Beet red pigment

Colors used in food are divided into two categories: synthetic colors and natural colors. In recent years, due to the controversy over the safety of synthetic colors, people are more interested in natural colors that are safe, non-toxic and have nutritional and health care effects, and natural colors have become the main direction for the development of the coloring industry.

Beet red pigment is widely found in Quinoa, Amaranthaceae, Cactaceae, Shangluke and other plants, of which Quinoa is most familiar with the red beet, beet red pigment is quinoa plant red beet extracted from water-soluble natural food coloring, belongs to pyrimidine derivatives, the basic chromophore 1,7-diazepane alkaloids, is the red beet in the colored compounds in the general name, by the red beet anthocyanin and yellow beet It consists of red beetroot anthocyanin and yellow beetroot yellow pigment.

Physical and chemical properties

2.1 Solubility

Beet red pigment is soluble in water and aqueous solvents, water-soluble pigment, insoluble in acetic acid, propylene glycol, insoluble in anhydrous ethanol, glycerol, acetone, chloroform, oil, ether and other organic solvents.

2.2 Acid-base environmental reaction properties

Beet red pigment is purple-red liquid, powder or granular solid, but its tone is affected by PH value, when the PH value of 3.0-7.0 is red, and more stable; PH in 4.0-5.0 is the most stable; when PH <4.0 or PH> 7.0, the color of the red to purple; when PH> 10.0, beet red pigment in the conversion of beet pigment into beet yellow, the color of solution quickly turn yellow, thus indicating that the beet red pigment is red, red and yellow, and the color of solution quickly turn yellow. When PH＞10.0, beet red pigment in beet chromoside converted to beet yellow, the color of the solution rapidly changed to yellow, which indicated that beet red pigment was more stable under acidic and neutral conditions.

Since the PH value of most foods is between 3.0-7.0, and the color of beet glycosides will not change in this PH range, so the color of foods containing beet red pigment is generally not affected by PH value.

2.3 The effect of light on pigment stability

Lu Bingfu et al. found that natural light on the stability of beet red aqueous solution will have an impact, long time placed in natural light, the color will fade until yellow, while the natural light on the beet red pigment 50% ethanol solution has less impact.

Wu Chengrong et al. formulated beet red pigment into a certain concentration, irradiated under 40w of ultraviolet light for 1h, 3h, 4h, 6h, 10h, respectively, and the residual amount of its absorbance ratio was counted, and it was found that the rate of loss of beet red pigment was very small, which indicated that the ultraviolet light had less effect on the stability of beet red pigment.

2.4 The effect of heat on the stability of pigments

Beet red has the best thermal stability at PH 4.5, while overall beet red is less stable and heat resistance decreases with increasing temperature. In order to reduce the loss of pigment when extracting, and at the same time to achieve the full effect of extraction, generally selected around 25 ℃ to carry out.

2.5 The effect of metal ions on the stability of pigments

Metal ions have a certain effect on the stability of beet sugar, too much iron ions, copper ions, manganese ions, calcium ions, etc. can promote the degradation of beet sugar, reduce the color of beet red, so the application, it is necessary to add appropriate metal chelating agent to remove metal ions.

2.6 The effect of food additives on the stability of pigments

The use of hydrogen peroxide on beet red pigment oxidation resistance experiment, with the increase of hydrogen peroxide and the extension of the action of time, beet red pigment loss rate accelerated, indicating that the beet red pigment is easy to be oxidized, without using the concentration of sodium nitrite on beet red pigment reduction resistance experiment, the experiment shows that a high concentration of reductant on beet red pigment has a greater impact, concluded that beet red pigment reduction resistance is worse, so in the production and application should avoid the use of sodium nitrite with the red pigment, so in the production and application should be avoided. Therefore, contact with oxidizing and reducing agents should be avoided in production and application.

In addition, glucose, citric acid, sodium benzoate and other additives have less influence on the stability and color of beet red pigment, and can be used in food at the same time. Vitamin C has a degrading effect on beet red pigment, so it should be used differently when using different additives.

Application of beet red in food

Beet red pigment has bright color, uniform coloring, no peculiar smell, and has better coloring function. Beet red pigment is widely used in the coloring of beverages, ice cream, some liquors, candies, pastries, meat products and many other foods.

The coloring of cooked ham with powdered beet red pigment (compared with erythrosine coloring) was still stable after 60d of storage under refrigerated condition, but the red pigment was degraded after 90d, and the yellow pigment was increased, and the red color was lighter than that of erythrosine coloring.

In the study of removing nitrite in sausage with beet red pigment and chitosan, it was found that chitosan had good water retention ability, but the ability to remove fumonisin nitrate was relatively hot. And beet red pigment has a good ability to remove nitrite, so in the production of sausage process, reduce the amount of chitosan in general, with beet red pigment to be supplemented, can be used as a coloring agent of sausage, but also can be used as a nitrite remover.

In addition, with the improvement of people’s living standards, health products with special functions have a broad market, with antioxidant and anti-cancer effects of beet red pigment can be applied to the development and production of such products.