Extraction methods in the food industry
Extracting nutrients from raw materials of agricultural and sideline products and processing them into different products is an important part of food production. The advanced extraction technology is a key factor in determining food quality.
Commonly used extraction techniques include solvent extraction, pressing, ultrasonic assisted extraction, microwave extraction, enzyme extraction, membrane separation technology, supercritical fluid extraction, etc.
Supercritical fluid extraction
Supercritical fluid extraction is a new separation and extraction technology, which is more and more widely used in the food industry.
Supercritical fluid extraction technology uses supercritical gas as an extractant to extract, separate and purify effective ingredients from liquid or solid materials.
Compared with the traditional solvent extraction method, its advantage is that there is no solvent consumption and residue, avoiding the thermal degradation of the extract at high temperature, and can remove the pesticides and pesticides in the raw materials, protect the biologically active substances, and use the gas as the extraction solvent. Toxic, easy to recycle, and will not cause environmental pollution.
The gases that can be used as extractants include carbon dioxide, ethylene, propylene, ethane, methanol, ethanol, etc. CO2 is the most widely used and studied gas.
Application of Supercritical Fluid Extraction Technology in Food Industry
Use supercritical extraction technology to decaffeinate coffee
The use of supercritical fluid extraction technology can selectively remove some substances in food. The most widely used application is the production of decaffeinated coffee. This technology is currently very mature and widely used.
As early as 1955, China also studied the supercritical fluid extraction method to remove caffeine from Yunnan small-grain coffee beans, and compared the caffeine content in coffee beans treated with SFE and those without SFE, and determined that SFE technology has an effect on coffee. Due to the removal effect, it has been found that under the appropriate pressure and extraction temperature, most of the caffeine in the small coffee can be removed by using the SFE technology, and the extraction rate can reach more than 75%.
Using supercritical fluid technology to extract the effective components in hops
Take the active ingredients in hops
The quality of hops directly affects the quality and taste of beer. The main ingredients in hops are α-acids, hop essential oils, flavonoids, etc. These effective ingredients will decrease and be oxidized with the extension of storage time, making hops The utilization rate of the effective ingredients in the product is significantly reduced.
Therefore, it is very necessary to extract the effective ingredients from hops to facilitate storage, reduce transportation costs, and improve the utilization of effective ingredients.
Traditional extraction method
The traditional method is to use organic solvents for extraction. The disadvantages are poor product quality and the presence of chemical solvent residues.
Supercritical CO2 fluid method
The use of supercritical fluid technology to extract effective ingredients from hops can improve this situation.
The effects of different temperatures, different pressures, different concentrations of ethanol (modifier) and material-to-liquid ratio on the extraction rate of flavonoids in hops were studied. The results showed that the extraction rate of flavonoids in hops was the highest at 50°C, 25MPa, material-to-liquid ratio (50+50), and ethanol concentration of 80%.
Supercritical fluid technology to extract flavors and fragrances
Traditional extraction method VS supercritical fluid extraction method
Traditional flavor extraction methods include steam distillation, rectification, solvent extraction, leaching, pressing and other methods. However, during the extraction process, problems such as thermal decomposition, solvent residue, and volatilization loss of some aromatic substances are prone to occur.
The supercritical fluid extraction technology can solve these problems and obtain high-quality flavors and fragrances that can maintain natural color, fragrance and taste.
At present, this method has been used to extract high-quality essential oils from lilacs, roses and other fragrant flower materials, and from almonds, star anise, peppermint and other edible spices.
Supercritical fluid technology to extract natural pigments
Natural pigments are one of the most widely used food additives. They are not only used in foods such as candies, beverages, cakes, etc., but also in the production of medical and health care products. They have broad prospects and markets. The use of advanced separation technology to improve the quality of natural pigment products plays an important role in promoting the development of the food industry.
Supercritical CO2 extraction of natural pigments
Compared with the traditional extraction process, the supercritical CO2 extraction technology has shown obvious advantages in the extraction method of natural pigments.
At present, it has been successfully applied in the extraction and purification process of natural pigments, mainly concentrated in isoprene derivatives (such as carotene, lutein, capsanthin, lycopene, zeaxanthin, etc.), polyphenols Types (such as anthocyanins, cocoa pigments, etc.), tetrapyrrole colors (such as chlorophyll), ketones (such as monascus pigment, curcumin, etc.), quinones (such as shikonin) and other major types of pigments.
Supercritical fluid technology to extract vegetable seed oil
Vegetable seed oils such as linseed oil, wolfberry oil, sea buckthorn seed oil, pumpkin seed oil and grape seed oil contain a large amount of unsaturated fatty acids and biologically active ingredients, etc., which have good health care effects and are important for functional foods. One of the raw materials has attracted extensive research and attention.
How to efficiently separate and extract vegetable seed oil from the raw materials has also become the focus of attention. Supercritical fluid extraction technology once again shows unparalleled advantages in this respect. Supercritical CO2 extraction technology can effectively avoid solvent residues and remove pollutants such as pesticide residues in raw materials. It is a green and clean separation technology.
There is an article on the feasibility of using supercritical fluid extraction technology to extract grape seed oil from waste grape seeds on our website, explaining the effect of extraction temperature, extraction pressure, CO2 dosage and different raw materials on the yield of grape seed oil. At the same time, published more application articles of supercritical fluid extraction in soybean oil, raisin oil, rice bran oil, fish oil and γ-linoleic acid.