Applications and Development Trends of Natural Food Colorants

Currently, food colorants are broadly classified into two categories: one is synthetic artificial chemical food colorants, most of which belong to the azo compound family and may pose certain toxicological risks to human health; the other comprises edible colorants derived from natural sources—such as the roots, stems, leaves, flowers, and fruits of plants, as well as animals and microorganisms—which are referred to as natural food colorants.

Applications and Development Trends of Natural Food Colorants
From the perspective of usage levels, food colorants account for only a very small fraction of food products—typically a few parts per thousand, ten thousand, or even one hundred thousand. Nevertheless, their role in other applications and their breadth of use in food are unmatched by any other class of food additives. In 1979, Professor Eskin N.A.W. of the United States, after evaluating how color, aroma, and texture influence product quality, noted that although food colorants are used in minute quantities, color alone contributes roughly 45% to the overall quality assessment of a food product. This finding theoretically reinforces the centuries‑old, most direct and traditional criterion for judging food: the quality of a product is first judged by its color, aroma, and taste, with color taking precedence. In practice, it is precisely the availability of red, orange, yellow, green, purple, and other colored food colorants that has given rise to the vibrant, multicolored foods now found on supermarket shelves, enriching both the culinary landscape and the broader tapestry of social life. It can be confidently predicted that, as human society advances, living standards improve, and people’s aspirations for health grow stronger, the variety and scope of applications for natural food colorants will continue to expand, while their quality and functional benefits to human health will steadily increase. Consequently, natural food colorant products are poised for enduring popularity, with bright prospects ahead.

1. Historical Evolution of Natural Pigments

It can be said that the utilization of color is one of the hallmarks of human progress. As humanity emerged from primitive society and developed a desire for aesthetic appeal, the practice of employing pigments began. For instance, during the Ming Dynasty, it was already commonplace—both in the imperial court and among fashionable women in civilian circles—for people to dye their fingernails with the root bark of plants belonging to the genus Lithospermum as a form of adornment. Similarly, dyeing hand‑woven white cloth using the husks of red sorghum to make bridal garments, bedding, and other textiles was a widely adopted technique. Moreover, red rice or the leaves and juices of certain colored plants were often incorporated into dishes and meals. With societal advancement, the use of natural pigments gradually spread throughout the food and cosmetics industries, accompanied by steadily improving processing techniques, until natural colorants became an indispensable element of enhancing everyday life. This trend persisted until the mid‑19th century, when artificially synthesized dyes made their appearance.

In 1856, after Professor W.H. Perkins of the United Kingdom invented the first synthetic organic dye, “aniline purple,” rapid advances in industrial production led to the successive synthesis of numerous organic dyes. Thanks to their vivid hues, strong tinting power, excellent stability, consistent quality, easy solubility and compatibility for color blending, as well as the cost‑reducing advantages of large‑scale industrial manufacturing, these synthetic dyes quickly supplanted natural pigments and found widespread use in industries such as food processing. The number of available varieties soon exceeded one hundred, and production continued to grow steadily. According to relevant data, during that period, some countries in Europe, Asia, and North America recorded annual growth rates of over 2% in synthetic organic dye production, while certain nations in South America, Asia, and Africa posted even higher rates—exceeding 7%. Taking the United States, where the food industry was particularly advanced, as an example, its output reached more than 2,000 tons by 1982. This trend of expansion persisted for roughly a century. In essence, the more than one hundred years following Professor Perkins’s invention of the first synthetic organic dye in 1856 marked both a period of explosive growth for synthetic pigments and a phase of rapid expansion for the food industry. During this time, industrially produced synthetic dyes largely replaced natural colorants.

Since the advent of the 20th century, with the continuous advancement of toxicology and analytical chemistry, humanity has gradually elucidated the metabolic pathways of synthetic colorants in the human body. It has become clear that many synthetic colorants pose significant risks of chronic toxicity, teratogenicity, and carcinogenicity, prompting a renewed focus on their toxicological and genotoxicological evaluation. Countries around the world have invested substantial human and financial resources and enacted relevant regulations to impose strict controls on synthetic colorants whose safety profiles remain incompletely characterized.

A striking example: Following the successive enactment of a series of regulations, the United States added an amendment in 1958 stipulating that any food additive, regardless of the dose at which it is used, would be banned if it was found to cause cancer in experimental animals. In 1969, the U.S. President at the time ordered a 50-year literature review of all food additives in use and commissioned the National Academy of Sciences to conduct a statistical survey aimed at determining the daily intake of each additive by every individual. To date, this effort remains ongoing, having already cost over 90 million U.S. dollars, while also mandating the suspension of certain additives pending the completion of toxicological testing.

On the basis of strict restrictions on the types and levels of use, Japan initiated chronic toxicity studies in 1974 for more than 30 food additives, banning without exception any substances that tested positive in carcinogenicity assays. To further enhance the safety of food additives, Japan’s National Institute of Health spent US$12.5 million to establish, in 1978, a state-of-the-art safety bioassay research center equipped with world‑class facilities. The facility covers 7,221 square meters; its animal housing is maintained under strictly sterile conditions, with temperature, humidity, and ventilation all controlled by computerized systems. Toxicity testing is conducted simultaneously on rats and mice, beginning with subchronic studies and proceeding to chronic studies using doses set at one‑half to one‑quarter of the no‑observed‑adverse‑effect level.

In 1958, the Shanghai Institute of Biochemistry of the Chinese Academy of Sciences conducted toxicological tests on the synthetic food colorant “Cream Yellow” and found that it was carcinogenic in mice. In 1959, under the leadership of the State Science and Technology Commission, a nationwide survey was carried out to assess the production, stockpiles, sales, and usage of synthetic food colorants in various cities; any synthetic colorants suspected of toxicity or with unclear chemical structures were promptly ordered to be destroyed or repurposed. In 1960 and again in 1989, China conducted two rigorous reviews of the synthetic food colorants then in use, re-evaluating both their varieties and permitted usage levels.

In Europe, countries such as Denmark, Norway, the United Kingdom, and France, as well as several nations in Africa and Asia, have successively enacted a series of regulations restricting or banning the use of synthetic food colorants.

The FAO/WHO Joint Expert Committee on Food Additives has convened several sessions to conduct a case-by-case re-evaluation and reassessment of food additives, with particular emphasis on synthetic colorants.

Due to in-depth research on the safety of synthetic food colorants, it has been found that many synthetic dyes are toxic to humans, and some can even form carcinogenic substances within the body. Consequently, countries around the world, along with the World Health Organization, have enacted a series of regulations and guidelines, leading to the removal of numerous harmful synthetic varieties from the lists of permitted additives in various nations. Today, the number of approved synthetic food colorants is quite limited: at their peak, more than 100 synthetic dyes were in use worldwide, whereas now the United States permits only seven, China eight, the United Kingdom twenty-two, Japan twelve, and the Czech Republic ten. Countries such as Sweden, Finland, Norway, India, Denmark, and France have long since banned azo‑based colorants, and some—like Norway—have completely prohibited the use of all chemically synthesized colorants.

Under these circumstances, particularly after the United States banned the use of the synthetic colorant amaranth in 1976, countries around the world began to place great emphasis on the development and application of natural colorants and non‑toxic, harmless food additives, quickly sparking a surge in research and innovation in this field.

As human science and technology continue to advance, artificial synthetic colorants that have been used for over a century are being or will soon be gradually replaced by edible natural colorants derived from plants, animals, and microorganisms.

2 Applications and Development Trends of Natural Food Colorants

Driven by consumers’ growing preference for natural products and their emphasis on health and safety, as well as the demands of a globalized economy following China’s accession to the WTO, the development of edible natural colorants has accelerated. According to statistical data, between 1971 and 1981, 126 patents related to food colorants were publicly disclosed worldwide, with 87.5% pertaining to edible natural colorants.

2.1 A Sharp Increase in Usage

In 1995, Japan’s consumption of natural food colorants reached 23,604 tons, while synthetic food colorants totaled only 186 tons. At present, Japan has 45 factories producing natural food colorants. In the United States, in 1976, the use of natural food colorants exceeded 4,500 tons—five times the amount of chemically synthesized colorants. By contrast, in China in 1996, the output of synthetic colorants was approximately 800 tons, whereas the production of natural food colorants amounted to about 10,000 tons. Today, China boasts more than a hundred factories engaged in the production of natural food colorants.

2.2 Variety of Varieties

At present, more than 100 edible natural colorants have been developed worldwide. China has officially approved 47 of them (as of 1998), Japan lists approximately 102 as permitted for use, the European Community permits 13, and the United Kingdom allows 26.

2.3 Sharp Increase in Output Value

The global market for food colorants is valued at approximately US$1.34 billion, with synthetic colorants accounting for about US$400 million and natural colorants around US$940 million. In recent years, the growth in synthetic colorants has been modest, whereas natural food colorants have been expanding at an annual rate of roughly 4%.

2.4 Abundant raw materials

The raw materials used to extract edible natural pigments are predominantly plant-based and include: (1) edible natural pigments derived from cultivated plants, such as capsanthin, anthocyanins from radishes, betanin from beets, curcumin from turmeric, carthamin from safflower, and red rice and black rice pigments; (2) edible natural pigments obtained from agricultural by-products or waste, including sorghum red pigment, β‑carotene, purple corn pigment, corn yellow pigment, grape skin pigment, orange peel pigment, peanut seed coat pigment, madder red pigment, vegetable carbon black pigment, and smoked flavoring pigment; and (3) natural pigments extracted from wild plants and wild berries, such as bilberry red pigment, blackcurrant pigment, blueberry fruit pigment, elderberry pigment, mulberry pigment, sea buckthorn yellow pigment, madder pigment, black cherry pigment, maple leaf black pigment, and marigold pigment. These resources are abundant in China, with virtually inexhaustible supply; if harnessed in a scientifically sound and rational manner, they can significantly reduce the cost of producing edible natural pigments, boost economic returns, and, at the same time, hold substantial potential for reshaping the national agricultural production structure.

2.5 Beneficial to Health

Most natural pigments belong to the anthocyanin, flavonoid, and carotenoid classes. Consequently, consuming natural pigments is not only safe and harmless but also often provides essential nutrients, or even serves as a source of vitamins or compounds with vitamin-like properties. Moreover, certain natural pigments exhibit pharmacological activities, offering preventive and therapeutic benefits for specific conditions. Thus, natural pigments not only impart color but also enhance bodily functions, promote health, and help prevent disease.

2.6 Research Trends

Natural food colorants are derived from a wide array of raw materials, offering an astonishing spectrum of hues. The most pressing challenge for researchers is to identify varieties that are abundant, cost‑effective, chemically stable, vividly colored, non‑toxic and safe, and in high demand on the market. This includes developing new extraction methods to harness novel resources, as well as conducting in-depth studies on the stability of existing natural pigments to light, heat, pH, and metal ions, and refining extraction processes and techniques.

Over a decade ago, only the Coca‑Cola Company in the United States held the international patent for a commercially viable water‑soluble form of natural β‑carotene, with a price tag of several tens of thousands of yuan per kilogram. In recent years, China has developed a fermentation‑based process to produce β‑carotene at 90% purity, selling it for 11,000 yuan per kilogram. More recently, Changzhou Fusi Biotechnology Co., Ltd. has successfully extracted a jujube‑red pigment from jujube peel, marking a major breakthrough in the research and development of edible natural colorants.

Although the use of natural food colorants has undergone a tortuous evolution over several decades, and despite their still‑existing limitations, in response to growing consumer demand for health and a return to nature, the development and application of natural food colorants are bound to yield even more remarkable results.