Anthocyanin : Definition, Classification and function

Anthocyanin

What is the meaning of Anthocyanin ?

žAnthocyanin from the Greek words are

   - anthos, a flower;

   - kyanos, dark blue

žAnthocyanins are water soluble pigment that is naturally present in various plant species.

žAnthocyanins are flavonoid pigments that are widely present in plants responsible for providing almost all the colors red, blue and purple displayed in the flower, fruit and other plant tissues.

 Structure

 
Their structure is based on a C15 skeleton consisting of a chromane ring bearing a second aromatic ring B in position 2; the cyclic structures are arranged in the pattern C-6–C-3–C-6 (phenyl-2-benzopyrilium).

Classification

žAnthocyanins show high diversity in nature but all are based on a reduced number of basic anthocyanidin structure.

žAnthocyanins are classified by the number of sugar molecules in their structures (monosides, biosides, triosides). žColor is also affected by the number of hydroxyl and methoxyl groups: if more hydroxyl groups, then the color goes toward a more bluish shade; if more methoxyl groups, then redness is increased.

žSix most common anthocyanidins in nature are cyanidin, pelargonidin, peonidin, delphinidin, petunidin, and malvidin.

Functions

žColor and Ecological Functions

-  As flavonoids, anthocyanins have important roles in nature such as antioxidant, photoprotection, defense mechanisms, as well as other ecological functions (symbiosis phenomena).

 - The relationship between the anthocyanin type (flower color) and the mechanisms of pollination, seed dispersal, and antifeedant is clearly established; as an example, delphinidin colors are common in bee-pollinated families.

 - Some anthocyanins act as biological control agents, such as cyanidin-3-glucoside, which inhibits larval growth in tobacco.

ž Photosynthesis and Photoprotection

- It has been suggested that anthocyanins in leaves increase the amount of available light for photosynthesis and reduce the photoinhibition; this arises because anthocyanins and chlorophyll b absorb in the same region (520 to 530 nm).

- Another important function of anthocyanins is carried out during the development of young leaves; during this period, metabolism is very active and an excess of peroxide is produced. Consequently, the production of free radicals is favored. Under these conditions, anthocyanins act as antioxidant agents by reacting with free radicals.

žCold Injury and Anthocyanins

-Anthocyanins accumulated in vacuoles may protect the vacuole membrane from low temperature injury; however, the role played by anthocyanins in membrane protection remains to be elucidated in the future.

žMarker for Good Manufacturing Practices in Food Processing

-  products are colored by anthocyanins, such as wines, juices, jams, and soft drinks. Before consumers pay for the product, has been undertaken to detect adulteration in these products.

 Thank you....^^