Copigmentation and stabilization of anthocyanins using organic molecules and encapsulation techniques

Natural colorants/pigments such as anthocyanins, carotenoids, betalains, and chlorophylls have been generally used in the food industry as coloring agents. However, there are challenges related to color fading during food processing, storage, and commercialization due to the low stability of natural colorants compared to synthetic ones. Among them, anthocyanins are potential food colorants due to their color, low toxicity, and biological properties. However, the low chemical and thermal stability of anthocyanins have limited their use on a commercial scale. Copigmentation is the most commonly used technique for anthocyanin stabilization. This technique provides many advantages associated with the stability of anthocyanins. Natural anthocyanin pigments and copigments (e.g. polymers, phenolic compounds, and carbohydrates) form non-covalent complexes, which stabilize and modulate colors in a wide range of plants, fruits, and food products derived from them (including wines, jams, purees, and syrups). Over the past decade, research studies have been conducted to understand the molecular structure of copigment and the mechanism of copigmentation. This review summarizes this phenomenon to provide a comprehensive description of the interactions between anthocyanin and copigment (the dispersion and electrostatic components of 7C -7C stacking, the hydrophobic effect, and hydrogen-bonding) occurring in copigmentation complexes. The trend of integrating copigmentation and encapsulation has been recently started to develop. In this paper, we also attempt to provide a comprehensive view of the effective approaches including spray and freeze-drying, emulsification, gelation, and their combinations for encapsulating copigmented anthocyanins.