A Sustainable Approach to Natural Food Coloring: Alginate-Based Encapsulation and Stabilization of Beetroot Betalain

Abstract

Betalains are natural, water-soluble pigments that are chiefly extracted from Beta vulgaris(beetroot) and have been widely researched as natural food colorants attributed to their natural coloring ability and antioxidant properties. On the other hand, their use is restricted by their poor stability response against exposure to natural elements like light, temperature fluctuations, oxygen, and changes in pH, which causes rapid decomposition of pigments and loss of coloration. The scope of this research is to improve the stability response of beetroot-extracted betalain against natural element exposure by employing alginate encapsulation and co-encapsulation techniques with food-grade components. Betalain extracts for this research are conducted through a method of methanolic extraction, and the concentration of the pigment is measured by UV-Visible Spectrophotometry at a wavelength of 535 nm. The encapsulation method is performed through the ionotropic gelation method of sodium alginate and calcium chloride, while the co-encapsulation method is performed by embedding L-ascorbic acid, which is naturally recognized as a non-toxic natural antioxidant agent, within the sodium alginate matrix. The above systems were assessed for color retention upon storage, pH stability at an acidic pH of 3 and basic pH of 9, and controlled release properties in an aqueous environment. The results showed that alginate encapsulation of the betalains increased the retention of color stability and pH stability significantly when compared to the free pigment. Alginate co-encapsulation of the betalains performed better in color stability and controlled release properties because of the reduced diffusion caused by the addition of ascorbic acid. Generally, alginate co-encapsulation of the betalains offers a sustainable and food-friendly approach for the stabilization of the betalains for application in food colorants and controlled release systems.