Since 1856 British W.H.Perkins synthesized the first artificial dye aniline violet, artificial dyes have rapidly replaced natural pigments with their unique advantages such as bright color, strong stability, easy compounding and low price. With the introduction of chemical synthetic pigment and its production technology in China, the food industry has begun to use synthetic pigment instead of natural pigment to produce corresponding products. At the beginning of the 20th century, with the deepening of toxicology and biology research, it was found that most of the synthetic edible pigments allowed to be used in the past were harmful to human body in varying degrees, especially with carcinogenic, teratogenic and mutagenic consequences, which attracted great attention, and most of the synthetic pigments with certain toxicity were eliminated.
According to relevant data, China has greatly improved the development, production technology, technology and equipment level of edible natural pigment resources, and made great progress in the variety, output and quality of natural edible pigments. Chinese researchers are still actively researching and developing tea pigment, canna flower pigment, eggplant skin pigment, red glycoside blue pigment, lycopene, medlar red pigment, chestnut shell brown pigment, morning glory pigment, peanut skin pigment, hawthorn red pigment, heme, cockscomb red pigment, gray hair raspberry red pigment and so on.
The functionality of natural edible pigments is increasingly recognized by people. For example, carotenoids can be converted into vitamin A in human body, which has many physiological functions such as keeping epithelial cells healthy, maintaining normal vision and improving immunity. Monascus rice flour, as a natural colorant, contains lovastatin which lowers blood pressure. Flavonoid natural pigment has the function of softening blood vessels and enhancing blood vessel elasticity, and red yeast blood lipid-lowering products have entered the domestic and foreign markets. The microencapsulation of capsanthin, chlorophyll and natural β -carotene refined by supercritical extraction is deepening. For example, the varieties being developed are: Schisandra red pigment, perilla pigment, pyracantha pigment, radish pigment, hawthorn pigment, sunflower red pigment, blackcurrant pigment, tea pigment, persimmon peel pigment, nightshade pigment and so on. And many of them have shown a good momentum. For example, the blue melanin content of Vaccinium bracteatum leaves in Zhejiang is as high as 18.7%, which is easily soluble in water and has good light and heat resistance. Anthocyanin in Xishuangbanna, Yunnan Province is a water-soluble red pigment with strong dyeability. The content of brown pigment in Castanopsis eyrei shell is very high, and the brown color has no obvious change between pH 8 ~ 1 1, and the coloring is strong and stable. The cactus fruit in Hainan Island contains a lot of purplish red pigment, which belongs to beet compounds and has great development and utilization value. The content of red pigment in berries is the highest (the content of anthocyanin in fresh fruits is 0.525%). The content of betanin in Phytolacca acinosa Berry is 75% higher than that in sugar beet, and the root tuber of this plant is traditional Chinese medicine.
There are still two major problems in the research and development of natural edible pigments: one is the lack of pigment resources with commercial use value; The second is the stability of natural edible pigment itself. This leads to the high price of natural edible pigment, which also limits its popularization in application to a great extent.
The biggest feature of natural edible pigment is its high safety and huge market, and there are more and more domestic research and development units. There are dozens of reports and patents about new resources, new varieties and new production technologies of natural edible pigments every year. Especially in the search for new pigment resources, some achievements have been made and some good signs have been found, such as extracting natural pigments from marine life.
In order to solve the problem of poor stability of natural edible pigment, people have also made various explorations and made some progress, such as combining beet red with tea pigment, which greatly improved its stability; Carotenoids are oil-soluble pigments with strong heat resistance and poor light resistance. When they are combined with VC, VE or natural antioxidants, their light resistance can be greatly enhanced. Alum, sodium tartrate, phosphoric acid and so on. When used with anthraquinone natural pigment, it is used as a stabilizer to prevent discoloration. Chlorophyll becomes a very stable green pigment by replacing magnesium with copper and then making it into sodium salt or potassium salt. Microencapsulation technology is used to improve the stability of natural pigment, and biotechnology can also be used to change the color tone of natural edible pigment and expand its application scope. For example, the research and development of gardenia pigment series shows that gardenia yellow pigment is bright yellow and water-soluble. Because its components contain odorous aglycone, it reacts with primary amino substances to form pigment intermediates. When pH, temperature and oxygen conditions change, it can obtain cyan, blue and red tones. So as to obtain new pigments such as gardenia blue, gardenia green, gardenia red and the like, and can also be blended into other colors, thereby expanding the application range of natural edible pigments and opening up a broader prospect for the application of natural edible pigments.
Development Prospect With the call of "returning to nature" and the gradual discovery of some physiological activities of natural edible pigments, people will pay more and more attention to and love natural edible pigments, especially functional natural pigments, which have become the development trend of natural edible pigments because of their natural sources, safety and some physiological functions.
While developing functional natural pigments, we should also strengthen the practical research of natural pigments. Most of the natural pigments produced are raw materials, which are not suitable to be directly added to food for coloring. The following aspects should be paid attention to in the application of natural edible pigments:
(1) The nature of the food system that needs coloring;
(2) If the food system is a two-phase or multi-phase system (such as water-oil two-phase), it is necessary to find out which phase needs coloring;
(3) Processing methods used in food production;
(4) The food packaging used;
(5) Storage conditions of packaged food;
(6) Nature of natural pigment.
This requires the research and production of compound natural pigments. Through compounding, the new compound products can reach new heights in color, dosage form, stability, pH value and applicability to a certain food application, and finally fully meet the use needs of a certain food, thus making the application of natural pigments more convenient and extensive.