Research progress on the extraction and application of capsicum red pigment
Capsanthin is a tetraterpenoid orange-red pigment present in mature red pepper fruits. It is mainly composed of capsanthin (C40H56O3), capsorubin (C40H56O4) and yellow pigment. It has bright color and high color value. It has strong coloring power and good color retention. Studies have proven that capsicum red pigment also has the effect of regulating body fat metabolism, immunity, anti-radiation and reducing the incidence of certain types of cardiovascular diseases.
Capsicum red pigment is widely used as a coloring agent and is listed as a Class A pigment by the Food and Agriculture Organization of the United Nations (FAO) and the World Health Organization (WHO). According to my country’s GB 2760-2014 “Standards for the Use of Food Additives”, capsicum red pigment can be used in food, sauces, ice cream, ice cream, biscuits, cooked meat and other products.
Capsicum red pigment extraction
Appropriate extraction methods can reduce the content of orange and yellow substances and non-pigment components in capsicum pigments, thereby increasing the proportion of capsanthin and capsorubin and increasing the color value. Judging from the current extraction methods of capsicum red pigment, the common ones include solvent extraction, ultrasonic extraction, microwave-assisted extraction and supercritical fluid extraction.
Solvent extraction method
Solvent extraction is a commonly used method for extracting capsanthin, which takes advantage of the fact that capsanthin is soluble in organic solvents. The specific extraction process is to beat mature dried chili peppers into powder, then mix them with organic solvents such as ethanol, acetone and other substances to prepare chili oleoresin, and then go through a series of procedures, such as distillation, separation, etc., to finally obtain capsicum red pigment .
The significant advantage of the solvent extraction method is that it is low cost and does not require expensive and sophisticated equipment to implement; the disadvantage is that the purity of the extracted capsanthin is not enough and there are many organic reagent residues. At present, most domestic and foreign manufacturers producing capsicum red pigment use this method to extract, but it has also shown a trend of being gradually eliminated.
Ultrasonic extraction method
The principle of the ultrasonic extraction method is to use ultrasonic waves to crush the peppers more finely, so that the components in the peppers can be better integrated in the extraction solvent, and finally obtain capsicum red pigment with higher purity. Ultrasonic extraction method has similarities with solvent extraction method, but it is faster, more efficient and lower cost than solvent extraction method. The most important thing is that it is natural and environmentally friendly, so it is more popular.
Microwave-assisted extraction
Microwave-assisted extraction, also known as microwave extraction, is a new technology formed by combining microwave and traditional solvent extraction methods. Microwave-assisted extraction of capsicum red pigment is low-carbon, environmentally friendly, and has high extraction efficiency.
supercritical fluid extraction method
The supercritical fluid extraction method uses pressure control and temperature control to enhance the dissolving effect of CO2 on peppers, and finally selectively extracts capsicum red pigment. This method can be implemented at room temperature, and there is no solvent residue in this method, and the purity of the extracted capsanthin is high. It is currently an ideal extraction method for capsicum red pigment.
Factors affecting the stability of capsicum red pigment
Capsicum red pigment is protected by cells in the pepper fruit. At this time, it is highly resistant to light and heat. However, after extraction, light, heat, oxygen, pH and metal ions will degrade it. After degradation, the olefin bond will be converted into a single unit. The bond may be broken, causing the conjugated structure to be destroyed, and the reason for fading is that photocatalytic oxidation and hydrolysis rearrangement reactions occur internally.
Effect of light and heat on the stability of capsicum red pigment
Natural carotenoids mainly exist in the all-trans form in nature. Temperatures of 80°C and below have little effect on the stability of capsicum red pigment. High temperature and heating time are the main factors affecting the pigment loss rate. Under light and heat conditions, the pigment molecules undergo an energy level transition and transform into a cis structure. The electromagnetic spectrum blue shifts by 2 to 10 nm, accelerating the oxidation and breakage of the pigment molecular chain, causing the spectrum to move to the ultraviolet region, causing the capsicum red pigment to decompose and lose color. Blue light and ultraviolet light irradiation in the light cause a series of oxidation, rearrangement, isomerization and other degradation reactions, which increase the color loss rate of capsicum red pigment, especially at positions 7 to 8, 9 to 10 and 8 to 9. Carbon-carbon bonds break, ultimately causing the pigment to fade.
Effect of oxygen on the stability of capsicum red pigment
Oxidants will cause the loss of capsicum red color. Adding peroxidase (POD) and catalase (CAT) can reduce the damage of capsicum red color by reactive oxygen species. The addition of antioxidants such as VE, tea polyphenols, and ascorbyl palmitate can protect the red color of capsicum. Under the same oxygen content, the color retention rate of capsicum red pigment with 1% carnosic acid is the highest.
Effect of irradiation on the stability of capsicum red pigment
Research has found that as the amount of irradiation increases, the discoloration loss of pigments intensifies. The esterified structure has stronger radiation resistance than the monomer, and the stability of red pigments is higher than that of yellow pigments. In order to maintain good color after irradiation, The irradiation dose needs to be controlled below 4kGy. 70% to 80% of the pigments in peppers mainly exist in the form of esters. The yellow series mainly combines unsaturated fatty acids, and the red series combines saturated fatty acids. The difference in stability of red and yellow capsicum pigments may be related to their special molecular structures and fatty acids. The composition, the proportion of different carotenoid combinations and the content of non-carotenoid substances are related.
Effect of ultrasound on the stability of capsicum red pigment
Ultrasound, as an auxiliary method for extracting capsanthin from peppers, allows the peppers to fully contact and fuse with the extraction liquid, thereby improving the solvent extraction efficiency. However, ultrasound itself has a degradation effect on the carotenoids in capsicum. The hydroxyl radicals generated by ultrasound can cause the degradation and structural changes of zeaxanthin, resulting in the degradation of zeaxanthin and the blue shift of its spectrum. The impact of the ultrasonic process on β-carotene has two aspects: ① The thermal effect of rising temperature, ② The ultrasonic cavitation effect leads to pigment degradation.
Effects of pH and metal ions on the stability of capsicum red pigment
Research has found that capsanthin has a wide range of acid and alkali tolerance and can maintain a stable chemical structure within the pH range of 4 to 10. The impact of common metal ions in the sauce system on the color and value of capsanthin is less than 6%. . Capsicum red pigment is prepared into a microemulsion, which has good stability under acidic conditions. Under the action of Cu2+, Fe3+, and Fe2+ ions, the color tone of capsicum red pigment is greatly damaged. Different types and concentrations of metal ions were added to a single pigment acetone solution. As the concentration of metal ions increased and the action time increased, the absorbance of capsanthin decreased to varying degrees. Therefore, in the actual application process, it is necessary to strictly control the concentration of metal ions in the application system, or add anti-interference agents to prevent damage to capsicum red pigment.
Application of capsicum red pigment
Food industry field
Capsicum red pigment has stable properties, good coloring effect, and no toxic or side effects. It can supplement the body’s carotenoid compounds. Therefore, the food industry production field has a strong dependence on capsicum red pigment. Capsicum red pigment is mainly used to improve food color and enhance appetite. It can be used in daily edible products such as meat products, candies, beverages, sauces, and baked goods.
Adding capsicum red pigment to chicken chops and minced pork to adjust their color and brightness can enhance consumers’ visual experience and improve the sensory quality of the product. Adding capsicum red pigment to bionic foods such as crab sticks and shrimp balls can simulate the color of real marine foods. However, due to differences in the characteristics of product matrices, and based on factors such as storage time, temperature, etc., multiple stability evaluations need to be conducted on products containing capsicum red pigment to ensure constant product quality during the shelf life.
Animal feed field
The production of animal feed is also inseparable from capsicum red pigment. There are two main reasons why capsicum red pigment can be used in animal feed: First, capsicum red pigment is a purely natural pigment, which is safe and stable in coloring. Second, animals cannot synthesize pigments themselves, so the feed becomes a supplementary pigment for them. The necessary way, capsicum red pigment can improve the skin coloration of pigs, cattle, sheep, fish, shrimps, etc., help synthesize pigments, enhance the health of animals, and improve the appearance. Therefore, capsicum red pigment is very popular in animal feed.
Research shows that when 100 mg/kg capsicum red pigment is added to the feed of goldfish and koi, after feeding for a certain period of time, the a* (redness) of the body surface is significantly increased, and the MDA (malondialdehyde) in the serum and liver is lower than The results showed that capsicum red pigment can effectively enhance the red color of fish body surface and improve the body’s antioxidant capacity.
Medical field
Capsicum red pigment is widely used in the medical field. Because capsanthin has a stable coloring effect and a certain drying effect, it is often used in drug coatings and capsule particles. Especially for children’s medicine, the bright capsicum red pigment can reduce children’s fear of medicine and increase children’s interest in taking it. In addition, in recent years, it has been discovered that carotenoids in capsanthin have the effect of treating arteriosclerosis. This discovery has improved the application value of capsicum in the medical field.
Cosmetics field
As a natural pigment, capsicum red pigment has bright colors and can be added to lipstick, blush, eye shadow and other products. It can replace synthetic pigments to make the products safer.However, capsicum red pigment, as a fat-soluble pigment, has many factors that affect its stability. When adding it, you need to consider its form of use and the impact of ingredients on its color.
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