Anthocyanins are flavonoids in fruits and vegetables that render them vivid red to blue. To date, there have been more than 635 anthocyanins identified in nature, featuring six common aglycones and various types of glycosylations and acylations. Dietary consumption of anthocyanins is high compared to other flavonoids, owing to their wide distribution in plant materials. Based upon many cell-line studies, animal models, and human clinical trials, it has been suggested that anthocyanins possess anti-inflammatory and anti-carcinogenic activity, cardiovascular disease prevention, obesity control, and diabetes alleviation properties, all of which are more or less associated with their potent antioxidant property. Evidence suggests that absorption of anthocyanins occurs in the stomach and small intestine. Epithelial tissue uptake seems to be highly efficient, yet transportation into circulation, tissue distribution, and urine excretion are very limited. The bioactivity of bioavailable anthocyanins should be a focus of future research regarding their putative health-promoting effects.

The color of food is often associated with the flavor, safety, and nutritional value of the product. Synthetic food colorants have been used because of their high stability and low cost. However, consumer perception and demand have driven the replacement of synthetic colorants with naturally derived alternatives. Natural pigment applications can be limited by lower stability, weaker tinctorial strength, interactions with food ingredients, and inability to match desired hues. Therefore, no single naturally derived colorant can serve as a universal alternative for a specified synthetic colorant in all applications. This review summarizes major environmental and biological sources for natural colorants as well as nature-identical counterparts. Chemical characteristics of prevalent pigments, including anthocyanins, carotenoids, betalains, and chlorophylls, are described. The possible applications and hues (warm, cool, and achromatic) of currently used natural pigments, such as anthocyanins as red and blue colorants, and possible future alternatives, such as purple violacein and red pyranoanthocyanins, are also discussed.

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