What are the characteristics and applications of food colorants?

Food colorants have the following characteristics
(1) Natural colorants are more natural and soft in tone, which can bring man and nature closer together, but the dyeing ability of natural colorants is poor and the dyeing is not uniform; synthetic colorants are bright in color and are welcomed by consumers, especially children and teenagers.
(2) Natural colorants generally come from plants and animals themselves, no toxic side effects on the human body, compared with synthetic colorants, security is higher, but synthetic colorants have strong coloring power, easy to dissolve, odorless and tasteless, cheap and other advantages and popular.
(3) Most of the natural colorants are sensitive to light and heat, metal, acid and alkali, oxidant, unstable under these conditions, the color tone will change greatly, and synthetic colorants can make up for this shortcoming.
(4) Some natural colorants can be used as natural antioxidants and natural preservatives. Due to the safety problems of synthetic antioxidants and preservatives, more and more consumers tend to use natural antioxidants and preservatives.
(5) Most natural colorants also have both nutritional value and pharmacological effects, and food colorants also have great application prospects in the medical field. For example, red kale pigment has a good effect on human heart disease and atherosclerosis.
Factors affecting the optimization of food colorants
First, the safety factors of food coloring agent with toxicologists and analytical chemists continue to deepen the study, many synthetic coloring agents have been recognized, the disadvantages of synthetic coloring agents gradually exposed. Most of the synthetic colorants are azo compounds, and many of them can be metabolized in the human body to produce α-naphthylamine and β-naphthylamine with toxic side effects. In view of the unsafe factors of synthetic colorants, strict laws and regulations have been formulated both at home and abroad for these synthetic food colorants, and China has also conducted sampling surveys on food colorants being produced and used in various regions.
We know that many substances will show certain toxic side effects if they exceed a certain intake, and likewise, food coloring agents are no exception. As long as the coloring agent is used within the scope permitted by the state, it is generally not harmful to human health. However, at present, there is a wide variety of food coloring agents, and food products with added coloring agents can be found everywhere, so it is possible that the added amount of a certain food coloring agent is qualified, but there will still be toxic side-effects after consumers have repeatedly and abundantly ingested a certain type or a variety of coloring agents.
Second, the stability factor of food coloring agent research on the breakthrough point of natural coloring agent is to improve its quality and stability, chemists in various countries have done a lot of research for this. Usually the stability of natural coloring agent research has the following aspects.
(1) Light factor. Refers to the coloring agent in direct sunlight color changes, for example, chlorophyll is widely present in plant leaves and stems, easy to decompose when exposed to light, in order to improve its stability, generally made of copper sodium salt.
(2) Temperature factor. Considering the heat resistance of coloring agent, saffron yellow pigment has poor heat resistance, if used in food containing high Vc can improve its stability.
(3) Acid-base factor. Refers to the coloring agent in the acidic or alkaline conditions of the color as well as the stability of the changes, such as β-carotene is widely present in carrots and algae, in the weak alkaline conditions are more stable, but easy to decompose in acidic conditions, if you add a small amount of Vc can improve its stability; rosehip coloring agent color with the pH value of the solution changes, acidic conditions is red, neutral is purple, alkaline can improve its stability. The color of rosehip pigment changes with the pH value of the solution, red in acidic condition, purple in neutral condition and blue in alkaline condition.
(4) Metal ions. Commonly has the copper ion, the sodium ion, the magnesium ion, the iron ion and so on, the gardenia pigment to the iron ion’s tolerance is not strong, some metal ions can make the coloring agent to change the color or even the fading color, and some metal ions can make some coloring agent stability enhancement, such as chlorophyll makes the copper sodium salt can improve the stability.
(5) antioxidant and reducing agent factors. Commonly used antioxidants are Vc, sodium thiosulfate, for example, safflower yellow pigment due to heat resistance is not good, sensitive to metal ions, adding a small amount of Vc can greatly improve its stability.
(6) Some compounds such as sucrose, alum, tartrate factor. For example, the yellow pigment in the addition of alum and tartaric acid salt after its stability can be significantly increased.
(7) Some colorants and another colorant combination of its stability can also be improved, such as beet red and beet red two colorants combined with each other after the stability of the obvious increase.
(8) Solubility factors. Grape skin pigment and perilla pigment are water-soluble colorants, while red rice pigment and comfrey pigment are fat-soluble colorants. In addition, the salt resistance and microbial resistance of the colorant also have a certain effect on the colorant itself.