Chemical Properties of Anthocyanins Sourced from Different Subtropical Fruits

Anthocyanins are one of these important natural pigments present in vascular plants, contributing the orange, red, pink, violet to blue colors in fruits and flowers. Anthocyanins are harmless water-soluble compounds that are easily dissolved in aqueous media. Belonging to the class of flavonoids, anthocyanin synthesis follows the phenylpropanoid pathway. Anthocyanidins along with sugar moiety form the basic structure of anthocyanins. They are neither aromatic nor flavorful, although they have a moderately astringent taste. The rich sources of anthocyanins include grapes, red cabbage, berries, apples, tulips, radishes, olive oil, teas, honey, cocoa, asparagus, banana, pea, fennel, and pear. Several studies have exploited the antioxidant activity of anthocyanins and their preventive action against chronic diseases such as hypertension, liver disorders, inflammation, memory loss, eyesight damage, microbial activities, tumors, and mutations. Instead of only a natural pigment, anthocyanins have the potential to play other roles like antioxidant activity due to their chemical structure. The glycosylation of anthocyanidins (aglycones) forms anthocyanin molecules. Cyanidin, delphinidin, pelargonidin, peonidin, petunidin, and malvidin are the most prevalent anthocyanidins in the human diet. The isolated anthocyanins are very unstable and easily degraded. Several factors influence their stability, including pH, storage temperature, chemical structure, concentration, light, oxygen, solvents, and the presence of enzymes, flavonoids, proteins, and metallic ions.