In terms of the development and application of natural pigments, Japan is at the forefront of the world. As early as 1975, the use of natural pigments exceeded that of synthetic pigments.
Japan’s natural pigment market has exceeded 200 million yen, while synthetic pigments account for only one-tenth of the market, about 2 billion yen.
As of May 1995, there were 97 natural pigments approved for use in Japan. In the Japanese market, the annual demand for more than 200 tons is caramel pigment, annatto pigment, monascus pigment, gardenia yellow pigment, capsicum red pigment and curcumin, etc. 6 kinds of natural pigment products, of which the demand for caramel pigment The largest, with an annual consumption of 2,000 tons, accounting for about 40% of the total consumption of natural pigments.
China’s natural food coloring products have the largest production of sub-caramel coloring, with an annual output accounting for about 86% of natural food coloring, which is mainly used in the domestic brewing industry and beverage industry. Followed by red yeast red, sorghum red, gardenia yellow, red radish, sodium copper chlorophyll, carotene, cocoa shell color, turmeric, etc., mainly used in the preparation of wine, candy, cooked meat products, jelly, ice cream, artificial crab meat Waiting for food.
In the past, fruits and vegetables accounted for a large part of people’s daily food. This lifestyle is characterized by rich and healthy food. Later, people realized that many pigments that can bring bright colors to fruits and vegetables are actually very valuable nutrients.
Modern technology can also be used to develop more sophisticated products. There are many pigments in nature, some of which can be used as food colorings or as important nutrients. Many of these pigments have shades between yellow, orange and red.
Anthocyanins are a type of natural pigments, which are found in fruits and vegetables, making them appear red to blue. In industrial production, the common sources of most pigments are grapes, elderberries, raspberries and red cabbage (purple cabbage). Anthocyanins can not only be used as pigments, but also have many biological activities. Anthocyanins from different sources have different characteristics.
- Anthocyanins in grape skins can reduce the risk of heart disease;
- The anthocyanins of elderberry have resistance to influenza virus;
- The anthocyanin of raspberry has a good protective effect on eyesight.
Supercritical CO2 extraction of anthocyanins
The optimum process conditions for supercritical CO2 extraction of proanthocyanidins from grape seeds are: extraction pressure 30MPa, extraction temperature 55°C, material-to-liquid ratio 1:0.8, 60% ethanol as entrainer,
Another major category of natural pigments with nutritional properties are carotenoids.
Carotenoids are widely distributed in nature, generally showing yellow, orange and red.
Most fruits and vegetables contain a mixture of carotenoids. The extracts obtained from these fruits and vegetables are an important source of human essential nutrients. It has been confirmed that there are 600 different carotenoids in nature.
Beta-carotene is the most common carotenoid and has been widely used in food processing. Beta-carotene has been used in butter and margarine for many years. It not only provides these products with a yellow hue, but also Can provide vitamin A, this is mainly because β-carotene can be converted into vitamin A in the human body.
There are regulations in many countries that vitamin A must be added to margarine. Therefore, β-carotene becomes a source of vitamin A.
The most abundant mixed carotenoid in nature is the fruit of palm oil, which contains α, β and γ-carotene and lycopene. Many consumers have recognized that mixed carotenoids are beneficial to human health.
Natural carotene has become a very commonly used pigment, which can provide attractive yellow and orange colors to products.
In the past, carotene was mainly extracted with organic solvents such as n-hexane, which not only needed to consume a large amount of solvent, but also the product had to be removed to avoid toxicity caused by solvent residues.
Supercritical CO2 extraction can replace the traditional solvent method and effectively extract carotene.
Lutein is a yellow pigment from marigold.
- Antioxidant, it can fight against the degeneration of spots and protect the human body from damage caused by the action of singlet oxygen and free radicals;
- Prevent yellow retinopathy, alleviate senile vision loss; prevent blindness caused by muscular degeneration; prevent the occurrence and development of cancer and tumor;
- Prevent cardiovascular disease; enhance the body’s immunity, etc.
Organic solvent extraction of lutein
The high residual solvent content, low product purity, and peculiar smell cannot satisfy the market’s demand for high-quality lutein.
Supercritical CO2 fluid extraction of lutein
Marigold yellow pigment belongs to carotenoids and is easily oxidized and degraded. The supercritical fluid extraction technology can solve the above problems well, complete the extraction of natural pigments under mild conditions, and better preserve the biological activity of natural pigments.
The yield and color value of the pigment product extracted by supercritical CO2 are far greater than the index value of the pigment product extracted by the organic solvent method, and there is no residual organic solvent. The supercritical CO2 extraction method is a more effective way to extract the yellow pigment of marigold than the latter.
Lycopene is a bright red pigment, without the physiological activity of vitamin A, but has a strong antioxidant function. The content of ripe red plant fruits is higher, especially in tomatoes, carrots, watermelons, papaya and guava. It can be used as a pigment in food processing and is also a strong antioxidant, which can prevent many kinds of cancers. It is often used as a raw material for antioxidant health foods.
Extraction method of lycopene
The extraction process of lycopene mainly includes organic solvent extraction method, supercritical CO2 extraction method, HPLC method, enzymatic method, microbial fermentation method and direct crushing method.
Enzymatic extraction takes a long time, and the temperature must be strictly controlled during enzymatic extraction. In addition, when the enzyme is in an organic solvent, the enzyme activity is affected to a certain extent, resulting in a certain difference in the extraction rate of lycopene.
The organic solvent method extracts lycopene. When the organic solvent method extracts lycopene, the solvent loss is large, the time-consuming is long, the yield and purity are low, the selectivity is not high, and the safety risk is high.
Zea yellow pigment is a kind of natural food pigments with high utilization value such as carotenoid pigments and cryptoxanthin that can be extracted from corn husks or leftovers from corn starch production (corn crude protein).
It can be used for the coloring of food and cosmetics. Crypto yellow pigment can produce Va necessary for human body when it is decomposed. Zea yellow pigment can be widely used in medicine, food, packaging and other industries.
Supercritical CO2 Extraction of Corn Yellow Pigment
The conventional method for preparing corn yellow pigment is organic solvent extraction. Its disadvantage is that the product inevitably has residual solvent, which affects the quality of the product, and the production cycle is long.
Since supercritical CO2 fluid and corn yellow pigment are completely miscible, and supercritical CO2 fluid has good mass and heat transfer performance, non-toxic, non-combustible, cheap, and easy to obtain, supercritical CO2 fluid extraction technology is used for corn yellow pigment. The extraction is feasible.
The main sources of curcumin are the roots of ginger family turmeric (CurcumaaromaticaSalisb.), turmeric (C.longaL.) rhizomes, zedoaria (C.zedoaria (Berg.)Rosc.) rhizomes, and Acorus calamus (AcoruscalamusL.) rhizomes, etc. .
Curcumin also has antioxidant properties and has anti-inflammatory properties; curcumin is orange-yellow crystalline powder, slightly bitter in taste, and insoluble in water. It is mainly used in food production for intestinal products, canned food, and soy sauce products. Coloring.
Curcumin has the effects of lowering blood lipids, anti-tumor, anti-inflammatory, choleretic, and antioxidant. In addition, some scientists have found that curcumin can help treat drug-resistant tuberculosis.
Supercritical CO2 Extraction of curcumin
Curcumin is further divided into demethoxycurcumin, demethoxycurcumin and curcumin. The main extraction methods of curcumin can be divided into organic solvent extraction and water extraction. In the existing extraction method, curcumin is easily degraded during the process of extracting and recovering the solvent.
As a new type of green separation technology, supercritical carbon dioxide extraction technology can effectively extract high-purity curcumin from turmeric. The supercritical carbon dioxide extraction technology equipment is simple to operate, safe and reliable, without environmental pollution, and is an ideal separation method.
In the supercritical carbon dioxide extraction process, the extraction conditions are mild, and the inert environment of supercritical carbon dioxide protects the heat-sensitive substances during the extraction process and is not easy to decompose. The use of supercritical carbon dioxide extraction technology can effectively extract curcumin from the plant turmeric, and the extraction rate of its active ingredients is above 98%.