Capsaicin is a high carotenoid system of orange-red natural food pigment extracted from capsicum. The pigment belongs to terpene pigments, and the product is in the form of viscous liquid or powder after drying. It has good thermal stability, acid and alkali resistance, light resistance and emulsification and dispersion. Capsaicin contains carotene, beta carotene and a variety of vitamins, and has rich nutritional value. Therefore, capsaicin extract can be widely used in food, medicine and cosmetics and other industrial products color.
Alkali water solution treatment -- solvent extraction -- steam distillation
Over the years, researchers have conducted comprehensive experiments on the extraction methods of capsaicin at home and abroad, and it is believed that the capsaicin with good color, purity and stability can be produced by alkali water solution treatment, solvent extraction and steam distillation.
1. Technological process: Pepper → extraction → distillation → chili oil resin → hydrolysis → filtration → solid → immersion → decompression filtration → extract → decompression distillation → pigment → steam distillation → concentrated and refined pigment → drying → powdered capsaicin
2. Extraction method
(1) extract chilli oil resin. Put ripe pepper fruit drying, after extraction tank, at room temperature, continuous extraction with organic solvent, from the organic solvent extract of distillation, with lower aliphatic alcohols solvent extraction oleoresin capsicum, adding amounts to about 10 times of the chilli oil resin, the temperature of room temperature to the boiling point of alcohol, stirring time 1 to 10 hours. After that, the capsaicin phase was separated by decanting or liquid-liquid centrifugation. Then, under atmospheric pressure or vacuum state, steam distillation, distillation of residual alcohol, to get the resin containing capsaicin.
(2) Alkaline solution treatment. The resin containing capsaicin was distilled and treated with alkali water solution. The concentration of alkali water solution is about 45%, the added amount is equivalent to 3-5 times of the weight of resin after distillation, the temperature is 80℃, and the stirring time is 3-10 hours. Then the pH value was adjusted between 4-6.5 to convert the fatty acids in the resin containing capsaicin from water-soluble alkali salt to free fatty acids. PH regulator is a common inorganic or organic acid. After regulating acid, add precipitant slowly to transform free fatty acid into insoluble or insoluble salt and precipitate. The precipitators are barium hydroxide, magnesium hydroxide, calcium hydroxide, etc., and the dosage is 2-8 times of the weight of chili oleate after acid adjustment. After precipitation, the soap-alkali solids are obtained by centrifugation or filtration.
(3) extraction. The saponin-like solids were placed in the extraction tank, and organic solvents were added for continuous extraction, including acetone, butanone, methyl acetate, methanol, ethanol, propanol, pentane, benzene, toluene, diethyl ether and other petroleum ethers. The addition amount of organic solvent is equivalent to 1-15 times of solid weight, the temperature is controlled at room temperature, and the extraction time is about 1-15 hours depending on the choice of solvent.
(4) distillation. The extract was often distilled under pressure or vacuum, and the organic solvent was removed to obtain a color value of 300,000-650,000 capsaicin. If the pigment still has peculiar smell of chilli, decompress the pigment at about 26.7kPa and steam distillation for 4 hours to remove the peculiar smell. After filtering out the water, it is dried in a vacuum dryer to get concentrated and refined pigment. It can also be dried at low temperatures to produce powdered capsaicin.
CO2 supercritical extraction
In addition to the above methods, the world's current supercritical extraction method. Compared with the traditional method, the CO2 supercritical extraction method avoids the use of organic solvent and eliminates the operation steps such as distillation. It is a very promising extraction method.
Extraction process: chili powder → extraction tank → separation tank → coarse pigment → extraction tank → separation tank → pigment
The specific operation is as follows: the pepper is dried and crushed and placed in the extraction tank. The flow rate is 5L/min and the pressure is 12mPa. The temperature of the extraction tank is 40℃. The extract was then put into the extraction tank, with a flow rate of 5L/min and a pressure of 45mPa of CO2. The tank temperature was 40℃ and the extraction time was 40min. Then, the extract was put into the separation tank and decompressed to atmospheric pressure to obtain capsaicin with no spicy taste.
Separation of capsaicin
Capsaicin can take on a variety of hues depending on the concentration. In recent years, capsaicin has been directly separated into black, yellow, red, orange and other single pigments by column chromatography. These single pigments have good thermal stability. After heating at 100℃ for several hours, the survival rate of pigments is around 95%, and they have good light resistance.
The concentration of capsaicin was added into the glass column with silica gel, and the ratio of silica gel and capsaicin was 5:1. Then it was eluted with n-hexane, which was distilled in the eluent. Then, 5% isopropyl ether and 95% n-hexane were eluted, and the yellow pigment was obtained after distilling solvent in the eluent. Then, 25% isopropyl ether and 75% n-hexane were eluted. The red pigment was obtained after distilling the solvent in the eluent. Finally, the orange pigment was eluted with acetone after distilling the acetone.