C
Extraction time: 90 min