A Review on Anthocyanin Pigments with respect to its Nutraceutical Properties

Abstract

Anthocyanin pigments are readily degraded during processing and storage of foodstuffs that can have a dramatic impact on color quality and may also affect the nutritional properties. Total anthocyanin pigment content and indices for polymeric color and browning are easily measured with simple spectrophotometric methods. Once individual pigments are identified, their changes can be monitored by high-performance liquid chromatography (HPLC). The edible fruits of 12 plants were extracted in methanol and subjected to solvent–solvent partitioning to yield three fractions, hexane, ethyl acetate, and aqueous. A number of factors affecting anthocyanin stability and color are discussed in this review. Anthocyanins are probably the most spectacular of plant pigments since they are responsible for most of the red, purple and blue pigmentation of flowers, hits and vegetables. However, because of their highly reactive nature, anthocyanins readily degrade, or react with other constituents in the media, to form colorless or brown colored compounds. The presence of an oxonium ion adjacent to carbon 2 makes the anthocyanins particularly susceptible to nucleophilic attack by such compounds as sulfur dioxide, ascorbic acid, hydrogen peroxide and even water. Loss of anthocyanin pigmentation also occurs in the presence of oxygen and various enzymes, and as a result of high temperature processing. Certain degree of pigment stabilization may be conferred by acylation with various organic acids, co pigmentation, self-association and/or metal chelation. In addition, pH has a marked effect on anthocyanin stability, and on the color of media containing these pigments. A number of anthocyanin-rich sources have been investigated for their potential as commercial pigment extracts. Although their application is primarily limited to acidic media, continued research on the chemistry of anthocyanins may lead to application and stabilization of these pigments in a wider variety of food products.