antocyjanin

Antocyjanin, also spelled anthocyanin, is a class of water-soluble plant pigments responsible for red, purple, and blue colors in flowers, fruits, and leaves. Chemically, anthocyanins are glycosides of anthocyanidins; the aglycone part is an anthocyanidin such as cyanidin, delphinidin, pelargonidin, peonidin, petunidin, or malvidin. The sugar moieties attached to the aglycone can include glucose, rhamnose, galactose, or arabinose, producing a wide variety of individual anthocyanins.

Anthocyanins are produced via the flavonoid biosynthetic pathway and are typically stored in the vacuoles of plant cells. They contribute to plant coloration that can attract pollinators and may play roles in defense against herbivores and abiotic stress. The visible color of an anthocyanin-containing tissue is strongly influenced by pH, as well as by metal ions and co-pigmentation interactions, which can shift hues from red to purple to blue.

Stability is a key characteristic: anthocyanins are sensitive to heat, light, pH changes, and oxygen, and their stability is affected by glycosylation and acylation patterns. Acylated anthocyanins and those complexed with metals or co-pigments tend to be more stable. Under alkaline conditions, or with prolonged storage, they can degrade to chalcones and other products.

In food and nutrition contexts, anthocyanins are valued as natural colorants (commonly designated as E163 in the European Union) and are studied for potential antioxidant and health-promoting effects. They occur naturally in many foods and beverages, including berries, grapes, red cabbage, and red onions. See also anthocyanidin and flavonoid.