Gingerol is a mixture of gingerol, gingerol, parazingerone, gingerone, ginger dione, gingerol and other spicy substances.
It is not only the main flavoring substance of ginger’s characteristic flavor, but also the main functional factor of ginger’s multiple pharmacological effects. It is widely used in condiments, health products, medicines and cosmetics and has good application prospects. Next, let us understand its extraction method!
Method of extracting gingerol
Gingerol is soluble in organic solvents such as ether, acetone, ethanol, methanol, etc. The commonly used solvent extraction methods are divided into cold extraction and hot extraction.
When the solvent is added to the raw material, it enters the cell due to the diffusion and penetration of the solvent, dissolving soluble substances. The resulting difference in internal and external concentration causes the concentrated solution in the cell to continuously diffuse outwards, and the solvent continues to enter the raw tissue cells, back and forth repeatedly, until the concentration inside and outside the cell reaches a dynamic equilibrium, filter out the saturated solution, and add new solvent to Most of the required ingredients dissolve.
Ethanol is cheap and non-toxic. It is the preferred extraction solvent for gingerol. Ethanol is used to extract gingerol, the extract is distilled under reduced pressure, and the content of gingerol is determined by ultraviolet spectrophotometry.
The results showed that ginger powder 60 mesh, ethanol volume fraction 75%, solid-to-liquid ratio 1:9 (g/mL), extracted at 50 ℃ for 90 minutes, extraction once, the content of gingerol in ginger oleoresin reached 1.59% .
The solvent extraction method has the advantages of simple operation, complete extraction, low extraction cost, etc., and is currently a widely used extraction method in industrial production;
The product has a high viscosity and contains more impurities such as resin and fatty oil, which increases the difficulty of the later separation and purification. Therefore, the purity of the product is not high and there is a tendency to be gradually eliminated.
Supercritical CO2 extraction method
Supercritical CO2 fluid is a special kind of fluid, which has the solubility of liquid and the diffusion coefficient of gas, and its properties are very sensitive to pressure and temperature.
The supercritical CO2 extraction process is to contact the supercritical CO2 fluid with the substance to be separated under the supercritical state, so that it can selectively extract the components of polarity, boiling point and molecular weight in sequence.
Finally, the supercritical CO2 fluid is turned into an ordinary gas by means of decompression and temperature rise, and the extract is basically precipitated, so as to achieve the purpose of separation and purification.
Supercritical extraction can be carried out at room temperature (35-40°C), effectively preventing the oxidation and dissipation of heat-sensitive substances, and can protect the effective components of the extract.
Someone compared the extraction with ethanol, acetone and supercritical CO2 extraction of gingerol. The results showed that the yield of gingerol by supercritical CO2 extraction was 0.7155%, which was significantly higher than that of ethanol and acetone.
The supercritical CO2 extraction method is a clean extraction method with simple process and fast extraction speed. The whole process does not use organic solvents, ensuring the pure naturalness of the extract. And CO2 is cheap and non-toxic.
However, when this method is adopted, the extraction pressure is high and the energy consumption is large.
Ultrasonic extraction is an extraction method that uses ultrasonic waves to increase the frequency and speed of the movement of material molecules, increase the penetration of solvents, increase the dissolution rate and number of dissolution of drugs, and shorten the extraction time.
Ultrasound is to generate cavitation between the solvent and the sample, make bubbles form in the solution, burst and compress, so as to disperse the solid sample, increase the contact area between the sample and the extraction solvent, and improve the transfer of the target product from the solid phase to the liquid phase. The mass transfer rate.
The extraction rate of gingerol in ultrasonic-assisted extraction is higher than the traditional solvent extraction method. The general extraction step is to dry and crush the ginger, add ethanol and ultrasonic treatment, and finally concentrate and crystallize to obtain a solid product, or directly determine the content after centrifugation .
Using ethanol as the extractant, the technological conditions of ultrasonic extraction of gingerol were studied: ethanol volume fraction 60%, ultrasonic treatment 15min, feed liquid: 12.5 (g/mL), ginger powder passed through a 60 mesh sieve, and extracted 3 times in parallel. The average extraction rate can reach up to 3.03%.
The microwave radiation process is that high-frequency electromagnetic waves penetrate the extraction medium and reach the inside of the material. Due to the absorption of microwave energy, the cell rapidly heats up, the cell wall pressure increases, swells and ruptures, and the effective components in the cell flow out and dissolve into the extractant. After further filtering and After separation, the extracted substance is obtained.
In addition, the electromagnetic field generated by the microwave accelerates the diffusion rate of the extracted components to the interface of the extractant, which increases the extraction rate by several times.
The process of microwave extraction of gingerol is similar to ultrasonic extraction, but the time is shorter, generally only a few minutes. Gingerol is extracted from ginger by microwave extraction technology.
The results showed that the particle size was 80 meshes, the microwave power was 250W, the solid-liquid ratio was 1:12.5 (g/mL), and the extraction time was 180s. Under these conditions, the yield of gingerol was 0.776%.
The extraction process parameters of gingerol were optimized through orthogonal experiments, and the best process conditions were obtained: 66% ethanol solvent, 1:16 ratio of material to liquid (g/mL), microwave power 300W, and microwave co-processing for 70s. Under these conditions, ginger The extraction rate of capsaicin reached 1.76%.
Microwave-assisted extraction technology has the advantages of short extraction time, high yield, low energy consumption, and less solvent consumption, making it widely used in various fields.
However, microwave heating is rapid and difficult to control, resulting in a certain degree of decomposition and deactivation of gingerol, which affects product quality. How to better use it in industrial production needs to be improved.