Stability of betalain pigments of red beet

Abstract

Although pigments of biological origin are intensely researched for their market potentials and health bene fi ts, their stability, from the maturity status of the source material to their processing and products into which the pigments are incorporated and the storage of those products, is shrouded with many problems. Both extrinsic and intrinsic factors affect the prospective arrays of applications of natural pigments such as betalains. Although the maturity of the red beet may not be the major quality trait in sourcing, the various processing steps, starting from the selection of the extraction medium, extraction conditions, product concentration, storage, transportation and incorporation into products, are huge tasks. The extrinsic factors affecting betalain stability include oxygen, temperature, pH, light and chemicals of processing and food products. On the other hand, the intrinsic factors in the red beet, apart from the quality of the source material, are mainly enzymes: b -glucosidases, polyphenoloxidases (PPOs) and peroxidases (PODs). The current chapter is a compilation of research progress made in understanding the factors affecting the stability of betalains, the chemical changes taking place during degradation and their further fate. Improvements in processing/extraction techniques and storage conditions that impart stability to betalain pigments are discussed. Additionally, application of fermentation and other advanced processes used for the preparation of pigments and food formulations are discussed.