According to its source and nature, food coloring is divided into edible natural pigments and edible synthetic pigments. The edible natural pigments are mainly pigments extracted from animal and plant tissues, including microbial pigments. In addition to the poisonous cane that can not be used in the edible natural pigment, it is generally harmless to the human body and safer, but the natural pigment is relatively expensive and the stability is slightly poor.

Edible synthetic pigments, also known as synthetic dyes, are artificial synthetic pigments. The artificial synthetic pigments are mostly made of coal tar as raw materials, the cost is low, the color is bright, the tinting strength is strong, and the color tone is diverse, but most of them have certain harm to human health and have no nutritional value, therefore, it is generally not suitable for processing in meat products. use.

The development and application of natural pigments is a trend in the world today. The natural pigments commonly used in meat products are caramel color, red yeast red, sorghum red, nitroso hemoglobin pigment, lycopene and the like.

1

Caramel color

Caramel color, also known as sauce color, caramel color, is a kind of starch syrup, sucrose, xylose mother liquor, etc., which is made of ammonia method, ammonium sulfite method and common method, and has a special sweet aroma and a pleasant bitterness. A powdery or liquid gelatinous substance that is soluble in water and has a vivid reddish-brown color. It consists of more than one hundred compounds. Caramel color can be divided into four categories according to the catalyst used in the process, namely ordinary caramel, caustic sulfite caramel, ammonia caramel, ammonium sulfite caramel. Caramel color is easily soluble in water and insoluble in common organic solvents and oils. The aqueous solution is reddish brown, transparent and turbid or precipitated. Stable to light and heat. It has colloidal properties and has an isoelectric point. The pH varies depending on the method of manufacture, usually from 3 to 4.5. Caramel pigments have colloidal properties, each with a small charge, which can be a positive charge or a negative charge, depending on the method of production and the pH of the food used. Must pay attention to the selection, otherwise it will have an effect on the effect of use. For example, the acid-resistant colloidal pigment used in cola beverages should be negatively charged, the isoelectric point is less than 1.5, and the positively charged in soy sauce and rice wine. Caramel coloring. From a microbiological point of view, caramel color is a very stable product. Since bacteria cannot survive in caramel color, the shelf life is set at 12 months. The pH of the caramel color is an important indicator in the application, and the pH of the caramel varies from species to species. If the pH of the caramel is > 5.0, the microorganisms are easily contaminated, and if the pH is <2.5, the resin is formed in a short time, and the lower the pH, the faster the change. Acid-resistant caramel, which has a pH of 2.8-3.3 and an average of 2.9-3.0, is mostly used in the beverage industry. The addition of caramel at 4.5 to 5.0 is also added to beer and soy sauce. Since the pH of the medium is not changed and the chargeability of the solution is consistent, the solubility increases. The pH of the caramel is generally determined by the processing of the raw materials and can be adjusted according to different needs.

Caramel color is widely used in meat products, such as canned meat and stew, as well as simulated meat from vegetable protein. Carbohydrates with positive and negative charges can be used in meat products. The red index problem should be considered when selecting. The application of caramel color in meat products mainly has the effects of flavoring, anti-oxidation and masking of odor.

2

Monascus Red

Monascus pigment is derived from microorganisms and is a natural pigment produced by fermentation of Monascus. Monascus pigment consists of six basic pigments such as erythema, monascus, red yeast, monascus, melamine, and monascus. Monascus pigment is red or dark red liquid, powder paste, slightly odorous, melting point about 60 ° C, soluble in ethanol, ether, glacial acetic acid, insoluble in water, glycerin, it can be considered stable to pH, heat resistance Strong (100 ° C or more), light resistance, almost independent of the oxidant and reducing agent, good dyeability to protein, once colored, not washed after washing.

Monascus pigment has good coloring performance, can impart unique color and flavor to meat products, and red yeast pigment has strong antibacterial effect. The antibacterial test results of Japanese Endo's cultivar showed that Monascus can produce active substances with bactericidal or bacteriostatic action during the growth and metabolism process, and the test proves that some of the antibacterial active substances are pigment components. As a natural pigment, Monascus pigment is used in meat products and can partially replace the coloring agent nitrite in meat products. The German Meat Research Center has studied and discussed this. After adding red yeast to the cured products, the amount of nitrite can be reduced by 60%, while its sensory properties and storability are not affected. If the nitrite dosage is further reduced, the product flavor is slightly different from the original product. A product that adds monascus pigment and reduces the amount of nitrite by 60%, not only has uniform color, but also has much better color stability than the original product. Li Kaixiong and others studied the effect of the addition of red yeast rice pigment on the color of ham meat. The study found that the use of red yeast rice pigment can not only improve the redness value of meat products, but also greatly reduce the dosage of NaNO2. The meat products are safer and the color is more satisfactory. The study found that the application effect of monascus red pigment in the replacement of sodium nitrite in bacon, the results show that red yeast red pigment can be added to the bacon in the form of injection, the amount added is 0.001% of the meat weight. At the time of injection, it is required to increase the injection point, reduce the injection amount per point, and make the injection uniform. From the perspective of color, moisture content and texture, it can reach a level similar to sodium nitrite. The attempt of bacon non-nitrogen coloring agent is basically feasible.

3

Gao Xiaohong

The sorghum red pigment is obtained by extracting black purple sorghum shell, and its main coloring matter is apigenin. Sorghum red pigment is dark red liquid, paste or powder; soluble in water, ethanol, insoluble in oil; aqueous solution is red when acidic, purple when alkaline, very stable to light and heat, but susceptible to metal ions The effect, especially in the case of iron ions browning, the addition of traces of sodium pyrophosphate can inhibit the influence of metal ions.

Sorghum red pigment has good coloring properties for protein, the color is close to the natural color of meat, has a sense of realism, and has a good shelf life and color retention performance, and is widely used in the processing of meat products. According to the national standard GB2760, the maximum use of sorghum red pigment in cooked meat is 0.4g/kg. In ham, sausage and other enema products, it can be added in the amount of 0.3~0.5g/kg, which can achieve the ideal coloring effect. The study found that sorghum red color is used as sausage and ham coloring agent. The sensory state is completely close to the coloring effect of red yeast pigment, and it has strong light resistance and heat resistance, which is beneficial to solve the problem of fading in the processing of meat filling products in China.

4

Nitroso-hemoglobin pigment

The nitroso hemoglobin pigment is produced by directly combining hemoglobin in the blood of a livestock or a hemoglobin in pig blood with a nitroso group. Nitroso-hemoglobin is sensitive to light and Fe 2+ and is easily damaged by peroxide oxidation. It has good thermal stability and high solubility, and has no special requirements for use.

The use of nitrosyl hemoglobin instead of nitrite as a coloring agent has achieved good results in meat products, which not only ensures that the meat products have bright red rose color, but also reduces the amount of NO 2- residues in the meat products. Some researchers used NO-products of hemoglobin and sodium nitrite in pig blood to synthesize nitrosohemoglobin, which was added to sausages as a hair coloring agent. Through test analysis and testing, the product has good color development, stable and long-lasting, unique flavor and certain anti-corrosion effect, while the residual amount of NO 2- in sausage is only 1.75×10 -6 , which can realize the low nitrification of meat products.

5

Lycopene

Lycopene is a non-vitamin A premise carotenoid, a natural pigment synthesized by plants or microorganisms, and is a new type of meat product added with pigment. Lycopene is a deep red fat-soluble pigment, insoluble in water, insoluble in methanol, ethanol, etc., soluble in ether, petroleum ether, etc., and the oil solution is yellow-orange.

Lycopene not only has a variety of health and anti-oxidation functions, but also has a good coloring effect, and has become a new natural product of meat products instead of nitrite research and development by meat processing enterprises. Some researchers have added tomato products (such as tomato sauce) to the meat stuffing, and studied the physical and chemical properties of the meat in storage and the changes in microbial growth. The study found that the lycopene-added meat has improved antioxidant properties and the color is relatively stable during storage. At the same time, the acidity of the tomato product itself will lower the pH of the meat, which will inhibit the growth of some spoilage microorganisms. From this experiment, it can be concluded that lycopene can partially replace nitrite to a certain extent, as an antiseptic preservative for meat foods, and also a good natural preservative.